Car radio signal processor

Car radio signal processor
TDA7402
Car radio signal processor
Features
●
3 Stereo inputs
●
3 Mono inputs
●
Dynamic-compression-stage for cd
●
Softstep-volume
●
Bass, treble and loudness control
●
Voice-band-filter
●
Direct mute and softmute
●
Internal beep
●
Four independent speaker-outputs
●
Stereo subwoofer output
●
Independent second source-selector
●
Full mixing capability
●
Pause detector
LQFP44
Digital control:
Description
Stereo decoder:
●
RDS mute
●
No external adjustments
●
AM/FM noiseblanker with several trigger
controls
●
Programmable multipath detector
●
Quality detector output
Table 1.
March 2007
I2C bus interface
The device includes a high performance
audioprocessor and a stereo decoder-noise
blanker combination, with the whole low
frequency signal processing necessary for state
of the art, as well as future car radios. The digital
control allows a programming in a wide range of
all the filter characteristics. The stereo decoder
part also offers several possibilities of
programming, especially for the adaptation to
different IF devices.
Device summary
Part numbers
Package
Packing
TDA7402
LQFP44 (10x 10x 1.4mm)
Tube
Rev 5
1/71
www.st.com
1
Contents
TDA7402
Contents
1
Pin connections and block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2
Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3
Audioprocessor part features: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4
Audioprocessor part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1
4.2
4.3
4.1.1
Full-differential stereo Input 1 (FD1) . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.2
Full-differential stereo Input 2 (FD2) . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.3
Mono differential Input 1 (MD1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.1.4
Mono differential Input 2 (MD2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.1.5
Single ended stereo Input (SE1), single ended mono input (AM) and FMMPX input 18
AutoZero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.2.1
AutoZero for stereo decoder selection . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.2.2
AutoZero remain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Pause detector / MUX-output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3.1
Loudness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3.2
Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3.3
Peak frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.3.4
Loudness order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.3.5
Flat mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.4
SoftMute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.5
SoftStep volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.6
Bass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.7
4.8
2/71
Input stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.6.1
Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.6.2
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.6.3
Quality factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.6.4
DC mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Treble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.7.1
Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.7.2
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Subwoofer application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
TDA7402
5
Contents
4.9
Voice band application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.10
Compander . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.10.1
Anti-clipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.10.2
Characteristic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.10.3
I²C bus timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.11
AC coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.12
Output selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.13
Subwoofer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.14
Speaker attenuator and mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.15
Audioprocessor testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Stereo decoder part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.1
Features: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.2
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.3
Notes about the characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.4
5.3.1
Intermodulation suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.3.2
Traffic radio (V.F.) suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.3.3
SCA (subsidiary communications authorization) . . . . . . . . . . . . . . . . . . 35
5.3.4
ACI (adjacent channel interference) . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Noise blanker part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.4.1
5.5
Multipath detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.5.1
6
Features: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Features: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Functional description of stereo decoder . . . . . . . . . . . . . . . . . . . . . . . 40
6.1
Stereo decoder mute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
6.2
InGain + infilter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.3
Demodulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.4
De-emphasis and highcut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.5
PLL and pilot tone detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.6
Field strength control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.7
EVEL input and gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.8
Stereo blend control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
6.9
Highcut control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3/71
Contents
7
8
9
TDA7402
Functional description of the noise blanker . . . . . . . . . . . . . . . . . . . . . 45
7.1
Trigger path FM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
7.2
Noise controlled threshold adjustment (NCT) . . . . . . . . . . . . . . . . . . . . . 45
7.3
Additional threshold control mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.3.1
Automatic threshold control by the stereo blend voltage . . . . . . . . . . . . 46
7.3.2
Over deviation detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.3.3
Multipath level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.3.4
AM mode of the noiseblanker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Functional description of the multipath detector . . . . . . . . . . . . . . . . . 47
8.1
Quality detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
8.2
Testmode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.3
Dual MPX usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.3.1
Feature description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.3.2
Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
I2C bus interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.1
Interface protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.2
Auto increment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.3
Transmitted data (send mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.4
Subaddress (receive mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
9.5
Data byte specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
10
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
11
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
12
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4/71
TDA7402
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 11.
Table 12.
Table 13.
Table 14.
Table 15.
Table 16.
Table 17.
Table 18.
Table 19.
Table 20.
Table 21.
Table 22.
Table 23.
Table 24.
Table 25.
Table 26.
Table 27.
Table 28.
Table 29.
Table 30.
Table 31.
Table 32.
Table 33.
Table 34.
Table 35.
Table 36.
Table 37.
Table 38.
Table 39.
Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Attack times vs soft-step times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Electrical characteristics of multipath detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Transmitted data (send mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Reset condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Subaddress (receive mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Main selector (0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Main loudness (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Volume (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Treble filter (3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Bass filter (4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Mixing programming (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Soft mute (6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Voiceband (7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Second source selector (8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Second loudness (9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Subwoofer Configuration / Bass (10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Compander (11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Configuration audioprocessor I (12) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Configuration audioprocessor II (13) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Speaker, subwoofer and mixer level-control (14-20) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Testing Audioprocessor (21). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Stereo decoder (22) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Noise blanker I (23) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Noiseblanker II (24) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
AM / FM noiseblanker (25) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
High cut (26) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Fieldstrength control (27) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Multipath detector (28) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Stereo decoder adjustment (29) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Stereo decoder configuration (30) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Testing stereo decoder (31) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5/71
List of figures
TDA7402
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.
Figure 31.
Figure 32.
Figure 33.
Figure 34.
Figure 35.
Figure 36.
Figure 37.
Figure 38.
Figure 39.
6/71
PIN connection (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Input-stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Loudness attenuation @ fP = 400Hz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Loudness center frequencies @ Attn. = 15dB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1st and 2nd order loudness @ Attn. = 15dB, fP=400Hz . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Softmute timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
SoftStep timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Bass control @ fC = 80Hz, Q = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Bass center frequencies @ gain = 14dB, Q = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Bass Quality factors @ Gain = 14dB, fC = 80Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Bass normal and DC Mode @ Gain = 14dB, fC = 80Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Treble Control @ fC = 17.5kHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Treble center frequencies @ gain = 14dB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Subwoofer application with LPF 80/120/160Hz and HPF 90/135/180Hz . . . . . . . . . . . . . . 25
Voiceband application with HPF 300/450/600/750Hz and LPF 3k/6kHz . . . . . . . . . . . . . . 25
Compander block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Compander characteristic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Output selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Application 1 using internal highpass and mono low pass filter . . . . . . . . . . . . . . . . . . . . . 29
Application 2 using internal highpass and external stereo low pass filter . . . . . . . . . . . . . . 30
Application 3 using pure external filtering (e.g. DSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Output selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Vn timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Trigger threshold vs. VPEAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Deviation controlled trigger adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Field strength controlled trigger adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Block diagram of stereo decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Signals during stereo decoder's SoftMute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Signal control via SoftMute pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Internal stereo blend characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Relation between internal and external LEVEL voltages for setup of stereo blend . . . . . . 43
Highcut characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Block diagram of the noise blanker. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Block diagram of the multipath detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Dual MPX input diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Application diagram (standard configuration) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Application diagram (Dual MPX mode). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
LQFP44 (10x10) Mechanical data and package dimensions . . . . . . . . . . . . . . . . . . . . . . . 69
TDA7402
Pin connections and block diagram
MD2G
MD2
MD1G/SE4L
MD1/SE4R
MUX/PAUSE
CREF
ACOUTL
ACOUTR
SWINL
SWINR
ACINLF
PIN connection (top view)
44
43
42
41
40
39
38
37
36
35
34
30
OUTLF
FD1R+/SE3R
5
29
OUTLR
FD1R-/SE2R
6
28
OUTRF
FD2L+
7
27
OUTRR
FD2L-
8
26
OUTSWL
FD2R+
9
25
OUTSWR
FD2R-
10
24
OUTSSL
AM
11
23
OUTSSR
12
13
14
15
16
17
18
19
20
21
22
VDD
4
SCL
ACINRR
FD1L-/SE2L
SDA
31
GND
3
SM
ACINRF
FD1L+/SE3L
QUAL
32
MPOUT
ACINLR
2
MPIN
33
SE1R
LEVEL
SE1L
1
MPX
Figure 1.
AM IF
1
Pin connections and block diagram
D00AU1131
7/71
8/71
AM-IF
MPX
SEN
MD2G
MD2
MD1G
MD1
SER
SEL
FD2R-
FD2R+
FD2L-
FD2L+
FD1R-
FD1R+
AM
PHONE
NAVI
MAIN
PLL
BEEP
SECOND
SOURCE
SELECTOR
MIXING
SELECTOR
MAIN
SOURCE
SELECTOR
80KHz
LP
INPUTMULTIPLEXER
AUX
CHG
IN GAIN
+
PILOT
CANCELLATION
PAUSE
PIL.
DET.
MUTE
IN-GAIN
+ AUTO
ZERO
MPIN
MPOUT
MULTIPATH
DETECTOR
25KHz
LP
SOFT
STEP
VOLUME
COMPANDER
SOFT
MUTE
DEMODULATOR
+ STEREO ADJUST
+ STEREO BLEND
LOUDNESS
ANTI CLIP.
INPUT
LOUDNESS
SM
AM/FM
NOISE
BANKER
TREBLE
PULSE
FORMER
S&H
DIGITAL CONTROL
BASS
A
LEVEL
D
HIGH
CUT
HP
LP
VOICE BANDPASS
ACINRR
SWINL
ACINRF
SWINR
QUAL.
SUBWOOFER
+ PHONE
CONTROL
SW
REAR
OUTPUT
SELECTOR
FRONT
ACIN
ACINLF
SUPPLY
D00AU1130
IIC BUS
MONO-FADER
CREF
GND
VDD
QUAL
SCL
SDA
OUTSSR
OUTSSL
OUTSWR
OUTSWL
OUTRR
MONO-FADER
OUTRF
OUTLR
MONO-FADER
MIXER
OUTLF
MONO-FADER
MONO-FADER
MONO-FADER
Figure 2.
FD1L-
FD1L+
MUX
Pin connections and block diagram
TDA7402
Block diagram
ACINLR
ACOUTR
ACOUTL
TDA7402
2
Electrical specifications
Electrical specifications
VS = 9V; Tamb = 25°C; RL = 10kΩ; all gains = 0dB; f = 1kHz; unless otherwise specified
Table 2.
Electrical characteristics
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
70
100
130
kΩ
Input selector
Rin
Input resistance
VCL
Clipping level
2.2
2.6
VRMS
SIN
Input separation
80
100
dB
Min. input gain
-1
0
+1
dB
GIN MAX Max. input gain
13
15
17
dB
0.5
1
1.5
dB
Adjacent gain steps
-5
1
5
mV
GMIN to GMAX
-10
6
10
mV
GIN MIN
GSTEP
VDC
Voffset
all single ended Inputs
Step resolution
DC steps
Remaining offset with autozero
0.5
mV
Differential stereo inputs
Rin
GCD
CMRR
eNO
Input resistance
(see Figure 3)
Gain
Common mode rejection ratio
Differential
70
100
130
kΩ
-1
0
1
dB
-5
-6
7
dB
-11
-12
-13
dB
VCM = 1VRMS @ 1kHz
46
70
dB
VCM = 1VRMS @ 10kHz
46
60
dB
only at true differential input
Output-noise @ speaker outputs 20Hz - 20kHz, flat; all stages 0dB
9
15
µV
72
kΩ
Differential mono inputs
Rin
CMRR
Input impedance
Common mode rejection ratio
Differential
40
56
VCM = 1VRMS @ 1kHz
40
70
dB
VCM = 1VRMS @ 10kHz
40
60
dB
Mix-gain = 6dB
250
350
500
mV
fBeep1
570
600
630
Hz
fBeep2
740
780
820
Hz
fBeep1
1.48
1.56
1.64
kHz
fBeep1
2.28
2.4
2.52
kHz
Beep control
VRMS
fBeep
Beep level
Beep frequency
9/71
Electrical specifications
Table 2.
