a
Dual Single-Supply
Audio Operational Amplifier
SSM2135
FEATURES
Excellent Sonic Characteristics
High Output Drive Capability
5.2 nV/√Hz Equivalent Input Noise @ 1 kHz
0.001% THD+N (VO = 2.5 V p-p @ 1 kHz)
3.5 MHz Gain Bandwidth
Unity-Gain Stable
Low Cost
APPLICATIONS
Multimedia Audio Systems
Microphone Preamplifier
Headphone Driver
Differential Line Receiver
Balanced Line Driver
Audio ADC Input Buffer
Audio DAC l-V Converter and Filter
Pseudo-Ground Generator
PIN CONNECTIONS
8-Lead Epoxy DIP
(P-Suffix)
8-Lead Narrow-Body SOIC
(S Suffix)
OUT A
–IN A
V+
SSM2135
OUT B
+IN A
–IN B
V–/GND
+IN B
OUT A
1
8
V+
–IN A
2
7
OUT B
+IN A
3
6
–IN B
V–/GND
4
5
+IN B
SSM2135
under moderate load conditions. Under severe loading, the
SSM2135 still maintains a wide output swing with ultralow
distortion.
GENERAL DESCRIPTION
The SSM2135 Dual Audio Operational Amplifier permits
excellent performance in portable or low power audio systems,
with an operating supply range of +4 V to +36 V or ± 2 V to
± 18 V. The unity gain stable device has very low voltage noise
of 4.7 nV/√Hz, and total harmonic distortion plus noise below
0.01% over normal signal levels and loads. Such characteristics
are enhanced by wide output swing and load drive capability. A
unique output stage* permits output swing approaching the rail
Particularly well suited for computer audio systems and
portable digital audio units, the SSM2135 can perform
preamplification, headphone and speaker driving, and balanced
line driving and receiving. Additionally, the device is ideal for
input signal conditioning in single-supply sigma-delta analogto-digital converter subsystems such as the AD1878/AD1879.
The SSM2135 is available in 8-lead plastic DIP and SOIC
packages, and is guaranteed for operation over the extended
industrial temperature range of –40°C to +85°C.
*Protected by U. S. Patent No. 5,146,181.
FUNCTIONAL BLOCK DIAGRAM
V+
OUT
+IN
9V 9V
–IN
V–/GND
REV. D
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
SSM2135–SPECIFICATIONS
(VS = +5 V, –408C < TA < +858C unless otherwise noted.
Typical specifications apply at TA = +258C.)
Parameter
Symbol
Conditions
AUDIO PERFORMANCE
Voltage Noise Density
Current Noise Density
Signal-To-Noise Ratio
Headroom
Total Harmonic Distortion
en
in
SNR
HR
THD+N
f = 1 kHz
f = 1 kHz
20 Hz to 20 kHz, 0 dBu = 0.775 V rms
Clip Point = 1% THD+N, f = 1 kHz, RL = 10 kΩ
AV = +1, VO = 1 V p-p, f = 1 kHz, 80 kHz LPF
RL = 10 kΩ
RL = 32 Ω
DYNAMIC PERFORMANCE
Slew Rate
Gain Bandwidth Product
Settling Time
SR
GBW
tS
INPUT CHARACTERISTICS
Input Voltage Range
Input Offset Voltage
Input Bias Current
Input Offset Current
Differential Input Impedance
Common-Mode Rejection
Large Signal Voltage Gain
VCM
VOS
IB
IOS
ZIN
CMR
AVO
OUTPUT CHARACTERISTICS
Output Voltage Swing High
VOH
Output Voltage Swing Low
VOL
Short Circuit Current Limit
ISC
POWER SUPPLY
Supply Voltage Range
Power Supply Rejection Ratio
Supply Current