TDA7402
Electrical characteristics (continued)
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
Mixing control
MLEVEL
Mixing ratio
Main / mix source
-6/-6
dB
GMAX
Max. gain
13
15
17
dB
AMAX
Max. attenuation
-83
-79
-75
dB
ASTEP
Attennuation step
0.5
1
1.5
dB
225
300
W
Multiplexer output (1)
ROUT
Output impedance
RL
Output load resistance
CL
Output load capacitance
VDC
2
DC voltage level
kΩ
10
nF
4.3
4.5
4.7
V
Loudness control
ASTEP
Step resolution
0.5
1
1.5
dB
AMAX
Max. attenuation
-21
-19
-17
dB
fP1
180
200
220
Hz
fP2
360
400
440
Hz
fP3
540
600
660
Hz
fP4
720
800
880
Hz
fPeak
Peak frequency
Volume control
GMAX
Max. gain
30
32
34
dB
AMAX
Max. attenuation
-83
-79.5
-75
dB
ASTEP
Step resolution
0
0.5
1
dB
G = -20 to +20dB
-0.75
0
+0.75
dB
G = -80 to -20dB
-4
0
3
dB
2
dB
EA
Attenuation set error
ET
Tracking error
VDC
Adjacent attenuation steps
0.1
3
mV
From 0dB to GMIN
0.5
5
mV
DC steps
Soft mute
AMUTE
TD
VTH low
10/71
Mute attenuation
80
100
dB
T1
0.48
1
ms
T2
0.96
2
ms
Delay time
Low threshold for SM
Pin(2)
T3
70
123
170
ms
T4
200
324
600
ms
1
V
TDA7402
Table 2.
Electrical specifications
Electrical characteristics (continued)
Symbol
Parameter
Test condition
VTH high High threshold for SM Pin
RPU
Internal pull-up resistor
VPU
Internal pull-up voltage
Min.
Typ.
Max.
2.5
32
Unit
V
45
58
3.3
kΩ
V
Bass control
CRANGE Control range
ASTEP
fC
QBASS
DCGAIN
+14
+15
+16
dB
0.5
1
1.5
dB
fC1
54
60
66
Hz
fC2
63
70
77
Hz
fC3
72
80
88
Hz
fC4
81
90
99
Hz
fC5
90
100
110
Hz
fC6
117
130
143
Hz
fC7
135
150
165
Hz
fC8
180
200
220
Hz
Q1
0.9
1
1.1
Q2
1.1
1.25
1.4
Q3
1.3
1.5
1.7
Q4
1.8
2
2.2
DC = off
-1
0
+1
dB
DC = on
4
4.4
6
dB
+14
+15
+16
dB
0.5
1
1.5
dB
fC1
8
10
12
kHz
fC2
10
12.5
15
kHz
fC3
12
15
18
kHz
fC4
14
17.5
21
kHz
Step resolution
Center frequency
Quality factor
Bass-DC-gain
Treble control
CRANGE Control range
ASTEP
fC
Step resolution
Center frequency
Pause detector(3)
VTH
Zero crossing threshold
IDELAY
Pull-up current
VTHP
Pause threshold
Window 1
40
mV
Window 2
80
mV
Window 3
160
mV
15
25
3.0
35
μA
V
11/71
Electrical specifications
Table 2.
TDA7402
Electrical characteristics (continued)
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
Input impedance
35
50
65
kΩ
GMAX
Max. gain
14
15
16
dB
AMAX
Max. attenuation
-83
-79
-75
dB
ASTEP
Step resolution
0.5
1
1.5
dB
AMUTE
Output mute attenuation
80
90
Speaker attenuators
Rin
EE
VDC
Attenuation set error
DC steps
Adjacent attenuation steps
0.1
dB
2
dB
5
mV
Audio outputs
VCLIP
Clipping level
RL
Output load resistance
CL
Output load capacitance
d = 0.3%
2.2
2.6
VRMS
2
kΩ
10
nF
30
100
W
4.3
4.5
4.7
V
fHP1
81
90
99
Hz
fHP2
122
135
148
Hz
fHP3
162
180
198
Hz
fHP4
194
215
236
Hz
fHP5
270
300
330
Hz
fHP6
405
450
495
Hz
fHP7
540
600
660
Hz
fHP8
675
750
825
Hz
fLP1
2.7
3
3.3
kHz
fLP2
5.4
6
6.6
kHz
Input impedance
35
50
65
kΩ
GMAX
Max. gain
14
15
16
dB
AATTN
Max. attenuation
-83
-79
-75
dB
ASTEP
Step resolution
0.5
1
1.5
dB
AMUTE
Output mute attenuation
80
90
ROUT
Output impedance
VDC
DC voltage level
Voice bandpass
fHP
fLP
Highpass corner frequency
Lowpass corner frequency
Subwoofer attenuators
Rin
EE
VDC
12/71
Attenuation set error
DC steps
Adjacent attenuation steps
1
dB
2
dB
5
mV
TDA7402
Electrical specifications
Table 2.
Electrical characteristics (continued)
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
fLP1
72
80
88
Hz
fLP2
108
120
132
Hz
fLP3
144
160
176
Hz
Subwoofer lowpass
fLP
Lowpass corner frequency
Differential outputs(4)
RL
load resistance at each output
RDL
load resistance differential
CLMAX
Capacitive load at each output
1VRMS; AC coupled; THD=1%
1
kΩ
2VRMS; AC coupled; THD=1%
2
kΩ
1VRMS; AC coupled; THD=1%
2
kΩ
2VRMS; AC coupled; THD=1%
4
kΩ
CLmax at each output to ground
10
nF
CLmax between output terminals
5
nF
10
mV
30
100
W
4.5
4.7
V
Output muted
6
15
µV
Vi < -46dB
19
dB
Vi < -46dB, Anti-clip = on
29
dB
tAtt1
6
ms
tAtt2
12
ms
tAtt3
24
ms
tAtt4
49
ms
tRel1
390
ms
tRel2
780
ms
tRel3
1.17
s
tRel4
1.56
s
VREF1
Compander reference input-level
VREF2
(equals 0dB)
VREF3
0.5
VRMS
1.0
VRMS
2.0
VRMS
Compression factor
0.5
CDLMAX Capacitive load differential
VOffset
DC offset at pins
ROUT
Output impedance
VDC
DC voltage level
eNO
Output noise
Output muted
-10
4.3
Compander
GMAX
tAtt
tRel
VREF
CF
max. compander gain
Attack time
Release time
Output signal / input signal
General
13/71
Electrical specifications
Table 2.
TDA7402
Electrical characteristics (continued)
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
3
10
15
20
µV
µV
BW = 20Hz - 20kHz
eNO
S/N
d
output muted
all gains = 0dB single ended
inputs
Output noise
Signal to noise ratio
distortion
SC
Channel separation left/right
ET
Total tracking error
all gains = 0dB
flat; VO = 2VRMS
106
dB
bass, treble at +12dB;
a-weighted; VO = 2.6VRMS
100
dB
VIN = 1VRMS ; all stages 0dB
0.005
0.1
%
VOUT = 1VRMS ; bass & treble =
12dB
0.05
0.1
%
80
100
dB
AV = 0 to -20dB
-1
0
1
dB
AV = -20 to -60dB
-2
0
2
dB
1. If configured as multiplexer-output
2. The SM Pin is active low (mute = 0)
3. If configured as pause-output
4. If programmed as subwoofer diff. output
Table 3.
Absolute maximum ratings
Symbol
VS
Parameter
Value
Unit
10.5
V
-40 to 85
°C
-55 to +150
°C
Operating supply voltage
Tamb
Operating temperature range
Tstg
Storage temperature range
VESD
ESD protection (human body mode)
±2000
V
VESD
ESD protection (machine mode)
±200
V
Value
Unit
65
°C/W
Table 4.
Thermal data
Symbol
Rth j-pins
Table 5.
Symbol
Parameter
Thermal resistance junction-pins max
Supply
Parameter
Test condition
VS
Supply voltage
IS
Supply current
VS = 9V
Ripple rejection @ 1kHz
Audioprocessor
(all Filters flat)
SVRR
14/71
Min.
Typ.
Max.
Unit
7.5
9
10
V
35
50
65
mA
60
dB
TDA7402
3
Audioprocessor part features:
Audioprocessor part features:
●
●
Input multiplexer
–
2 fully differential CD stereo inputs with programmable attenuation
–
1 single ended stereo input
–
2 differential mono input
–
1 single ended mono input
–
In-gain 0..15dB, 1dB steps
–
internal offset cancellation (AutoZero)
–
separate second source selector
Beep
–
●
Mixing stage
–
●
●
●
●
●
Beep, phone and navigation mixable to all speaker outputs
Loudness
–
programmable center frequency and frequency response
–
15 x 1dB steps
–
selectable flat-mode (constant attenuation)
Volume
–
0.5dB attenuator
–
100dB range
–
soft-step control with programmable times
Compander
–
dynamic range compression for use with CD
–
2:1 compression rate
–
programmable max. gain
Bass
–
2nd order frequency response
–
center frequency programmable in 8 steps
–
DC gain programmable
–
+ 15 x 1dB steps
Treble
–
●
internal beep with 4 frequencies
2nd order frequency response
–
center frequency programmable in 4 steps
–
+15 x 1dB steps
Voice Bandpass
–
2nd order butterworth highpass filter with programmable cut off frequency
–
2nd order butterworth lowpass filter with programmable cut off frequency
–
selectable flat mode
–
15/71
Audioprocessor part features:
●
●
●
●
Speaker
–
4 independent speaker controls in 1dB steps
–
control range 95dB
–
separate Mute
Subwoofer
–
single ended stereo output
–
independent stereo level controls in 1dB steps
–
control range 95dB
–
separate Mute
Mute Functions
–
direct mute
–
digitally controlled SoftMute with 4 programmable mute-times
Pause Detector
–
16/71
programmable threshold
TDA7402
TDA7402
Audioprocessor part
4
Audioprocessor part
4.1
Input stages
In the basic configuration two full differential, two mono differential, one single ended stereo
and one single ended mono input are available. In addition a dedicated input for the stereo
decoder MPX signal is present.
Figure 3.
Input-stages
MAIN SOURCE
SELECTOR
SE3
FD1/SE2
SE2
15K
FD1-
15K
FD2
1
100K
MD1/SE4
STEREO
FD1+
-
MD2
+
SE1
IN GAIN
100K
AM
1
100K
MUTE
15K
15K
15K
15K
FM
SE3
FD2-
1
100K
-
STEREO
+
FD2+
1
15K
100K
15K
MIXING
SELECTOR
MD2
MD1
SE4
28K
28K
MUTE
FM
MD1G
MIXING STAGE
BEEP
100K
-
MONO
+
MD1
28K
28K
28K
28K
100K
SE4R
SE4R
MD2G
100K
MONO
SE3
+
FD1/SE2
28K
MD1/SE4
FD2
MD2
100K
SE1
STEREO
SECOND SOURCE
SELECTOR
-
28K
MD2
MUTE
IN GAIN
SE1
AM
100K
FM
AM
MONO
100K
MPX
NOISE BLANKER
+
STEREO DECODER
100K
D00AU1142
4.1.1
Full-differential stereo Input 1 (FD1)
The FD1 input is implemented as a buffered full-differential stereo stage with 100kΩ input
impedance at each input. The attenuation is programmable in 3 steps from 0 to -12dB in
order to adapt the incoming signal level. A 6dB attenuation is included in the differential
stage, the additional 6dB are done by a following resistive divider. This input is also
configurable as two single ended stereo inputs (see pin-out).
4.1.2
Full-differential stereo Input 2 (FD2)
The FD2 input has the same general structure as FD1, but with a programmable attenuation
of 0 or 6dB embedded in the differential stage.
17/71
Audioprocessor part
4.1.3
TDA7402
Mono differential Input 1 (MD1)
The MD1 input is designed as a basic differential stage with 56kΩ input impedance. This
input is configurable as a single ended stereo input (see pin-out).
4.1.4
Mono differential Input 2 (MD2)
The MD2 input has the same topology as MD1, but without the possibility to configure it to
single ended.