VS
PSRR
ISY
Min
RL = 2 kΩ, TA = +25°C
0.6
to 0.1%, 2 V Step
Typ
nV/√Hz
pA/√Hz
dBu
dBu
0.003
0.005
%
%
0.9
3.5
5.8
V/µs
MHz
µs
0.2
300
0 V ≤ VCM ≤ 4 V, f = dc
0.01 V ≤ VOUT ≤ 3.9 V, RL = 600 Ω
87
2
RL = 100 kΩ
RL = 600 Ω
RL = 100 kΩ
RL = 600 Ω
4.1
3.9
Single Supply
Dual Supply
VS = +4 V to +6 V, f = dc
VOUT = 2.0 V, No Load
VS = +5 V
VS = ± 18 V, VOUT = 0 V, No Load
+4
±2
90
Units
5.2
0.5
121
5.3
0
VOUT = 2 V
VCM = 0 V, VOUT = 2 V
VCM = 0 V, VOUT = 2 V
Max
+4.0
2.0
750
50
4
112
± 30
3.5
3.0
V
V
mV
mV
mA
+36
± 18
V
V
dB
6.0
7.6
mA
mA
120
2.8
3.7
V
mV
nA
nA
MΩ
dB
V/µV
ABSOLUTE MAXIMUM RATINGS
THERMAL CHARACTERISTICS
Supply Voltage
Single Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +36 V
Dual Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 18 V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± VS
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . 10 V
Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Operating Temperature Range . . . . . . . . . . . –40°C to +85°C
Junction Temperature Range (TJ) . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 60 sec) . . . . . . . . . . . . +300°C
Thermal Resistance1
ESD RATINGS
Model
Temperature
Range
Package
Description
SSM2135P
SSM2135S
–40°C to +85°C
–40°C to +85°C
8-Lead Plastic DIP N-8
8-Lead SOIC
SO-8
883 (Human Body) Model . . . . . . . . . . . . . . . . . . . . . . . 1 kV
EIAJ Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 V
8-Lead Plastic DIP
8-Lead SOIC
θJA
θJC
θJA
θJC
103°C/W
43°C/W
158°C/W
43°C/W
θJA is specified for worst case conditions, i.e., θJA is specified for device in
socket for P-DIP and device soldered in circuit board for SOIC package.
1
ORDERING GUIDE
–2–
Package
Option
REV. D
SSM2135
10
+5V
VS = +5V
500µF
+
AV = +1, ƒ = 1kHz
VIN = 1Vp-p
1
RL = 10kΩ
WITH 80kHz FILTER
THD – %
RL
+2.5Vdc
0.1
Figure 1. Test Circuit for Figures 2–4
0.01
0.001
10
100
1k
LOAD RESISTANCE – Ω
10k
Figure 4. THD+N vs. Load (See Test Circuit)
1
VS = +5V
RL = 100kΩ
VOUT = 2.5Vp-p
ƒ = 1kHz
WITH 80kHz FILTER
THD+N – %
0.1
Figure 2. THD+N vs. Amplitude (See Test Circuit; AV = +1,
VS = +5 V, f = 1 kHz, with 80 kHz Low-Pass Filter)
NONINVERTING
INVERTING
0.01
0.001
0
10
20
30
GAIN – dB
40
50
60
Figure 5. THD+N vs. Gain
1
VS = +5V
AV = +1, ƒ = 1kHz
VIN = 1Vp-p
RL = 10kΩ
WITH 80kHz FILTER
THD+N – %
0.1
0.01
Figure 3. THD+N vs. Frequency (See Test Circuit;
AV = +1, VIN = 1 V p-p, with 80 kHz Low-Pass Filter)
0.001
5
10
15
20
25
SUPPLY VOLTAGE – V
Figure 6. THD+N vs. Supply Voltage
REV. D
–3–
30
SSM2135
5
VS = +5V
TA = +25°C
in – pA/ √Hz
4
3
2
1
0
Figure 7. SMPTE Intermodulation Distortion (AV = +1,
VS = +5 V, f = 1 kHz, RL = 10 kΩ)
1
10
100
FREQUENCY – Hz
1k
Figure 10. Current Noise Density vs. Frequency
1s
100
90
10
0%
Figure 8. Input Voltage Noise (20 nV/div)
Figure 11. Frequency Response (AV = +1, VS = +5 V,
VIN = 1 V p-p, RL = 10 kΩ)
30
VS = +5V
TA = +25°C
25
100
90
en – nV/ √Hz
20
15
10
10
0%
5
0
500m V
1
10
100
FREQUENCY – Hz
1µS
1k
Figure 9. Voltage Noise Density vs. Frequency
Figure 12. Square Wave Response (VS = +5 V, AV = +1,
RL = ∞)
–4–
REV. D
SSM2135
60
50
TA = +25 °C
40
20
AV = +100
CLOSED-LOOP GAIN – dB
CHANNEL SEPARATION – dB
VS = +5V
VS = +5V
TA = +25°C
40
0
–20
–40
–60
–80
–100
105
30
20
AV = +10
10
0
AV = +1
–10
–120
–20
10
100
1k
10k
100k
FREQUENCY – Hz
1M
10M
1k
1M
10M
Figure 16. Closed-Loop Gain vs. Frequency
140
100
VS = +5V
VS = +5V
TA = +25 °C
TA = +25° C
0
80
OPEN-LOOP GAIN – dB
100
80
60
40
60
45
GAIN
90
40
PHASE
θm = 57°
20
180
0
20
225
10M
–20
1k
10k
100k
1M
135
PHASE – Degrees
120
0
100
1k
10k
FREQUENCY – Hz
100k
1M
FREQUENCY – Hz
Figure 14. Common-Mode Rejection vs. Frequency
Figure 17. Open-Loop Gain and Phase vs. Frequency
50
140
80
60
–PSRR
RL = 2kΩ
VIN = 100mVp–p
40
OVERSHOOT – %
100
VS = +5V
45
VS = +5V
AV = +1
TA = +25°C
120
PSRR – dB
100k
FREQUENCY – Hz
Figure 13. Crosstalk vs. Frequency (RL = 10 kΩ)
COMMON-MODE REJECTION – dB
10k
+PSRR
40
TA = +25 °C
AV = +1
35
30
NEGATIVE
EDGE
25
20
POSITIVE
EDGE
15
20
10
0
5
0
–20
10
100
1k
10k
FREQUENCY – Hz
100k
0
1M
200
300
400
500
LOAD CAPACITANCE – pF
Figure 15. Power Supply Rejection vs. Frequency
REV. D
100
Figure 18. Small Signal Overshoot vs. Load Capacitance
–5–
SSM2135
40
50
VS = +5V
TA = +25°C
45
VS = +5V
AV = +1
RL = 10k
ƒ = 1kHz
THD+N = 1%
TA = +25°C
35
OUTPUT VOLTAGE – Volts
40
IMPEDANCE – Ω
35
AVCL = +100
30
25
AVCL = +10
20
15
30
25
20
15
10
10
5
5
AVCL = +1
0
0
100
1k
10k
FREQUENCY – Hz
100k
0
1M
15
20
25
30
SUPPLY VOLTAGE – Volts
35
5.0
5
POSITIVE OUTPUT SWING – Volts
3
2
1
2.0
4.5
1.5
+SWING
RL = 2kΩ
4.0
1.0
–SWING
RL = 2kΩ
+SWING
RL = 600Ω
3.5
0.5
–SWING
RL = 600Ω
3.0
0
1
10
40
VS = +5.0V
VS = +5V
TA = +25°C
AV = +1
ƒ = 1kHz
THD+N = 1%
4
100
1k
LOAD RESISTANCE – Ω
10k
–50
–75
100k
–25
0
25
50
75
100
0
125
TEMPERATURE – °C
Figure 20. Maximum Output Voltage vs. Load Resistance
Figure 23. Output Swing vs. Temperature and Load
6
2.0
VS = +5V
VS = +5V
+0.5V ≤ V OUT ≤ +4.0V
RL = 2kΩ
5
TA = +25 °C
AV = +1
1.5
4
SLEW RATE – V/µs
MAXIMUM OUTPUT SWING – Volts
10
Figure 22. Output Swing vs. Supply Voltage
Figure 19. Output Impedance vs. Frequency
MAXIMUM OUTPUT – Volts
5
NEGATIVE OUTPUT SWING – Volts
10
3
2
+SLEW RATE
1.0
–SLEW RATE
0.5
1
0
1k
10k
100k
1M
0
10M
–75
FREQUENCY – Hz
–50
–25
0
25
50
75
100
125
TEMPERATURE – °C
Figure 21. Maximum Output Swing vs. Frequency
Figure 24. Slew Rate vs. Temperature
–6–
REV. D
SSM2135
5
20
VS = +5.0V
VO = 3.9V
18
4
SUPPLY CURRENT – mA
OPEN-LOOP GAIN – V/µV
16
RL = 2kΩ
14
12
RL = 600Ω
10
8
6
VS = ±18V
VS = ±15V
3
VS = +5.0V
2
1
4
2
0
0
–75
–50
–25
0
25
50
75
100
125
–75
–50
–25
TEMPERATURE – °C
0
25
50
75
100
125
TEMPERATURE – °C
Figure 25. Open-Loop Gain vs. Temperature
70
Figure 27. Supply Current vs. Temperature
5
500
4
GBW
60
3
θm
55
2
50
–75
–50
–25
0
25
50
75
100
INPUT BIAS CURRENT – nA
65
GAIN-BANDWIDTH PRODUCT – MHz
PHASE MARGIN – Degrees