4.1.5
Single ended stereo Input (SE1), single ended mono input (AM) and
FM-MPX input
All single ended inputs offer an input impedance of 100kΩ. The AM pin can be connected by
software to the input of the stereo-decoder in order to use the AM noiseblanker and AM High
Cut feature.
4.2
AutoZero
The AutoZero allows a reduction of the number of pins as well as external components by
canceling any offset generated by or before the In-Gain-stage (Please notice that externally
generated offsets, e.g. generated through the leakage current of the coupling capacitors,
are not canceled).
The auto zeroing is started every time the DATA-BYTE 0 is selected and needs max. 0.3ms
for the alignment. To avoid audible clicks the Audioprocessor is muted before the loudness
stage during this time. The AutoZero feature is only present in the main signal path.
4.2.1
AutoZero for stereo decoder selection
A special procedure is recommended for selecting the stereo decoder at the main inputselector to guarantee an optimum offset cancellation:
1.
SoftMute or Mute the signal-path
2.
Temporary deselect the stereo decoder at all input selectors
3.
Configure the stereo decoder via IIC-Bus
4.
Wait 1ms
5.
Select the stereo decoder at the main input selector first
The root cause of this procedure is, that after muting the stereo decoder (Step 1), the
internal stereo decoder filters have to settle in order to perform a proper offset cancellation.
4.2.2
AutoZero remain
In some cases, for example if the µP is executing a refresh cycle of the I2C Bus
programming, it is not useful to start a new AutoZero action because no new source is
selected and an undesired mute would appear at the outputs. For such applications the
A619 could be switched in the AutoZero Remain Mode (Bit 6 of the subaddress byte). If
this bit is set to high, the DATABYTE 0 could be loaded without invoking the AutoZero and
the old adjustment value remains.
18/71
TDA7402
4.3
Audioprocessor part
Pause detector / MUX-output
The pin number 40 (Pause/MUX) is configurable for two different functions:
4.3.1
1.
During pause detector OFF this pin is used as a mono output of the main input selector.
This signal is often used to drive a level/equalizer display on the car radio front panel.
2.
During pause detector ON the pin is used to define the time constant of the detector by
an external capacitor. The pause detector is driven by the internal stereo decoder
outputs in order to use pauses in the FM signal for alternate frequency jumps. If the
signal level of both stereo decoder channels is outside the programmed voltage
window, the external capacitor is abruptly discharged. Inside the pause condition the
capacitor is slowly recharged by a constant current of 25µA. The pause information is
also available via I2C Bus (see I2C Bus programming).
Loudness
There are four parameters programmable in the loudness stage:
4.3.2
Attenuation
Figure 4 shows the attenuation as a function of frequency at fP = 400Hz
Figure 4.
Loudness attenuation @ fP = 400Hz.
0.0
-5.0
-10.0
dB
-15.0
-20.0
-25.0
10.0
100.0
Hz
1.0K
10.0K
19/71
Audioprocessor part
4.3.3
TDA7402
Peak frequency
Figure 5 shows the four possible peak-frequencies at 200, 400, 600 and 800Hz
Figure 5.
Loudness center frequencies @ Attn. = 15dB.
0.0
-5.0
dB
-10.0
-15.0
-20.0
10.0
100.0
1.0K
10.0K
Hz
4.3.4
Loudness order
Different shapes of 1st and 2nd-order loudness
Figure 6.
1st and 2nd order loudness @ Attn. = 15dB, fP=400Hz
0.0
-5.0
dB
-10.0
-15.0
-20.0
10.0
4.3.5
100.0
Hz
1.0K
Flat mode
In flat mode the loudness stage works as a 0dB to -19dB attenuator.
20/71
10.0K
TDA7402
4.4
Audioprocessor part
SoftMute
The digitally controlled SoftMute stage allows muting/demuting the signal with a I2C bus
programmable slope. The mute process can either be activated by the SoftMute pin or by
the I2C-bus. This slope is realized in a special S-shaped curve to mute slow in the critical
regions (see Figure 7).
For timing purposes the Bit0 of the I2C bus output register is set to 1 from the start of muting
until the end of de-muting.
Figure 7.
Softmute timing
EXT.
MUTE
1
+SIGNAL
REF
-SIGNAL
1
I2C BUS
OUT
D97AU634
Time
Note:
Please notice that a started mute action is always terminated and could not be interrupted
by a change of the mute -signal.
4.5
SoftStep volume
When the volume level is changed audible clicks could appear at the output. The root cause
of those clicks could either be a DC offset before the volume stage or the sudden change of
the envelope of the audiosignal. With the SoftStep feature both kinds of clicks could be
reduced to a minimum and are no more audible. The blend time from one step to the next is
programmable in four steps.
Figure 8.
SoftStep timing
VOUT
1dB
0.5dB
Time
SS Time
-0.5dB
-1dB
D00AU1170
21/71
Audioprocessor part
TDA7402
Note:
For steps more than 0.5dB the SoftStep mode should be deactivated because it could
generate a hard 1dB step during the blend time.
4.6
Bass
There are four parameters programmable in the bass stage:
4.6.1
Attenuation
Figure 9 shows the attenuation as a function of frequency at a center frequency of 80Hz.
Figure 9.
Bass control @ fC = 80Hz, Q = 1
15.0
10.0
5.0
dB
0.0
-5.0
-10.0
-15.0
10.0
4.6.2
100.0
Hz
1.0K
10.0K
Center frequency
Figure 10 shows the eight possible center frequencies 60, 70, 80, 90, 100, 130, 150 and
200Hz.
Figure 10. Bass center frequencies @ gain = 14dB, Q = 1
15.0
12.5
10.0
7.5
dB
5.0
2.5
0.0
10.0
22/71
100.0
Hz
1.0K
10.0K
TDA7402
4.6.3
Audioprocessor part
Quality factors
Figure 11 shows the four possible quality factors 1, 1.25, 1.5 and 2.
Figure 11. Bass Quality factors @ Gain = 14dB, fC = 80Hz
15.0
12.5
10.0
7.5
5.0
2.5
0.0
10.0
4.6.4
100.0
1.0K
10.0K
DC mode
In this mode the DC-gain is increased by 4.4dB. In addition the programmed center
frequency and quality factor is decreased by 25% which can be used to reach alternative
center frequencies or quality factors.
Figure 12. Bass normal and DC Mode @ Gain = 14dB, fC = 80Hz
15.0
12.5
10.0
7.5
5.0
2.5
0.0
10.0
Note:
100.0
1.0K
10.0K
The center frequency, Q and DC-mode can be set fully independently.
23/71
Audioprocessor part
4.7
TDA7402
Treble
There are two parameters programmable in the treble stage:
4.7.1
Attenuation
Figure 13. shows the attenuation as a function of frequency at a center frequency of
17.5kHz.
Figure 13. Treble Control @ fC = 17.5kHz
15.0
10.0
5.0
0.0
-5.0
-10.0
-15.0
10.0
4.7.2
100.0
1.0K
10.0K
Center frequency
Figure 14. shows the four possible center frequencies 10k, 12.5k, 15k and 17.5kHz.
Figure 14. Treble center frequencies @ gain = 14dB
15.0
12.5
10.0
7.5
5.0
2.5
0.0
10.0
24/71
100.0
1.0K
10.0K
TDA7402
4.8
Audioprocessor part
Subwoofer application
Figure 15. Subwoofer application with LPF 80/120/160Hz and HPF 90/135/180Hz
0.0
-10.0
-20.0
dB
-30.0
-40.0
-50.0
10.0
100.0
Hz
1.0K
10.0K
Both filters, the lowpass and the highpass-filter, have butterworth characteristics so that their
cut off frequencies are not equal, but shifted by the factor 1.125 to get a flat frequency
response.
4.9
Voice band application
Figure 16. Voiceband application with HPF 300/450/600/750Hz and LPF 3k/6kHz
0.0
-10.0
-20.0
dB
-30.0
-40.0
-50.0
10.0
100.0
Hz
1.0K
10.0K
25/71
Audioprocessor part
4.10
TDA7402
Compander
Signal compression
A fully integrated signal compressor with programmable attack and decay times is present in
the A619 (see Figure 17).
The compander consists of a signal level detection, an A/D Converter plus adder and the
normal softstep volume stage. First of all the left and the right InGain-signal is rectified,
respectively, and the logarithm is build from the summed signal. The following low-pass
smooth the output-signal of the logarithm amplifier and improves the low frequency
suppression. The low pass output-voltage then is A/D converted an added to the current
volume-word defined by the I2C bus. Assuming reference level or higher at the compander
input, the output of the ADC is 0. At lower levels the voltage is increasing with 1Bit/dB. It is
obvious that with this configuration and a 0.5dB-step volume stage the compression rate is
fixed to 2:1 (1dB less at the input leads to 0.5dB less at the output).
The internal reference level of the compander is programmable in three steps from 0.5VRMS
to 2VRMS. For a proper behavior of the compression circuit it is mandatory to have at a 0dB
input signal exactly the programmed reference level after the InGain-stage. E.g. at a
configured reference-level of 0.5VRMS the output of the InGain stage has to have also
0.5VRMS at 0dB source-signal (Usually the 0dB for CD is defined as the maximum possible
signal-level). To adapt the external level to the internal reference level the programmable
attenuation in the differential stages and the InGain can be used.
Figure 17. Compander block diagram
SOFT STEP VOLUME
INL
INL
OUTL
OUTL
INR
INR
OUTR
OUTR
8 Bit
IIC-BUS
VOLUME
CONTROL
8 Bit
6 Bit
ADDER
CLKATT
CLKREL
STEREO FULL
WAVE RECTIFIER
LIN
ANTI-CLIP
ENABLE
D
A
50Hz LOW-PASS
RIN
+
LOG
AMPL
+
AM
MPIN
CLPIN
INPUT
SELECT
D00AU1147
4.10.1
Anti-clipping
In a second application the compander-circuit can be used for a anti-clipping or limiting
function. In this case one of the dedicated inputs (AM or MPin) is connected directly to the
clip-detector of the power-amplifier. if no clipping is detected, the open-collector output of
the power-amplifier is highohmic and the input-voltage of the rectifier is VREF. The level
detector interprets this as a very small signal and reacts with the maximum programmed
compander gain. In the application this gain has to be compensated by decreasing the
26/71
TDA7402
Audioprocessor part
volume with the same value in order to get the desired output-level. In clipping situation the
open collector current generates a voltage drop at the rectifier input, which forces the
compander to decrease the gain until the clipping disappears.
It is even possible to run the compression mode and the anti-clipping mode in parallel. In
this case the maximum compander gain should be set to 29dB.
4.10.2
Characteristic
To achieve the desired compression characteristic like shown below the volume has to be
decreased by 4dB.
Figure 18. Compander characteristic
0
-8dB
-10
2:1
Output Level
-20
-38dB
dB
-30
15dB
-40
-50
-60
0
-10
-20
-30
Input Level
4.10.3
-40
-50
-60
dB
I²C bus timing
While the compander is working, a volume word coming from this stage is added to the I2C
bus volume word, and the volume is changed with a soft slope between adjacent steps
(softstep stage). As mentioned in the description of this stage, it is not recommended to
change the volume during this slope. To avoid this while the compander is working and the
volume has to be changed, the compander hold-bit is implemented (Bit 7 in the subaddress
byte). The recommended timing for changing the volume during compander ON is the
following:
1.
Set the compander hold bit
2.
Wait the actual softstep time
3.
Change the volume
4.
Reset the compander hold bit
The softstep-times are in compander ON condition automatically adapted to the attack time
of the compander. In the following table the related SoftStep-times are shown:
Table 6.
Attack times vs soft-step times
Attack time
SoftStep time
6ms
0.16ms
12ms
0.32ms
24ms
0.64ms
48ms
1.28ms
27/71
Audioprocessor part
4.11
TDA7402
AC coupling
In some applications additional signal manipulations are desired, for example surround
sound or more band equalizing. For this purpose an AC coupling is placed before the
speaker attenuators, which can be activated or internally shorted by the I2C bus. In short
condition the input signal of the speaker attenuator is available at the AC outputs. The input
impedance of this AC Inputs is 50kΩ.
4.12
Output selector
The output-selector allows to connect the main- or the second-source to the front, rear and
subwoofer speaker attenuator, respectively. As an example of this programming the device
is able to connect via software the main source to the back (rear) and the second source to
the front (see Figure 17). In addition to this stage allows to setup different applications by
I2C bus programming. Three examples are given in Figure 18, 19, and 20.
Figure 19. Output selector
ACOUT
MAIN SOURCE
ACINF
ACINR SWIN
SPEAKER FRONT
VOICE BAND
BANDPASS
LEFT CHANNEL
SPEAKER REAR
25K
MS MONO
50K
50K
50K
MAIN SOURCE 25K
RIGHT CHANNEL
LOWPASS
SPEAKER SUBWOOFER
SECOND SOURCE
25K
SEC.S MONO
OFF/ON FC
25K
LEFT CHANNEL
SECOND SOURCE
28/71
D00AU1155
TDA7402
4.13
Audioprocessor part
Subwoofer
Several different applications are possible with the subwoofer circuit:
1.
2.
Subwoofer filter OFF
a)
Main source stereo (AC coupled)
b)
Second source stereo (DC coupled)
c)
Main source mono differential (DC coupled)
d)
Second source mono-differential (DC coupled)
Subwoofer filter ON
a)
Main source mono differential (DC coupled)
b)
Second source mono differential (DC coupled)
c)
Center speaker mode (filtered mono signal at SWL, unfiltered mono signal at
SWR)
In all applications the phase of the output-signal can be configured to be 0° or 180° . In the
center speaker mode only at the filtered output the phase is changed.
Figure 20. Application 1 using internal highpass and mono low pass filter
PROGRAMMING
5/1xxxxxxx
7/xxxxx1xx
10/xxxx10xx
12/1010xxxx
ACINF
MAIN SOURCE
BASS-FILTER
LEFT CHANNEL
220nF
220nF
ACOUT
ACINR
SWIN
SPEAKER FRONT
VOICE BAND
BANDPASS
SPEAKER REAR
25K
MS MONO
MAIN SOURCE
RIGHT CHANNEL
50K
50K
50K
25K
LOWPASS
SECOND SOURCE
SPEAKER SUBWOOFER
25K
SEC.S MONO
OFF/ON
FC
25K
LEFT CHANNEL
D00AU1156
SECOND SOURCE
29/71
Audioprocessor part
TDA7402
Figure 21. Application 2 using internal highpass and external stereo low pass filter
EXTERNAL
LOWPASS
PROGRAMMING
5/0xxxxxxx
7/xxxxx1xx
10/xxxx11xx
12/1010xxxx
220nF
ACINF
MAIN SOURCE
BASS-FILTER
LEFT CHANNEL
ACOUT
ACINR
SWIN
SPEAKER FRONT
VOICE BAND
BANDPASS
SPEAKER REAR
25K
MS MONO
50K
50K
50K
25K
MAIN SOURCE
RIGHT CHANNEL
LOWPASS
SPEAKER SUBWOOFER
SECOND SOURCE
25K
SEC.S MONO
OFF/ON FC
25K
LEFT CHANNEL
D00AU1157
SECOND SOURCE
Figure 22. Application 3 using pure external filtering (e.g. DSP)
EXTERNAL
FILTERING
PROGRAMMING
5/1xxxxxxx
7/xxxxx0xx
10/xxxx11xx
12/1010xxxx
MAIN SOURCE
BASS-FILTER
LEFT CHANNEL
220nF
220nF
220nF
ACINF
ACOUT
ACINR
220nF
SWIN
SPEAKER FRONT
VOICE BAND
BANDPASS
SPEAKER REAR
25K
MS MONO
MAIN SOURCE
RIGHT CHANNEL
50K
50K
50K
25K
LOWPASS
SECOND SOURCE
SPEAKER SUBWOOFER
25K
SEC.S MONO
OFF/ON FC
25K
LEFT CHANNEL
D00AU1163
SECOND SOURCE
4.14
Speaker attenuator and mixing
A mixing-stage is placed after each speaker attenuator and can be set independly to mixing
mode. Having a full volume for the mix signal the stage offers a wide flexibility to adapt the
mixing levels.
30/71
TDA7402
Audioprocessor part
Figure 23. Output selector
FRONT
VOLUME
+15/-79dB
1dB Step
1
OUTF
1
OUTR
25K
FROM OUTPUT
SELECTOR
REAR
FROM MIXING
SELECTOR
VOLUME
+15/-79dB
1dB Step
VOLUME
+15/-79dB
1dB Step
25K
25K
25K
D00AU1164
4.15
Audioprocessor testing
During the testmode, which can be activated by setting bit D0 of the stereo decoder testing
byte and the audioprocessor testing byte, several internal signals are available at the FD2R
pin. During this mode the input resistance of 100kOhm is disconnected from the pin. The
internal signals available are shown in the data byte specification.
31/71
Stereo decoder part
TDA7402
5
Stereo decoder part
5.1
Features:
5.2
●
No external components necessary
●
PLL with adjustment free, fully integrated VCO
●
Automatic pilot dependent MONO/STEREO switching
●
Very high suppression of intermodulation and interference
●
Programmable roll off compensation
●
Dedicated RDS-softmute
●
Highcut and stereo blend-characterisctics programmable in a wide range
●
FM/AM noiseblanker with several threshold controls
●
Multipath-detector with programmable internal/external influence
●
I2C-bus control of all necessary functions
Electrical characteristics
VS = 9V, de-emphasis time constant = 50µs, MPX input voltage VMPX = 500mV (75kHz
deviation), modulation frequency = 1kHz, input gain = 6dB, Tamb = 27°C, unless otherwise
specified.
Table 7.
Electrical characteristics
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
0.5
1.25
Vrms
Vin
MPX input level
Rin
Input resistance
70
100
130
kΩ
Gmin
Min. input gain
1.5
3.5
4.5
dB
Gmax
Max. input gain
8.5
11
12.5
dB
Gstep
Step resolution
1.75
2.5
3.25
dB
SVRR
Supply voltage ripple rejection
Input gain = 3.5dB
Vripple = 100mV, f = 1kHz
30
55
dB
50
dB
a
Max. channel separation
THD
Total harmonic distortion
fin=1kHz, mono
S+N
N
Signal plus noise to noise ratio
A-weighted, S = 2Vrms
80
91
0.02
0.3
%
dB
Mono/Stereo-switch
VPTHST1
Pilot threshold voltage
for stereo, PTH = 1
10
15
25
mV
VPTHST0
Pilot threshold voltage
for stereo, PTH = 0
15
25
35
mV
VPTHMO1
Pilot threshold voltage
for mono, PTH = 1
7
12
17
mV
VPTHMO0
Pilot threshold voltage
for mono, PTH = 0
10
19
25
mV
PLL
Δf/f
32/71
Capture range
0.5
%
TDA7402
Table 7.
Symbol
Stereo decoder part
Electrical characteristics (continued)
Parameter
Test condition
Min.
Typ.
Max.
Unit
VLEVEL >> VHCH
25
50
75
µs
VLEVEL >> VHCH
44
62.5
80
µs
VLEVEL >> VHCH
50
75
100
µs
VLEVEL >> VHCH
70
100
130
µs
De-emphasis and highcut
τDeempFM De-emphasis timeconstants FM
MFM
Highcut timeconstant multiplier FM
τDeempAM De-emphasis timeconstants AM
MAM
REF5V
Highcut timeconstant multiplier AM
VLEVEL << VHCL
3
VLEVEL >> VHCH
37.5
µs
VLEVEL >> VHCH
47
µs
VLEVEL >> VHCH
56
µs
VLEVEL >> VHCH
75
µs
VLEVEL << VHCL
3.7
Internal reference voltage
4.7
5
5.3
V
Lmin
min. LEVEL gain
-1
0
1
dB
Lmaxs
max. LEVEL gain
5
6
7
dB
LGstep
LEVEL gain step resolution
see section 2.7
0.2
0.4
0.6
dB
VSBLmin
Min. voltage for mono
see section 2.8
17
20
23
%REF
5V
VSBLmax
Max. voltage for mono
see section 2.8
62
70
78
%REF
5V
VSBLstep
Step resolution
see section 2.8
1.6
3.3
5.0
%REF
5V
VHCHmin Min. voltage for NO highcut
see section 2.9
37
42
47
%REF
5V
VHCHmax Max. voltage for NO highcut
see section 2.9
58
66
74
%REF
5V
VHCHstep Step resolution
see section 2.9
4.2
8.4
12.6
%REF
5V
VHCLmin
Min. voltage for FULL high cut
see section 2.9
15
17
19
%VHCH
VHCLmax Max. voltage for FULL high cut
see section 2.9
29
33
37
%VHCH
VHCLstep Step resolution
see section 2.9
2.1
4.2
6.3
%REF
5V
40
50
dB
Carrier and harmonic suppression at the output
α19
Pilot signal f=19kHz
α38
Subcarrier f=38kHz
75
dB
α57
Subcarrier f=57kHz
62
dB
α76
Subcarrier f=76kHz
90
dB
33/71
Stereo decoder part
Table 7.
Symbol
TDA7402
Electrical characteristics (continued)
Parameter
Test condition
Min.
Typ.
Max.
Unit
VLEVEL >> VHCH
25
50
75
µs
VLEVEL >> VHCH
44
62.5
80
µs
VLEVEL >> VHCH
50
75
100
µs
VLEVEL >> VHCH
70
100
130
µs
De-emphasis and highcut
τDeempFM De-emphasis timeconstants FM
MFM
Highcut timeconstant multiplier FM
τDeempAM De-emphasis timeconstants AM
MAM
REF5V
Highcut timeconstant multiplier AM
VLEVEL << VHCL
3
VLEVEL >> VHCH
37.5
µs
VLEVEL >> VHCH
47
µs
VLEVEL >> VHCH
56
µs
VLEVEL >> VHCH
75
µs
VLEVEL << VHCL
3.7
Internal reference voltage
4.7
5
5.3
V
Lmin
min. LEVEL gain
-1
0
1
dB
Lmaxs
max. LEVEL gain
5
6
7
dB
LGstep
LEVEL gain step resolution
see section 2.7
0.2
0.4
0.6
dB
VSBLmin
Min. voltage for mono
see section 2.8
17
20
23
%REF
5V
VSBLmax
Max. voltage for mono
see section 2.8
62
70
78
%REF
5V
VSBLstep
Step resolution
see section 2.8
1.6
3.3
5.0
%REF
5V
VHCHmin Min. voltage for NO highcut
see section 2.9
37
42
47
%REF
5V
VHCHmax Max. voltage for NO highcut
see section 2.9
58
66
74
%REF
5V
VHCHstep Step resolution
see section 2.9
4.2
8.4
12.6
%REF
5V
VHCLmin
Min. voltage for FULL high cut
see section 2.9
15
17
19
%VHCH
VHCLmax Max. voltage for FULL high cut
see section 2.9
29
33
37
%VHCH
VHCLstep Step resolution
see section 2.9
2.1
4.2
6.3
%REF
5V
40
50
dB
Carrier and harmonic suppression at the output
α19
Pilot signal f=19kHz
α38
Subcarrier f=38kHz
75
dB
α57
Subcarrier f=57kHz
62
dB
α76
Subcarrier f=76kHz
90
dB
34/71
TDA7402
Table 7.
Symbol
Stereo decoder part
Electrical characteristics (continued)
Parameter
Test condition
Min.
Typ.
Max.
Unit
Intermodulation (Note 2.3.1)
α2
fmod=10kHz, fspur=1kHz
65
dB
α3
fmod=13kHz, fspur=1kHz
75
dB
70
dB
75
dB
Traffic Radio (Note 2.3.2)
α57
Signal f=57kHz
SCA - Subsidiary Communications Authorization (Note 2.3.3)
α67
Signal f = 67kHz
ACI - Adjacent Channel Interference (Note 2.3.4)
α114
Signal f=114kHz
95
dB
α190
Signal f=190kHz
84
dB
5.3
Notes about the characteristics
5.3.1
Intermodulation suppression
V O ( signal ) ( at1kHz )
α2 = ---------------------------------------------------------------- ;f s = ( 2 ⋅ 10kHz ) – 19kHz
V O ( spurious ) ( at1kHz )
V O ( signal ) ( at1kHz )
α3 = ---------------------------------------------------------------- ;f s = ( 3 ⋅ 13kHz ) – 38kHz
V O ( spurious ) ( at1kHz )
measured with: 91% pilot signal; fm = 10kHz or 13kHz.