VS = +5V
VS = +5.0V
300
VS = ±15V
200
100
1
125
0
–75
TEMPERATURE – °C
–50
–25
0
25
50
75
100
125
TEMPERATURE – °C
Figure 26. Gain Bandwidth Product and Phase Margin vs.
Temperature
Figure 28. Input Bias Current vs. Temperature
The SSM2135 is fully protected from phase reversal for inputs
going to the negative supply rail. However, an internal ESD
protection diodes will turn “on” when either input is forced
more than 0.5 V below the negative rail. Under this condition,
input current in excess of 2 mA may cause erratic output
behavior, in which case a current limiting resistor should be
included in the offending input if phase integrity is required
with excessive input voltages. A 500 Ω or higher series input
resistor will prevent phase inversion even with the input pulled 1
volt below the negative supply.
APPLICATION INFORMATION
The SSM2135 is a low voltage audio amplifier that has
exceptionally low noise and excellent sonic quality even when
driving loads as small as 25 Ω. Designed for single supply use,
the SSM2135’s inputs common-mode and output swing to zero
volts. Thus with a supply voltage at +5 V, both the input and
output will swing from 0 V to +4 V. Because of this, signal
dynamic range can be optimized if the amplifier is biased to a
+2 V reference rather than at half the supply voltage.
The SSM2135 is unity-gain stable, even when driving into a fair
amount of capacitive load. Driving up to 500 pF does not cause
any instability in the amplifier. However, overshoot in the
frequency response increases slightly.
“Hot” plugging the input to a signal generally does not present a
problem for the SSM2135, assuming the signal does not have
any voltage exceeding the device’s supply voltage. If so, it is
advisable to add a series input resistor to limit the current, as
well as a Zener diode to clamp the input to a voltage no higher
than the supply.
The SSM2135 makes an excellent output amplifier for +5 V
only audio systems such as a multimedia workstation, a CD
output amplifier, or an audio mixing system. The amplifier has
large output swing even at this supply voltage because it is
designed to swing to the negative rail. In addition, it easily
drives load impedances as low as 25 Ω with low distortion.
REV. D
400
–7–
SSM2135
APPLICATION CIRCUITS
A Low Noise Microphone Preamplifier
A Low Noise Stereo Headphone Driver Amplifier
Figure 29 shows the SSM2135 used in a stereo headphone
driver for multimedia applications with the AD1848, a 16-bit
stereo codec. The SSM2135 is equally well suited for the serialbused AD1849 stereo codec. The headphone’s impedance can
be as low as 25 Ω, which covers most commercially available high
fidelity headphones. Although the amplifier can operate at up to
± 18 V supply, it is just as efficient powered by a single +5 V. At
this voltage, the amplifier has sufficient output drive to deliver
distortion-free sound to a low impedance headphone.