5.3.2
Traffic radio (V.F.) suppression
V O ( signal ) ( at1kHz )
α57 ( V.W.F ) = ---------------------------------------------------------------------------------------V O ( spurious ) ( at1kHz ± 23kHz )
measured with: 91% stereo signal; 9% pilot signal; fm=1kHz; 5% subcarrier
(f=57kHz, fm=23Hz AM, m=60%)
5.3.3
SCA (subsidiary communications authorization)
V O ( signal ) ( at1kHz )
α67 = ---------------------------------------------------------------- ;f s = ( 2 ⋅ 38kHz ) – 67kHz
V O ( spurious ) ( at1kHz )
measured with: 81% mono signal; 9% pilot signal; fm=1kHz; 10%SCA - subcarrier
( fS = 67kHz, unmodulated ).
35/71
Stereo decoder part
5.3.4
TDA7402
ACI (adjacent channel interference)
V O ( signal ) ( at1kHz )
α114 = ---------------------------------------------------------------- ;f s = 110kHz – ( 3 ⋅ 38kHz )
V O ( spurious ) ( at4kHz )
V O ( signal ) ( at1kHz )
α190 = ---------------------------------------------------------------- ;f s = 186kHz – ( 5 ⋅ 38kHz )
V O ( spurious ) ( at4kHz )
measured with: 90% mono signal; 9% pilot signal; fm=1kHz; 1% spurious signal
( fS = 110kHz or 186kHz, unmodulated).
5.4
Noise blanker part
5.4.1
Features:
●
AM and FM mode
●
internal 2nd order 140kHz high-pass filter for MPX path
●
internal rectifier and filters for AM-IF path
●
programmable trigger thresholds
●
trigger threshold dependent on high frequency noise with programmable gain
●
additional circuits for deviation and fieldstrength dependent trigger adjustment
●
4 selectable pulse suppression times for each mode
●
programmable noise rectifier charge/discharge current
All parameters measured in FM mode if not otherwise specified.
Table 8.
Symbol
VTR
VTRNOISE
36/71
Electrical characteristics
Parameter
Trigger threshold (1)
Noise controlled
Trigger threshold
Test condition
meas.with
VPEAK=0.9V
meas.with
VPEAK=1.5V
Min.
Typ.
Max.
Unit
111
30
mVOP
110
35
mVOP
101
40
mVOP
100
45
mVOP
011
50
mVOP
010
55
mVOP
001
60
mVOP
000
65
mVOP
00
260
mVOP
01
220
mVOP
10
180
mVOP
11
140
mVOP
TDA7402
Table 8.
Symbol
VRECT
Stereo decoder part
Electrical characteristics
Parameter
Test condition
Rectifier voltage
Min.
Typ.
Max.
Unit
VMPX=0mV
0.5
0.9
1.3
V
VMPX=50mV, f=150kHz
1.5
1.7
2.1
V
VMPX=200mV, f=150kHz
2
2.5
2.9
V
VRECTDE Deviation dependent
rectifier voltage
V
meas.with
VMPX=500mV
(75kHz dev.)
11
10
01
00
0.5
0.9
1.7
2.5
0.9(off)
1.2
2.0
2.8
1.3
1.5
2.3
3.1
VOP
VOP
VOP
VOP
Fieldstrength
VRECTFS controlled rectifier
voltage
meas.with
VMPX=0mV,
VLEVEL<< VSBL
(fully mono)
11
10
01
00
0.5
0.9
1.7
2.1
0.9(off)
1.4
1.9
2.4
1.3
1.5
2.3
3.1
V
V
V
V
Signal HOLDN in
testmode
00
01
10
11
38
25.5
32
22
µs
µs
µs
µs
Signal HOLDN in
testmode
00
01
10
11
1.2
800
1.0
640
ms
µs
µs
µs
Signal PEAK in
testmode
00
01
10
11
0.3
0.8
1.3
2.0
V/ms
TSFM
TSAM
Suppression pulse duration FM
Suppression pulse duration AM
VRECTAD Noise rectifier discharge
adjustment
J
(2)
SRPEAK
Noise rectifier (2)
charge
Signal PEAK in
testmode
0
1
10
20
mV/µs
VADJMP
Noise rectifier adjustment
through multipath (2)
Signal PEAK in
testmode
00
01
10
11
0.3
0.5
0.7
0.9
V/ms
RAMIF
AM IF Input resistance
35
GAMIF,min min. gain AM IF
GAMIF,max max. gain AM IF
Signal AM-RECTIFIER in
Testmode
GAMIF,step step gain AM IF
fAMIF,min min. fc AM IF
fAMIF,max max. fc AM IF
Signal AM-RECTIFIER in
Testmode
50
65
kOhm
6
dB
20
dB
2
dB
14
kHz
56
kHz
1. All thresholds are measured using a pulse with TR = 2 µs, THIGH= 2 µs and TF = 10 µs. The repetition rate must not
increase the PEAK voltage.
2. By design/characterization functionally guaranteed through dedicated test mode structure
37/71
Stereo decoder part
TDA7402
Figure 24. Vn timing diagram
V
in
V
op
DC
T im e
TR
T
T HIGH
F
Figure 25. Trigger threshold vs. VPEAK
V TH
260m V (00)
220m V (01)
18 0m V (10)
14 0m V (11)
M IN . TR IG . T H R ES H OLD
N O ISE C O N T R OLLE D T R IG . TH R ES H O LD
65m V
8 STEPS
30m V
0.9V
V P EA K [V ]
1.5V
Figure 26. Deviation controlled trigger adjustment
VP E A K
[V
OP
]
00
2 .8
01
2 .0
10
1 .2
0 .9
D etector o ff (11)
20
3 2.5
45
D EV IA TIO N [KH z]
75
Figure 27. Field strength controlled trigger adjustment
VPEAK
MONO
STEREO
» 3V
2.3V (00)
1.8V (01)
1.3V (10)
NOISE
0.9V
ATC_SB OFF (11)
noisy signal
38/71
good signal
E'
TDA7402
Stereo decoder part
5.5
Multipath detector
5.5.1
Features:
●
internal 19kHz band pass filter
●
programmable band pass and rectifier gain
●
selectable internal influence on stereo blend and/or Highcut
Table 9.
Electrical characteristics of multipath detector
Symbol
fCMP
GBPMP
GRECTM
Parameter
Center frequency of
multipath-bandpass
Test Condition
Min.
Typ.
Max.
Unit
Stereo decoder locked
on pilot tone
19
kHz
G1
6
dB
G2
12
dB
G3
16
dB
G4
18
dB
G1
7.6
dB
G2
4.6
dB
G3
0
dB
0.25
0.5
µA
4
mA
Bandpass gain
Rectifier gain
P
ICHMP
Rectifier charge current
IDISMP
Rectifier discharge current
Quality detector
A
Multipath influence factor
00
01
10
11
0.70
0.85
1.00
1.15
39/71
Functional description of stereo decoder
6
TDA7402
Functional description of stereo decoder
Figure 28. Block diagram of stereo decoder
DEEMPHASIS
+ HIGHCUT
FM_L
t=50.62..5.75,100μs
(37.5,47,56,75μs)
FM_R
DEMODULATOR
MPX
100K
INGAIN
INFILTER
3.5 ... 11dB
STEP 2.5dB
LP 80KHz
4.th ORDER
- PLOT CANC
- ROLL-OFF COMP.
- LP 25KHz
AM
5 bits
PLL +
PILOT-DET.
100K
F19
REF 5V
SB CONTROL
VSBL
HC
CONTROL
D
A
F38
VHCCH
VHCCL
STEREO
MPSBINFL
NOISE BLANKER
-
LEVELSB-LP
AM-IF
NOISE
LEVEL INPUT
MPHCINFL
HOLDN
GAIN 0..6dB
MULTIPATH DET.
MPHCOUT
-
LEVEL
LEVELHC-LP
MPSBOUT
QUALITY
DETECTOR
+
D00AU1135
MP-IN
QUAL
MP-OUT
The stereo decoder-part of the A619 (see Figure 28) contains all functions necessary to
demodulate the MPX-signal like pilot tone dependent Mono/Stereo switching as well as
"stereo blend" and "highcut". Adaptations like programmable input gain, roll off
compensation, selectable de-emphasis time constant and a programmable fieldstrength
input allow to use different IF devices.
6.1
Stereo decoder mute
The A619 has a fast and easy to control RDS mute function which is a combination of the
audioprocessor's SoftMute and the high ohmic mute of the stereo decoder. If the stereo
decoder is selected and a SoftMute command is sent (or activated through the SM-pin) the
stereo decoder will be set automatically to the high-ohmic mute condition after the audiosignal has been softmuted. Hence a checking of alternate frequencies could be performed.
Additionally the PLL can be set to "Hold" mode, which disables the PLL input during the
mute time. To release the system from the mute condition simply the unmute command
must be sent: the stereo decoder is unmuted immediately and the audioprocessor is softly
unmuted. Fig. 26 shows the output-signal VO as well as the internal stereo decoder mute
signal. This influence of SoftMute on the stereo decoder mute can be switched off by setting
bit 3 of the SoftMute byte to "0". A stereo decoder mute command (bit 0, stereo decoder
byte set to "1") will also set the stereo decoder independently to the high-ohmic mute state.
If any other source than the stereo decoder is selected the decoder remains muted and the
MPX pin is connected to Vref to avoid any discharge of the coupling capacitor through
leakage currents. No further mute command should be applied.
40/71
TDA7402
Functional description of stereo decoder
Figure 29. Signals during stereo decoder's SoftMute
Figure 30. Signal control via SoftMute pin
PLL-HOLD
INFLUENCE
MP-HOLD
PLL-HOLD
SOFTMUTE
INFLUENCE
STDHMUTE
INFLUENCE
STDHMUTE
SOFTMUTE
INFLUENCE
SOFTMUTE
PIN
IIC-BUS
6.2
SOFTMUTE
MUTED
D00AU1165
InGain + infilter
The InGain stage allows adjustment of the MPX-signal to a magnitude of about 1Vrms
internally, which is the recommended value. The 4th order input filter has a corner frequency
of 80kHz and is used to attenuate spikes and noise, and acts as an anti-aliasing filter for the
following switch capacitor filters.
6.3
Demodulator
In the demodulator block, the left and the right channels are separated from the MPX signal.
In this stage the 19kHz pilot tone is cancelled. To reach a high channel separation the A619
offers an I2C bus programmable roll-off adjustment which is able to compensate for the
lowpass behavior of the tuner section. If the tuner's attenuation at 38kHz is in a range from
7.2% to 31.0%, the A619 needs no external network in front of the MPX-pin. Within this
range, an adjustment to obtain at least 40dB channel separation is possible. The bits for this
adjustment are located together with the fieldstrength adjustment in one byte. This gives the
possibility to perform an optimization step during the production of the car radio, where the
41/71
Functional description of stereo decoder
TDA7402
channel separation and the fieldstrength control are trimmed. The setup of the stereo blend
characteristics which is programmable in a wide range is described in Chapter 6.8.
6.4
De-emphasis and highcut
The de-emphasis lowpass allows to choose a time constant between 37.5 and 100µs. The
highcut control range will be 2 x τDeemp or 2.7 x τDeemp dependent on the selected time
constant (see programming section). The bit D7 of the hightcut-byte will shift timeconstant
and range.
Inside the highcut control range (between VHCH and VHCL) the LEVEL signal is converted
into a 5 bit word which controls the lowpass time constant between τDeemp...3 (3.7) x τDeemp.
Thereby the resolution will remain always 5 bits independently of the absolute voltage
range between the VHCH and VHCL values. In addition the maximum attenuation can be
fixed between 2 and 10dB.
The highcut function can be switched off by I2C bus (bit D7, Highcut byte set to "0").
The setup of the highcut characteristics is described in Chapter 6.9.