The SSM2135’s 4.7 nV/√Hz input noise in conjunction with
low distortion makes it an ideal device for amplifying low level
signals such as those produced by microphones. Figure 31 illustrates a stereo microphone input circuit feeding a multimedia
sound codec. As shown, the gain is set at 100 (40 dB), although
it can be set to other gains depending on the microphone output
levels. Figure 32 shows the preamplifier’s harmonic distortion
performance with 1 V rms output while operating from a single
+5 V supply.
LOUT
VCC
GND
VREF
10kΩ
40
35/36
34/37
8.66kΩ
2
+5V
3
1/2
SSM2135
10µF
32
0.1µF
10µF
5
AD1848
ROUT
470µF
1
0.1µF
6
41
10kΩ
8
L CH
The SSM2135 is biased to 2.25 V by the VREF pin of the
AD1848 codec. The same voltage is buffered by the 2N4124
transistor to provide “phantom power” to the microphone. A
typical electret condenser microphone with an impedance range
of 100 Ω to 1 kΩ works well with the circuit. This power booster
circuit may be omitted for dynamic microphone elements.
10kΩ
R CH
0.1µF
7
+5V
AGND
100Ω
L CHANNEL
MIC IN
1/2
470µF
4 SSM2135
2
2kΩ
29
1
10µF
3
8.66kΩ
10µF
8
10kΩ
1/2
4 SSM2135
+5V
0.1µF
+5V
2N4124
Figure 29. A Stereo Headphone Driver for Multimedia
Sound Codec
Figure 30 shows the total harmonic distortion characteristics
versus frequency driving into a 32 Ω load, which is a very typical
impedance for a high quality stereo headphone. The SSM2135
has excellent power supply rejection, and as a result, is tolerant
of poorly regulated supplies. However, for best sonic quality, the
power supply should be well regulated and heavily bypassed to
minimize supply modulation under heavy loads. A minimum of
10 µF bypass is recommended.
Figure 30. Headphone Driver THD+N vs. Frequency into a
32 Ω Load (VS = +5 V, with 80 kHz Low-Pass Filter)
R CHANNEL
MIC IN
34/37
32
10µF
2kΩ
35/36
0.1µF
LMIC
VCC
GND
VREF
AD1848
10kΩ
5
7
10µF
6
100Ω
1/2
SSM2135
28
RMIC
10kΩ
Figure 31. Low Noise Microphone Preamp for Multimedia
Sound Codec
Figure 32. MIC Preamp THD+N Performance (VS = +5 V,
AV = 40 dB, VOUT = 1 V rms, with 80 kHz Low-Pass Filter)
–8–
REV. D
SSM2135
An 18-Bit Stereo CD-DAC Output Amplifier
A Single Supply Differential Line Receiver
The SSM2135 makes an ideal single supply stereo output
amplifier for audio D/A converters because of its low noise and
distortion. Figure 33 shows the implementation of an 18-bit stereo DAC channel. The output amplifier also provides low-pass
filtering for smoothing the oversampled audio signal. The filter’s
cutoff frequency is set at 22.5 kHz and it has a maximally flat
response from dc to 20 kHz.
Receiving a differential signal with minimum distortion is
achieved using the circuit in Figure 35. Unlike a difference
amplifier (a subtractor), the circuit has a true balanced input
impedance regardless of input drive levels. That is, each input
always presents a 20 kΩ impedance to the source. For best
common-mode rejection performance, all resistors around the
differential amplifier must be very well matched. Best results
can be achieved using a 10 kΩ precision resistor network.
As mentioned above, the amplifier’s outputs can drive directly
into a stereo headphone that has impedance as low as 25 Ω with
no additional buffering required.
10kΩ
+5V
10µF+0.1µF
+5V SUPPLY
1
2
3
4
5
6
VL
18-BIT
DAC
VBL
LL
DL
7.68kΩ
VOL
CK
VREF
DR
LR
AD1868
18-BIT
SERIAL
REG.