6.5
PLL and pilot tone detector
The PLL has the task to lock on the 19kHz pilot tone during a stereo transmission to allow a
correct demodulation. The included pilot tone-detector enables the demodulation if the pilot
tone reaches the selected pilot tone threshold VPTHST. Two different thresholds are
available. The detector output (signal STEREO, see the Block diagram) can be checked by
reading the status byte of the A619 via I2C-bus. During a Softmute the PLL can be set into
"Hold"-mode which freezes the PLL's state (bit D4, Softmute byte). After releasing the
Softmute the PLL will again follow the input signal only by correcting the phase error.
6.6
Field strength control
The fieldstrength input is used to control the highcut and the stereo blend function. In
addition the signal can be also used to control the noiseblanker thresholds and as input for
the multipath detector. These additional functions are described in sections 6.3 and 7.
6.7
EVEL input and gain
To suppress undesired high frequency modulation on the highcut- and stereo blend-control
signal the LEVEL signal is lowpass filtered firstly. The filter is a combination of a 1st order
RC lowpass at 53kHz (working as anti-aliasing filter) and a 1st-order switched capacitor
lowpass at 2.2kHz. The second stage is a programmable gain stage to adapt the LEVEL
signal internally to different IF devices (see Testmode section 5: LEVELHCC). The gain is
widely programmable in 16 steps from 0dB to 6dB (step=0.4dB). These 4 bits are located
together with the Roll-Off bits in the "Stereo decoder adjustment" byte to simplify a possible
adjustment during the production of the car radio. This signal controls directly the Highcut
stage whereas the signal is filtered again (fc=100Hz) before the stereo blend stage
(see Figure 35).
42/71
TDA7402
6.8
Functional description of stereo decoder
Stereo blend control
The stereo blend control block converts the internal LEVEL voltage (LEVELSB) into an
demodulator compatible analog signal which is used to control the channel separation
between 0dB and the maximum separation. Internally this control range has a fixed upper
limit which is the internal reference voltage REF5V. The lower limit can be programmed
between 20 and 70% of REF5V in 3.3% steps (see Figure 31 and 32).
To adjust the external LEVEL voltage to the internal range two values must be defined: the
LEVEL gain LG and VSBL (see Figure 32). At the point of full channel separation the
external level signal has to be amplified that internally it becomes equal to REF5V. The
second point (e.g. 10dB channel sep.) is then adjusted with the VSBL voltage.
Figure 31. Internal stereo blend characteristics
The gain can be programmed through 4 bits in the "Stereo decoder adjustment" byte. All
necessary internal reference voltages like REF5V are derived from a bandgap circuit.
Therefore they have a temperature co-efficient near zero.
Figure 32. Relation between internal and external LEVEL voltages for setup of
stereo blend
INTERNAL
VOLTAGES
INTERNAL
VOLTAGES
SETUP OF VST
SETUP OF VMO
LEVEL INTERN
REF 5V
70%
LEVEL
VSBL
VSBL
VMO
6.9
LEVEL INTERN
REF 5V
VST
20%
t
FIELDSTRENGHT VOLTAGE
VMO
D00AU1168
VST
t
FIELDSTRENGHT VOLTAGE
Highcut control
The highcut control set-up is similar to the stereo blend control set up : the starting point
VHCH can be set with 2 bits to be 42, 50, 58 or 66% of REF5V whereas the range can be
set to be 17, 22, 28 or 33% of VHCH (see Figure 33).
43/71
Functional description of stereo decoder
TDA7402
Figure 33. Highcut characteristics
LOWPASS
TIME CONSTANT
3.7•τ'Deemp
3•τDeemp
DEEMPHASIS SHIFT ON
OFF
τDeemp
τ'Deemp
VHCL
D00AU1169
44/71
VHCH
FIELDSTRENGHT
TDA7402
7
Functional description of the noise blanker
Functional description of the noise blanker
In the automotive environment the MPX-signal as well as the AM signal is disturbed by
spikes produced by the ignition and other radiating sources like the wiper motor. The aim of
the noiseblanker part is to cancel the audible influence of the spikes. Therefore the output of
the stereo decoder is held at the actual voltage for a time between 22 and 38µs in FM (370
and 645µs in AM mode). The block diagram of the noise blanker is given in Figure 34.
Figure 34. Block diagram of the noise blanker
AM/FM
AMIF
MPX
RECTIFIER +
14-56KHz LPF
(1st. order)
140KHz HPF
(1st. order)
RECTIFIER
RECT
+
140KHz HPF
(2nd. order)
+
MONOFLOP
-
FM: 22 to 40μs
AM: 370 to 6400μs
HOLDN
VTH
PEAK
THRESHOLD
GENERATOR
INTEGRATOR
DISCHARGE
CONTROL
MPOUT
+
ADDITIONAL
THRESHOLD
CONTROL
D00AU1132
In a first stage the spikes must be detected but to avoid a wrong triggering on high
frequency (white) noise a complex trigger control is implemented. Behind the trigger stage a
pulse former generates the "blanking"pulse.
7.1
Trigger path FM
The incoming MPX signal is highpass-filtered, amplified and rectified. This second order
highpass filter has a corner-frequency of 140kHz. The rectified signal, RECT, is integrated
(lowpass filtered) to generate a signal called PEAK. The DC-charge/discharge behaviour
can be adjusted as well as the transient behaviour (MP discharge control). Also noise with a
frequency 140kHz increases the PEAK voltage. The PEAK voltage is fed to a threshold
generator, which adds to the PEAK voltage a DC dependent threshold VTH. Both signals,
RECT and PEAK+VTH are fed to a comparator which triggers a re-triggerable monoflop.
The monoflop's output activates the sample and hold circuits in the signalpath for the
selected duration.
7.2
Noise controlled threshold adjustment (NCT)
There are mainly two independent possibilities for programming the trigger threshold:
1.
the low threshold in 8 steps (bits D1 to D3 of the noiseblanker byte I)
2.
and the noise adjusted threshold in 4 steps (bits D4 and D5 of the noiseblanker byte I,
see Figure 21).
The low threshold is activ in combination with a good MPX signal without noise; the PEAK
voltage is less than 1V. The sensitivity in this operation is high.
If the MPX signal is noisy (low fieldstrength) the PEAK voltage increases due to the higher
noise, which is also rectified. With increasing of the PEAK voltage the trigger threshold
increases, too. This gain is programmable in 4 steps (see Figure 25).
45/71
Functional description of the noise blanker
7.3
Additional threshold control mechanism
7.3.1
Automatic threshold control by the stereo blend voltage
TDA7402
Besides the noise controlled threshold adjustment there is an additional possibility for
influencing the trigger threshold which depends on the stereo blend control.
The point where the MPX signal starts to become noisy is fixed by the RF part. Therefore
also the starting point of the normal noise-controlled trigger adjustment is fixed (Figure 27).
In some cases the behavior of the noiseblanker can be improved by increasing the threshold
even in a region of higher fieldstrength. Sometimes a wrong triggering occurs for the MPX
signal often shows distortion in this range which can be avoided even if using a low
threshold. Because of the overlap of this range and the range of the stereo/mono transition it
can be controlled by stereo blend. This increase of the threshold is programmable in 3 steps
or switched off.
7.3.2
Over deviation detector
If the system is tuned to stations with a high deviation the noiseblanker can trigger on the
higher frequencies of the modulation or distortion. To avoid this behavior, which causes
audible noise in the output signal, the noiseblanker offers a deviation-dependent threshold
adjustment. By rectifying the MPX signal a further signal representing the actual deviation is
obtained. It is used to increase the PEAK voltage. Offset and gain of this circuit are
programmable in 3 steps with the bits D6 and D7 of the noiseblanker byte I (bit combination
'00' turns off the detector, see Figure 26).
7.3.3
Multipath level
To react on high repetitive spikes caused by a multipath-situation, the discharge time of the
PEAK voltage can be decreased depending on the voltage-level at pin MPout. The A619
offers a linear as well as a threshold driven control. The linear influence of the multipath level
on the PEAK-signal (D7 of multipath control byte) gives a discharge slewrate of 1V/ms(1) .
The second possibility is to activate the threshold driven discharge which switches on the
18kOhm discharge if the multipath level is below 2.5V (D7 of noiseblanker byte II byte).
(1)
7.3.4
The slewrate is measured with RDischarge=infinite and VMPout=2.5V
AM mode of the noiseblanker
The A619 noiseblanker is also suitable for AM noise cancelling. The detector uses in AM
mode the 450kHz unfiltered IF output of the tuner for spike detection. A combination of
programmable gain stage and lowpass filter forms an envelope detector which drives the
noiseblanker's input via a 120kHz 1st order highpass. In order to blank the whole spike in
AM mode the hold-times of the sample and hold circuit are much longer then in FM (640µs
to 1.2ms). All threshold controls can be used like in FM mode.
46/71
TDA7402
8
Functional description of the multipath detector
Functional description of the multipath detector
Using the multipath detector the audible effects of a multipath condition can be minimized. A
multipath condition is detected by rectifying the spectrum around 19kHz in the fieldstrength
signal. An external capacitor is used to define the attack and decay times for the stereo
blend (see block diagram, Figure 34). Due to the very small charge currents this capacitor
should be a low leakage current type (e.g ceramic). Using this configuration an adaptation to
the user's requirement is possible without effecting the "normal" fieldstrength input (level) for
the stereo decoder. This application is given in Figure 34. Another (internal) time constant is
used to control the Highcut through the multipath detector
Selecting the "internal influence" in the configuration byte the stereo-blend and/or the
highcut is automatically invoked during a multipath condition according to the voltage
appearing at the MP_OUT pin.
Figure 35. Block diagram of the multipath detector
VDD
=
High-Cut-Infl.
Attach<500μs
Decay=2/10ms
to HCC
INT.
INFLUENCE
LOWPASS
100Hz
LEVEL
LOWPASS
53KHz
to SB
LOWPASS
2.2KHz
VDD
=
SHIFT
0 ... 1.5V
CHARGE
0.25μA/0.5μA
VDD
INT.
INFLUENCE
=
300μA
Stereoblend-Infl.
FAST
CHARGE
Attach=1ms
Decay=4/8s
MP HOLD
MP_OUT
MP_IN
8.1
BANDPASS
19KHz
RECTIFIER
GAIN 2 bits
GAIN 2 bits
470nF
D00AU1166
Quality detector
The A619 offers a quality detector output which gives a voltage representing the FM
reception conditions. To calculate this voltage the MPX-noise and the multipath-detector
output are summed according to the following formula :
VQual = 1.6 (VNoise-0.8 V)+ a (REF5V-VMpout).
The noise-signal is the PEAK signal without additional influences (see the noiseblanker
description). The factor 'a' can by programmed to 0.7 .... 1.15. The output is a low
impedance output able to drive external circuitry as well as simply fed to an AD converter for
RDS applications.
47/71
Functional description of the multipath detector
8.2
TDA7402
Testmode
During the testmode, which can be activated by setting bit D0 and bit D1 of the stereo
decoder testing byte, several internal signals are available at the FD2R+ pin. During this
mode the input resistance of 100kOhm is disconnected from the pin. The internal signals
available are shown in the Data byte specification.
8.3
Dual MPX usage
8.3.1
Feature description
The A619 is able to support a twin tuner concept via the Dual MPX Mode. In this
configuration the MPX pin and the MD2G pin are acting as MPX1 and MPX2 inputs. The DC
voltage at the MD2 pin controls whether one or both MPX signals are used to decode the
stereo FM signal. It is designed as a window comparator with the characteristic shown in
Figure 3 (Please note that the thresholds have a hysteresis of 500mV).
In this mode the stereo decoder high ohmic-mute mutes both inputs in parallel.
Figure 36. Dual MPX input diagram
MPX/
MPX1
1
100K
40K
INGAIN
3.5...11dB
step 2.5dB
40K
MD2G/
MPX2
1
100K
MD2/
CONTROL
1
CONTROL
CIRCUITRY
D00AU1167
8.3.2
Configuration
The Dual MPX mode can be easily configured by setting bit 3 of subaddress 30 to LOW (see
Byte 30 description and application diagram of Figure 38).