VREF
8
2
4
220µF
1
LEFT
CHANNEL
OUTPUT
DIFFERENTIAL
AUDIO IN
1/2
4 SSM2135
20kΩ
7.68kΩ
12
2.0V
1µF
100pF
9.76kΩ
220µF
6
9
7
330pF
5
10Ω
7
5
100Ω
RIGHT
CHANNEL
OUTPUT
10µF
1
+5V
8
3
2
4
0.1µF
47kΩ
1/2
SSM2135
AUDIO
OUT
1/2
SSM2135
7.68kΩ
7.68kΩ
VS
20kΩ
6
100pF
10
18-BIT
DAC
10kΩ
47kΩ
11
DGND
VBR
8
330pF
VOR
7
8
1
3
9.76kΩ
14
13
AGND
2
3
15
18-BIT
SERIAL
REG.
20kΩ
1/2
SSM2135
16
7.5kΩ
+5V
5kΩ
1/2
SSM2135
2.5kΩ
Figure 33. +5 V Stereo 18-Bit DAC
Figure 35. Single Supply Balanced Differential Line
Receiver
A Single Supply Differential Line Driver
Signal distribution and routing is often required in audio
systems, particularly portable digital audio equipment for
professional applications. Figure 34 shows a single supply line
driver circuit that has differential output. The bottom amplifier
provides a 2 V dc bias for the differential amplifier in order to
maximize the output swing range. The amplifier can output a
maximum of 0.8 V rms signal with a +5 V supply. It is capable
of driving into 600 Ω line termination at a reduced output
amplitude.
A Pseudo-Reference Voltage Generator
For single supply circuits, a reference voltage source is often
required for biasing purposes or signal offsetting purposes. The
circuit in Figure 36 provides a supply splitter function with low
output impedance. The 1 µF output capacitor serves as a charge
reservoir to handle a sudden surge in demand by the load as
well as providing a low ac impedance to it. The 0.1 µF feedback
capacitor compensates the amplifier in the presence of a heavy
capacitive load, maintaining stability.
1kΩ
The output can source or sink up to 12 mA of current with
+5 V supply, limited only by the 100 Ω output resistor. Reducing the resistance will increase the output current capability.
Alternatively, increasing the supply voltage to 12 V also
improves the output drive to more than 25 mA.
+5V
10µF+0.1µF
2
8
1
100µF
3
AUDIO
IN
4
1kΩ
1/2
SSM2135
DIFFERENTIAL
AUDIO OUT
1kΩ
VS+ = +5V → +12V
R3
2.5kΩ
6
7
10kΩ
5
2.0V
C1
0.1µF
1/2
SSM2135
2.5kΩ
+5V
0.1µF
100Ω
1µF
8
2
7.5kΩ
3
4
3
4
R4
100Ω
+
VS
1
C2
1µF
2
OUTPUT
R2
5kΩ
5kΩ
Figure 36. Pseudo-Reference Generator
Figure 34. Single Supply Differential Line Driver
REV. D
8
1/2
SSM2135
2
1
1/2
SSM2135
R1
5kΩ
+5V
–9–
SSM2135
A Digital Volume Control Circuit
A Logarithmic Volume Control Circuit
Working in conjunction with the AD7528/PM7528 dual 8-bit
D/A converter, the SSM2135 makes for an efficient audio
attenuator, as shown in Figure 37. The circuit works off a single
+5 V supply. The DAC’s are biased to a 2 V reference level
which is sufficient to keep the DAC’s internal R-2R ladder
switches operating properly. This voltage is also the optimal
midpoint of the SSM2135’s common-mode and output swing
range. With the circuit as shown, the maximum input and
output swing is 1.25 V rms. Total harmonic distortion measures
a respectable 0.01% at 1 kHz and 0.1% at 20 kHz. The frequency response at any attenuation level is flat to 20 kHz.
Figure 38 shows a logarithmic version of the volume control
function. Similar biasing is used. With an 8-bit bus, the
AD7111 provides an 88.5 dB attenuation range. Each bit
resolves a 0.375 dB attenuation. Refer to AD7111 data sheet for
attenuation levels for each input code.
+5V
0.1µF
3
47µF
L AUDIO
IN
Each DAC can be controlled independently via the 8-bit parallel
data bus. The attenuation level is linearly controlled by the
binary weighting of the digital data input. Total attenuation
ranges from 0 dB to 48 dB.
10
+5V
10µF+0.1µF
L AUDIO
IN
4
REF A
47µF
FB
OUTA
2
2
8
3
AD7111
16
1
FB
OUTA
AGND
8
R AUDIO
IN
3
14
16
47µF
1
15 DGND VDD FB
OUTA
VIN
AD7111 AGND
2
10
10
6
1/2
SSM2135
7
1µF
47µF
R AUDIO
OUT
5
2kΩ
+5V
0.1µF
2.0V
4 SSM2135
L AUDIO
OUT
1/2
4 SSM2135
100Ω
L AUDIO
OUT
47µF
1
2
DATA IN &
CONTROL
1/2
2
3
47µF
1
DAC A
VDD
+5V
0.1µF
3
AD/PM-7528
14
15 DGND
VIN
+5V
10µF+0.1µF
+5V
1
8
2
7.5kΩ
3
4
1/2
SSM2135
5kΩ
DATA IN
6
CONTROL
SIGNAL
R AUDIO
IN
15
16
DACA/
DACB
CS
19
Figure 38. Single Supply Logarithmic Volume Control
WR
18
REF B
47µF
FB
OUTB
DAC B
VDD
17
20
6
1
5
1/2
SSM2135
7
R AUDIO
OUT
2kΩ
DGND
0.1µF
+5V
0.1µF
5
100Ω
+5V
47µF
2.0V
1µF
+5V
1
8
2
7.5kΩ
3 2.0V
4
1/2
SSM2135
5kΩ
Figure 37. Digital Volume Control
–10–
REV. D
SSM2135
SPICE MACROMODEL
*SSM2135 SPICE Macro-Model
9/92, Rev. A
*
JCB/ADI
*Copyright 1993 by Analog Devices, Inc.
*
*Node Assignments
*
*
Noninverting Input
*
Inverting Input
*
Positive Supply
*
Negative Supply
*
Output
.SUBCKT SSM2135
3
2
7
4
6
*
* INPUT STAGE
R3
4
19 1.5E3
R4
4
20 1.5E3
C1
19 20 5.311E–12
I1
7
18 106E–6
IOS
2
3
25E–09
EOS 12 5
POLY(1) 51 4
25E–06 1
Q1
19 3
18
PNP1
Q2
20 12 18
PNP1
CIN 3
2
3E–12
D1
3
1
DY
D2
2
1
DY
EN
5
2
22
0
1
GN1 0
2
25
0
1E–5
GN2 0
3
28
0
1E–5
*
* VOLTAGE NOISE SOURCE WITH FLICKER NOISE
DN1 21 22 DEN
DN2 22 23 DEN
VN1 21 0
DC 2
VN2 0
23 DC 2
*
* CURRENT NOISE SOURCE WITH FLICKER NOISE
DN3 24 25 DIN
DN4 25 26 DIN
VN3 24 0
DC 2
VN4 0
26 DC 2
*
* SECOND CURRENT NOISE SOURCE
DN5 27 28 DIN
DN6 28 29 DIN
VN5 27 0
DC 2
VN6 0
29 DC 2
*
* GAIN STAGE & DOMINANT POLE AT .2000E+01 HZ
G2
34 36 19
20 2.65E–04
R7
34 36 39E+06
V3
35 4
DC
6
D4
36 35 DX
VB2 34 4
1.6
*
* SUPPLY/2 GENERATOR
ISY
7
4
0.2E–3
R10 7
60 40E+3
R11 60 4
40E+3
C3
60 0
1E–9
*
REV. D
* CMRR STAGE & POLE AT 6 kHZ
ECM
50 4
POLY(2) 3 60 2 60 0 1.6 1.6
CCM 50 51 26.5E–12
RCM1 50 51 1E6
RCM2 51 4
1
*
*