48/71
I2C bus interface
TDA7402
9
I2C bus interface
9.1
Interface protocol
●
The interface protocol comprises:
●
a start condition (S)
●
a chip address byte (the LSB bit determines read / write transmission)
●
a subaddress byte
●
a sequence of data (N-bytes + acknowledge)
●
a stop condition (P)
CHIP ADDRESS
MSB
S
1
0
SUBADDRESS
LSB
0
0
1
1
0
R/W
MSB
ACK
C
AZ
DATA 1....DATA n
LSB
I
A
A
A
A
A
MSB
ACK
LSB
DATA
ACK
P
S = Start
R/W = "0" -> Receive-Mode (Chip could be programmed by µP)
"1" -> Transmission-Mode (Data could be received by µP)
ACK = Acknowledge
P = Stop
Max clock speed 500kbits/s
9.2
Auto increment
If bit I in the subaddress byte is set to "1", the autoincrement of the subaddress is enabled.
9.3
Transmitted data (send mode)
Table 10.
Transmitted data (send mode)
MSB
X
LSB
X
X
X
X
P
ST
SM
SM = Soft mute activated
ST = Stereo
P = Pause
X = Not Used
The transmitted data is automatically updated after each ACK.
Transmission can be repeated without new chipaddress.
A Power-On-Reset is invoked if the Supply voltage is below than 3.5V. After that the
following data is written automatically into the registers of all subaddresses :
Table 11.
Reset condition
MSB
1
LSB
1
1
1
1
1
1
0
The programming after POR is marked bold-face / underlined in the programming tables.
With this programming all the outputs are muted to VREF (VOUT= VDD/2).
49/71
I2C bus interface
9.4
TDA7402
Subaddress (receive mode)
Table 12.
Subaddress (receive mode)
MSB
LSB
Function
I2
I1
I0
A4
A3
A2
A1
A0
0
1
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
50/71
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Compander hold
off
on
AutoZero remain
off
on
Auto Increment Mode
off
on
Subaddress
Main Source Selector
Main Loudness
Volume
Treble
Bass
Mixing Programming
SoftMute
Voice-Band
Second Source Selector
Second Source Loudness
Subwoofer Config. / Bass
Compander
Configuration Audioprocessor I
Configuration Audioprocessor II
Subwoofer attenuator L
Subwoofer attenuator R
Speaker attenuator LF
Speaker attenuator RF
Speaker attenuator LR
Speaker attenuator RR
Mixing Level Control
Testing Audioprocessor
stereo decoder
Noise-Blanker I
Noise-Blanker II
AM / AM-Noiseblanker
High-Cut Control
Fieldstr. & Quality
Multipath-Detector
stereo decoder Adjustment
Configuration stereo decoder
Testing Sterodecoder
I2C bus interface
TDA7402
9.5
Data byte specification
The status after power on reset is marked bold face / underlined in the programming tables.
Table 13.
Main selector (0)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
0
0
0
0
1
1
1
1
0
0
:
1
1
0
0
:
1
1
0
0
:
1
1
D1
0
0
1
1
0
0
1
1
D0
0
1
0
1
0
1
0
1
Source selector
FD1 / SE2
SE3
FD2
SE1
MD2
MD1 / SE4
stereo decoder
AM
Input gain
0dB
1dB
:
14dB
15dB
0
1
:
0
1
Mute
off
on
0
1
Table 14.
Main loudness (1)
MSB
LSB
Function
D7
D6
0
0
1
1
0
1
D5
0
1
0
1
D4
D3
D2
D1
D0
0
0
:
0
0
:
1
:
0
0
:
1
1
:
0
:
0
0
:
1
1
:
0
:
0
0
:
1
1
:
1
:
0
1
:
0
1
:
1
:
Attenuation
0 dB
-1 dB
:
-14 dB
-15 dB
:
-19 dB
not allowed
Center frequency
200Hz
400Hz
600Hz
800Hz
Loudness order
First order
Second order
51/71
I2C bus interface
TDA7402
Table 15.
Volume (2)
MSB
LSB
Attenuation
Note:
D7
D6
D5
D4
D3
D2
D1
D0
0
0
:
0
0
0
:
0
0
0
:
1
1
0
0
:
0
0
0
:
0
1
1
:
1
1
0
0
:
0
0
0
:
1
0
0
:
0
0
0
0
:
1
1
1
:
1
0
0
:
1
1
0
0
:
1
1
1
:
1
0
0
:
1
1
0
0
:
0
0
0
:
1
0
0
:
1
1
0
0
:
0
0
1
:
1
0
0
:
1
1
0
1
:
0
1
0
:
1
0
1
:
0
1
Gain/attenuation
(+32.0dB)
(+31.5dB)
:
+20 .0dB
+19.5dB
+19.0dB
:
+0.5dB
0.0dB
-0.5dB
:
-79.0dB
-79.5dB
It is not recommended to use a gain more than 20dB for system performance reason. In
general, the maximum gain should be limited by software to the maximum value, which is
needed for the system.
Table 16.
Treble filter (3)
MSB
LSB
Function
D7
D6
0
0
1
1
0
1
52/71
D5
0
1
0
1
D4
D3
D2
D1
D0
0
0
:
0
0
1
1
:
1
1
0
0
:
1
1
1
1
:
0
0
0
0
:
1
1
1
1
:
0
0
0
0
:
1
1
1
1
:
0
0
0
1
:
0
1
1
0
:
1
0
Treble steps
-15dB
-14dB
:
-1 dB
0 dB
0 dB
+1 dB
:
+14 dB
+15dB
Treble center frequency
10.0 kHz
12.5 kHz
15.0 kHz
17.5 kHz
Subwoofer + center speaker mode
On
Off
I2C bus interface
TDA7402
Table 17.
Bass filter (4)
MSB
LSB
Function
D7
D6
0
0
1
1
D5
D4
D3
D2
D1
D0
0
0
:
0
0
1
1
:
1
1
0
0
:
1
1
1
1
:
0
0
0
0
:
1
1
1
1
:
0
0
0
0
:
1
1
1
1
:
0
0
0
1
:
0
1
1
0
:
1
0
Bass Q-factor
1.0
1.25
1.5
2.0
0
1
0
1
Bass DC-mode
Off
On
0
1
Table 18.
Mixing programming (5)
MSB
D7
LSB
D6
D5
D4
D3
D2
D1
D0
0
1
0
0
1
1
0
1
0
1
Bass steps
-15dB
-14dB
:
-1 dB
0 dB
0 dB
+1 dB
:
+14 dB
+15dB
0
1
0
1
0
1
0
1
0
1
Function
Mixing
Mute
enable
Mixing source
Beep
MD1
MD2
FM mono
Mixing target
Speaker LF off
Speaker LF on
Speaker RF off
Speaker RF on
Speaker LR off
Speaker LR on
Speaker RR off
Speaker RR on
Stereo subw. using internal highpass filter
On
Off
53/71
I2C bus interface
TDA7402
Table 19.
Soft mute (6)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
0
0
1
1
D1
0
1
0
1
D0
0
1
Influence on stereo decoder highohmic mute
on
off
0
1
Influence on pilot detector hold and MP hold
on
off
0
1
Influence on SoftMute
on
off
0
1
0
0
1
1
Beep frequencies
600 Hz
780 Hz
1.56 kHz
2.4 kHz
0
1
0
1
Table 20.
SoftMute
On (Mute)
Off
Mutetime = 0.48ms
Mutetime = 0.96ms
Mutetime = 123ms
Mutetime = 324 ms
Voiceband (7)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
1
0
1
54/71
Voice band low pass enable
Filter off
Filter on
Voice band low pass frequency
3 kHz
6 kHz
Voice band high pass enable
Filter off
Filter on
I2C bus interface
TDA7402
Table 20.
Voiceband (7) (continued)
MSB
LSB
Function
D7
D6
D5
D4
D3
0
0
0
1
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
D2
D1
D0
High pass cut off frequency
90Hz
135Hz
180Hz
215Hz
300Hz
450Hz
600Hz
750Hz
Anti clipping enable
on
off
0
1
Anti clipping input
MP-In
AM
0
1
Table 21.
Second source selector (8)
MSB
LSB
Function
D7
D6
0
0
:
1
1
0
1
D5
0
0
:
1
1
D4
0
0
:
1
1
D3
0
1
:
0
1
D2
D1
D0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Source selector
FD1 / SE2
SE3
FD2
SE1
MD2
MD1 / SE4
stereo decoder
AM
Input gain
0dB
1dB
:
14dB
15dB
Mute
off
on
55/71
I2C bus interface
TDA7402
Table 22.
Second loudness (9)
MSB
LSB
Function
D7
D6
0
0
1
1
D5
D4
D3
D2
D1
D0
0
0
:
0
0
:
1
:
0
0
:
1
1
:
0
:
0
0
:
1
1
:
0
:
0
0
:
1
1
:
1
:
0
1
:
0
1
:
1
:
0
1
0
1
0
1
Table 23.
Attenuation
0 dB
-1 dB
:
-14 dB
-15 dB
:
-19 dB
not allowed
Center frequency
200Hz
400Hz
600Hz
800Hz
Loudness order
First order
Second order
Subwoofer Configuration / Bass (10)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
0
1
0
1
0
1
0
0
0
0
1
1
1
1
56/71
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
D1
D0
0
0
1
1
0
1
0
1
Subwoofer filter
off
80Hz
120Hz
160Hz
Subwoofer outputs
differential (mono)
single ended (stereo)
Subwoofer source
Second source
Main source
Subwoofer phase
180°
0°
Bass center frequency
60Hz
80Hz
70Hz
90Hz
100Hz
130Hz
150Hz
200Hz
I2C bus interface
TDA7402
Table 24.
Compander (11)
MSB
LSB
Function
D7
D6
D5
D4
D3
0
0
1
1
0
0
1
1
0
0
0
0
1
1
1
1
0
0
1
1
D2
D1
D0
0
0
1
1
0
1
0
1
Attack-times
6ms
12ms
24ms
49ms
0
1
0
1
0
1
0
1
Release-times
390ms
780ms
1.17s
1.56s
0
1
0
1
SoftStep-time1)
160µs
320µs
640µs
1.28ms
2.56ms
5.12ms
10.2ms
20.4ms
0
0
1
1
0
1
0
1
Compander max. gain
29dB
19dB
0
1
Note:
Activity / reference level
off
0.5VRMS
1VRMS
2VRMS
The SoftStep times are only programmable while the compander is not in use.
Table 25.
Configuration audioprocessor I (12)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
1
Compander source
Main selector
Second source selector
SoftStep
off
on
57/71
I2C bus interface
TDA7402
Table 25.
Configuration audioprocessor I (12) (continued)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
Main loudness
flat
Filter ON
0
1
Second loudness
flat
Filter ON
0
1
0
0
1
1
0
0
1
1
Front speaker
not allowed
Second source internal coupled
Main source AC coupled
Main source internal coupled
0
1
0
1
Rear speaker
not allowed
Second source internal coupled
Main source AC coupled
Main source internal coupled
0
1
0
1
Table 26.
Configuration audioprocessor II (13)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
0
1
1
0
1
0
0
1
1
58/71
0
1
0
1
0
1
0
1
Pause detector
off
on
Pause ZC window
160mV
80mV
40mV
not allowed
FD1 mode
single ended
differential
FD1 attenuation
-12dB
-6dB
-6dB
0dB
I2C bus interface
TDA7402
Table 26.
Configuration audioprocessor II (13) (continued)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
FD2 attenuation
-6dB
0dB
0
1
MD1 mode
single ended
differential
0
1
Table 27.
Speaker, subwoofer and mixer level-control (14-20)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
1
:
1
1
0
0
:
0
0
:
0
0
0
:
0
0
0
0
:
0
0
:
1
1
0
:
0
0
0
0
:
0
0
:
0
0
0
:
0
0
0
0
:
0
1
:
0
0
1
:
0
0
0
0
:
1
0
:
1
1
1
:
0
0
0
0
:
1
0
:
1
1
1
:
0
0
0
0
:
1
0
:
1
1
1
:
1
0
0
1
:
1
0
:
0
1
+15 dB
:
+1 dB
0 dB
0 dB
-1 dB
:
-15 dB
-16 dB
:
-78 dB
-79 dB
x
1
1
x
x
x
x
x
Mute
The programming of all speaker, subwoofer and mixing level controls are the same.
59/71
I2C bus interface
TDA7402
Table 28.
Testing Audioprocessor (21)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
Audioprocessor testmode
off
on
0
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
Test-multiplexer
Compander log amp. output
Compander low pass output
Compander DAC output
200kHz oscillator
not allowed
not allowed
NB-hold
internal reference
0
1
0
1
0
1
0
1
Compander testmode
off
on
0
1
Clock
external
internal
0
1
AZ function
off
on
0
1
SC-clock
Fast mode
Normal mode
0
1
Note:
This byte is used for testing or evaluation purposes only and must not set to other values
than "11101110" in the application!
Table 29.
Stereo decoder (22)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
0
1
1
0
1
60/71
0
1
0
1
STD unmuted
STD muted
IN-gain 11 dB
IN-gain 8.5 dB
IN-gain 6 dB
IN-gain 3.5 dB
Input AM pin
Input MPX pin
I2C bus interface
TDA7402
Table 29.
Stereo decoder (22) (continued)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
Forced MONO
MONO/STEREO switch automatically
0
1
0
0
1
1
Note:
Pilot threshold HIGH
Pilot threshold LOW
De-emphasis 50µs (37.5µs1)
De-emphasis 62.5µs (46.9µs1)
De-emphasis 75µs (56.3µs1)
De-emphasis 100µs (75µs1)
0
1
0
1
If De-emphasis-Shift enabled (Subaddr.26/Bit7 = 0)
Table 30.
Noise blanker I (23)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Noise blanker off
Noise blanker on
Low threshold 65mV
Low threshold 60mV
Low threshold 55mV
Low threshold 50mV
Low threshold 45mV
Low threshold 40mV
Low threshold 35mV
Low threshold 30mV
Noise controlled threshold 320mV
Noise controlled threshold 260mV
Noise controlled threshold 200mV
Noise controlled threshold 140mV
Overdeviation adjust 2.8V
Overdeviation adjust 2.0V
Overdeviation adjust 1.2V
Overdeviation detector OFF
61/71
I2C bus interface
TDA7402
Table 31.
Noiseblanker II (24)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
0
1
1
0
0
1
1
0
0
1
1
PEAK charge current
low
high
Fieldstrength adjust
2.3V
1.8V
1.3V
OFF
0
1
0
1
Blank Time FM / AM
38µs / 1.2ms
25.5µs / 800µs
32µs / 1.0s
22µs / 640µs
0
1
0
1
Noise rectifier discharge resistor
R = infinite
RDC = 56k
RDC = 33k
RDC = 18k
0
1
0
1
Strong multipath influence on PEAK 18k
off
on (18k discharge if VMPout< 2.5V)
0
1
Table 32.
AM / FM noiseblanker (25)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
0
0
0
1
1
1
1
62/71
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Stereo decoder mode
FM
AM
AM rectifier gain
6dB
8dB
10dB
12dB
14dB
16dB
18dB
20dB
I2C bus interface
TDA7402
Table 32.
AM / FM noiseblanker (25) (continued)
MSB
LSB
Function
D7
1
D6
D5
D4
0
0
1
1
0
1
0
1
D3
D2
D1
D0
Rectifier cut off frequency
14.0kHz
18.5kHz
28.0kHz
56.0kHz
1
Table 33.
must be "1"
High cut (26)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
High cut
off
on
max. high cut
2dB
5dB
7dB
10dB
VHCH to be at
42% REF5V
50% REF5V
58% REF5V
66% REF5V
VHCL to be at
16.7% VHCH
22.2% VHCH
27.8% VHCH
33.3% VHCH
De-emphasis shift
On
Off
63/71
I2C bus interface
TDA7402
Table 34.
Fieldstrength control (27)
MSB
LSB
Function
D7
D6
D5
0
0
1
1
0
0
1
1
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Quality detector co-efficient
a=0.7
a=0.85
a=1.0
a=1.15
0
1
0
1
HCC level shift (only level through MPD)
0.0V
500mV
1.0 V
1.5 V
0
1
0
1
Table 35.
VSBL to be at
20.0% REF5V
23.3% REF5V
26.6% REF5V
30.0% REF5V
33.3% REF5V
36.6% REF5V
40.0% REF5V
43.3% REF5V
46.6% REF5V
50.0% REF5V
53.3% REF5V
56.6% REF5V
60.0% REF5V
63.3% REF5V
66.6% REF5V
70.0% REF5V
Multipath detector (28)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
0
1
1
64/71
0
1
0
1
Fast Load
on
off
Bandpass Gain
6dB
12dB
16dB
18dB
I2C bus interface
TDA7402
Table 35.
Multipath detector (28) (continued)
MSB
LSB
Function
D7
D6
D5
D4
D3
0
0
1
1
0
1
0
1
D2
D1
D0
Rectifier gain
Gain = 7.6dB
Gain = 4.6dB
Gain = 0dB
disabled
Charge current at MP out
0.25µA
0.50µA
0
1
Multipath on high cut decay time
2ms
10ms
0
1
Multipath influence on PEAK discharge
off
-1V/ms
0
1
Table 36.
Stereo decoder adjustment (29)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
:
0
:
0
0
0
0
:
1
:
1
0
0
1
:
0
:
1
0
1
0
:
0
:
1
Roll off compensation
not allowed
7.2%
9.4%
:
13.7%
:
20.2%
1
1
1
:
1
:
1
0
0
0
:
1
:
1
0
0
1
:
0
:
1
0
1
0
:
0
:
1
not allowed
19.6%
21.5%
:
25.3%
:
31.0%
0
0
0
:
1
0
0
0
:
1
0
0
1
:
1
0
1
0
:
1
LEVEL gain
0dB
0.4dB
0.8dB
:
6dB
65/71
I2C bus interface
TDA7402
Table 37.
Stereo decoder configuration (30)
MSB
LSB
Function
D7
D6
D5
D4
D3
D2
D1
D0
0
1
0
1
1
Note:
1
1
1
0
1
Multipath influence on stereo blend
On
Off
1
x
Level input over multipath detector1
On
Off
1
x
0
1
Dual MPX mode
On
Off
1
must be "1"
Using the multipath time-constants for stereo bland and high cut
Table 38.
Testing stereo decoder (31)
LS
B
MSB
D7
D6
D5
D4
D3
D2
D1
0
1
Function
D0
0
1
66/71
Multipath influence on high cut
On
Off
Main testmode
off
on
stereo decoder testmode
off
on
I2C bus interface
TDA7402
Table 38.
Testing stereo decoder (31) (continued)
LS
B
MSB
D7
D6
D5
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
1
1
Note:
D4
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
D3
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
D2
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
D1
Function
D0
Test signals
F228
NB threshold
Level for stereo blend
Pilot magnitude
VHCCL
Pilot threshold
VHCCH
REF5V
HOLDN
NB peak
AM rectifier
VCOCON; VCO control voltage
VSBL
Pilot threshold
Level for high cut
REF5V
Audioprocessor oscillator
Off
On
must be "1"
This byte is used for testing or evaluation purposes only and must not set to other values
than "11111100" in the application!
67/71
Application information
10
TDA7402
Application information
Figure 37. Application diagram (standard configuration)
OUTLR
OUTLF
220nF
SEL
220nF
SER
220nF
FD1L+
220nF
FD1L220nF
FD1R+
220nF
FD1R220nF
FD2L+
220nF
FD2L220nF
FD2R+
220nF
FD2R220nF
AM
220nF
MPX1
470nF
OUTLF
SEL
SER
OUTLR
OUTRF
29
30
1
OUTRR
OUTRF
OUTRR
OUTSWL
OUTSWL
OUTSWR
27
28
OUTSWR
26
OUTSSL
OUTSSL
25
24
44
2
FD1L+
43
3
FD1L-
42
4
FD1R+
41
5
FD1R-
FD2L+
FD2L-
23
6
40
7
39
38
8
37
FD2R+
9
36
FD2R-
10
35
AM
11
34
MPX
33
13
32
MPOUT
31
16
12
AMIF
14
LEVEL
15
MPIN
17
19
18
QUAL
SM
GND
20
OUTSSR
220nF
MD2G
MD2G
220nF
MD2
MD2
220nF
MD1G
MD1G
220nF
MD1
MD1
MUX PAUSE
47nF
MUX
10μF
CREF
ACOUTL
ACOUTL
ACOUTR
SWINR
ACOUTR
220nF
220nF
SWINL
ACINLF
470nF
470nF
ACINLR
ACINRF
ACINRR
22
21
SDA
OUTSSR
VDD
SCL
+ VB1
=
220nF
100nF
- 9
AMIF
LEVEL
MPIN
QUAL
SMUTE
SDA
D00AU1161
SCL
Figure 38. Application diagram (Dual MPX mode)
OUTRF
OUTLF
100nF
SEL
100nF
SER
220nF
FD1L+
220nF
FD1L220nF
FD1R+
220nF
FD1R220nF
FD2L+
220nF
FD2L220nF
FD2R+
220nF
FD2R100nF
AM
100nF
MPX1
470nF
OUTLF
SEL
SER
FD1L+
FD1L-
FD1R+
FD1R-
FD2L+
FD2L-
FD2R+
FD2R-
AM
MPX
MPOUT
OUTLR
OUTRF
29
30
1
OUTRR
OUTLR
OUTRR
28
OUTSWL
OUTSWL
27
OUTSWR
OUTSWR
26
OUTSSL
OUTSSL
25
24
23
2
44
43
3
42
4
41
OUTSSR
MPX2
MD2
40
39
7
38
8
37
9
36
10
35
11
34
33
13
32
31
16
12
AMIF
14
LEVEL
15
MPIN
17
QUAL
19
18
SM
GND
20
MD1G
220nF
MD1
MD1
SDA
SCL
MUX
10μF
CREF
ACOUTL
ACOUTL
ACOUTR
SWINR
SWINL
ACINLF
ACOUTR
220nF
220nF
470nF
ACINLR
ACINRF
ACINRR
VDD
+ VB1
=
100nF
- 9
AMIF
68/71
LEVEL
MPIN
QUAL
SMUTE
SDA
SCL
MUX PAUSE
47nF
22
21
VPX CONTROL
220nF
MD1G
5
6
OUTSSR
100nF
MD2G
D00AU1158
470nF
TDA7402
11
Package information
Package information
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
Figure 39. LQFP44 (10x10) Mechanical data and package dimensions
DIM.
mm
MIN.
inch
TYP.
MAX.
A
MIN.
TYP.
MAX.
1.60
0.0630
0.15 0.0020
0.0059
A1
0.05
A2
1.35
1.40
1.45 0.0531 0.0551 0.0571
b
0.30
0.37
0.45 0.0118 0.0146 0.0177
c
0.09
D
11.80
12.00
12.20 0.4646 0.4724 0.4803
D1
9.80
10.00
10.20 0.3858 0.3937 0.4016
D2
2.00
D3
0.20 0.0035
0.0079
0.0787
8.00
0.3150
E
11.80
12.00
12.20 0.4646 0.4724 0.4803
E1
9.80
10.00
10.20 0.3858 0.3937 0.4016
E2
2.00
0.0787
E3
8.00
0.3150
e
0.80
0.0315
L
L1
K
ccc
0.45
OUTLINE AND
MECHANICAL DATA
0.60
0.75 0.0177
1.00
0.0295
0.0394
3.5˚(min.),7˚(max.)
0.10
0.0039
Note: 1. The size of exposed pad is variable depending of leadframe design pad size. End user should verify “D2” and
“E2” dimensions for each device application.
LQFP44 (10 x 10 x 1.40mm)
Exposed Pad Down
7278839 C
69/71
Revision history
12
TDA7402
Revision history
Table 39.
70/71
Document revision history
Date
Revision
Changes
26-Apr-02
1
Initial release
21-Jun-04
2
Technical migration from ST-PRESS to EDOCS
26-Apr-04
3
Revalidation
26-Apr-06
4
Repair document of typographical errors
23-Mar-07
5
Package change, layout change, text modifications.
TDA7402
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