OUTPUT STAGE
R12 37 36 1E3
R13 38 36 500
C4 37 6 20E–12
C5 38 39 20E–12
M1 39 36 4 4 MN L=9E–6 W=1000E–6 AD=15E–9 AS=15E–9
M2 45 36 4 4 MN L=9E–6 W=1000E–6 AD=15E–9 AS=15E–9
5
39 47 DX
D6 47 45 DX
Q3 39 40 41 QPA 8
VB 7 40 DC 0.861
R14 7 41 375
Q4 41 7 43 QNA 1
R17 7 43 15
Q5 43 39 6
QNA 20
Q6 46 45 6
QPA 20
R18 46 4 15
Q7 36 46 4
QNA 1
M3 6 36 4 4 MN L=9E–6 W=2000E–6 AD=30E–9 AS=30E–9
*
* NONLINEAR MODELS USED
*
.MODEL DX D (IS=1E–15)
.MODEL DY D (IS=1E–15 BV=7)
.MODEL PNP1 PNP (BF=220)
.MODEL DEN D(IS=1E–12 RS=1016 KF=3.278E–15 AF=1)
.MODEL DIN D(IS=1E–12 RS=100019 KF=4.173E–15 AF=1)
.MODEL QNA NPN(IS=1.19E–16 BF=253 VAF=193 VAR=15 RB=2.0E3
+ IRB=7.73E–6 RBM=132.8 RE=4 RC=209 CJE=2.1E–13 VJE=0.573
+ MJE =0.364 CJC=1.64E–13 VJC=0.534 MJC=0.5 CJS=1.37E–12
+ VJS=0.59 MJS=0.5 TF=0.43E–9 PTF=30)
.MODEL QPA PNP(IS=5.21E–17 BF=131 VAF=62 VAR=15 RB=1.52E3
+ IRB=1.67E 5–RBM=368.5 RE=6.31 RC=354.4 CJE=1.1E–13
+ VJE=0.745 MJE=0.33 CJC=2.37E–13 VJC=0.762 MJC=0.4
+ CJS=7.11E–13 VJS=0.45 MJS=0.412 TF=1.0E–9 PTF=30)
.MODEL MN NMOS(LEVEL=3 VTO=1.3 RS=0.3 RD=0.3 TOX=8.5E–8
+ LD=1.48E–6WD=1E–6 NSUB=1.53E16UO=650 DELTA= 10VMAX=2E5
+ XJ=1.75E–6 KAPPA=0.8 ETA=0.066 THETA=0.01TPG=1 CJ=2.9E–4
+ PB=0.837 MJ=0.407 CJSW=0.5E–9 MJSW=0.33)
*
.ENDS SSM-2135
–11–
SSM2135
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
8
C1772a–10–10/97
8-Lead Plastic DIP (N-8)
5
0.280 (7.11)
0.240 (6.10)
1
4
0.070 (1.77)
0.045 (1.15)
0.430 (10.92)
0.348 (8.84)
0.325 (8.25)
0.300 (7.62)
0.015
(0.381) TYP
0.210
(5.33)
MAX
0.195 (4.95)
0.115 (2.93)
0.130
(3.30)
MIN
0.160 (4.06)
0.115 (2.93)
0.100
(2.54)
BSC
0.022 (0.558)
0.014 (0.356)
SEATING
PLANE
0.015 (0.381)
0.008 (0.204)
0°- 15°
8-Lead Narrow-Body (SO-8)
8
5
0.2440 (6.20)
0.2284 (5.80)
0.1574 (4.00)
0.1497 (3.80)
4
1
0.1968 (5.00)
0.1890 (4.80)
0.0098 (0.25)
0.0040 (0.10)
0.0688 (1.75)
0.0532 (1.35)
0.0196 (0.50)
× 45°
0.0099 (0.25)
0°- 8°
0.0500 (1.27)
0.0160 (0.41)
PRINTED IN U.S.A.
0.0500 (1.27) BSC 0.0192 (0.49) SEATING
0.0138 (0.35) PLANE
0.0098 (0.25)
0.0075 (0.19)
–12–
REV. D
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