Texas Instruments | THS1209: 12-Bit, 2 Analog Input, 8 MSPS, Simultaneous Sampling A/D Converte (Rev. B) | Datasheet | Texas Instruments THS1209: 12-Bit, 2 Analog Input, 8 MSPS, Simultaneous Sampling A/D Converte (Rev. B) Datasheet

Texas Instruments THS1209: 12-Bit, 2 Analog Input, 8 MSPS, Simultaneous Sampling A/D Converte (Rev. B) Datasheet
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
FEATURES
D Simultaneous Sampling of 2 Single-Ended
Signals or 1 Differential Signal
D
D
D
D
D
D
D
D
D
Signal-to-Noise Ratio: 68 dB at fI = 2 MHz
Differential Nonlinearity Error: ±1 LSB
Integral Nonlinearity Error: ±1.5 LSB
Auto-Scan Mode for 2 Inputs
3-V or 5-V Digital Interface Compatible
THS1209 consists of two analog inputs, which are
sampled simultaneously. These inputs can be selected
individually and configured to single-ended or
differential inputs. Internal reference voltages for the
ADC (1.5 V and 3.5 V) are provided. An external
reference can also be chosen to suit the dc accuracy
and temperature drift requirements of the application.
The THS1209C is characterized for operation from 0°C
to 70°C, and the THS1209I is characterized for
operation from –40°C to 85°C.
Low Power: 218 mW Max at 5 V
DA PACKAGE
(TOP VIEW)
Power Down: 1 mW Max
5-V Analog Single Supply Operation
Internal Voltage References . . . 50 PPM/°C
and ±5% Accuracy
D Glueless DSP Interface
D Parallel µC/DSP Interface
APPLICATIONS
D Radar Applications
D Communications
D Control Applications
D High-Speed DSP Front-End
D Automotive Applications
DESCRIPTION
The THS1209 is a CMOS, low-power, 12-bit, 8 MSPS
analog-to-digital converter (ADC). The speed,
resolution, bandwidth, and single-supply operation are
suited for applications in radar, imaging, high-speed
acquisition, and communications. A multistage
pipelined architecture with output error correction logic
provides for no missing codes over the full operating
temperature range. Internal control registers allow for
programming the ADC into the desired mode. The
D0
D1
D2
D3
D4
D5
BVDD
BGND
D6
D7
D8
D9
RA0
RA1
CONV_CLK
SYNC
1
32
2
31
3
30
4
29
5
28
6
27
7
26
8
25
9
24
10
23
11
22
12
21
13
20
14
19
15
18
16
17
NC
RESET
AINP
AINM
REFIN
REFOUT
REFP
REFM
AGND
AVDD
CS0
CS1
WR (R/W)
RD
DVDD
DGND
ORDERING INFORMATION
PACKAGED DEVICE
TA
TSSOP
(A)
0°C to 70°C
THS1209CDA
–40°C to 85°C
THS1209IDA
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
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Copyright  2002, Texas Instruments Incorporated
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during
storage or handling to prevent electrostatic damage to the MOS gates.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range unless otherwise noted(1)
UNITS
Supply
Su
ly voltage range
DGND to DVDD
–0.3 V to 8.5 V
BGND to BVDD
–0.3 V to 8.5 V
AGND to AVDD
–0.3 V to 8.5 V
Analog input voltage range
AGND –0.3 V to AVDD + 1.5 V
–0.3 V + AGND to AVDD + 0.3 V
Reference input voltage
Digital input voltage range
–0.3 V to BVDD/DVDD + 0.3 V
Operating virtual junction temperature range, TJ
–40°C to 150°C
THS1209C
Operating free-air
free air temperature range,
range TA
0°C to 70°C
THS1209I
–40°C to 85°C
Storage temperature range, Tstg
–65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds
260°C
(1) Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
RECOMMENDED OPERATING CONDITIONS
POWER SUPPLY
Supply
y voltage
g
MIN
NOM
MAX
AVDD
DVDD
4.75
5
5.25
4.75
5
5.25
BVDD
3
ANALOG AND REFERENCE INPUTS
Analog input voltage in single-ended configuration
Common-mode input voltage VCM in differential configuration
NOM
MAX
VREFM
1
VREFP
4
V
2.5
3.5
AVDD–1.2
V
1.4
Input voltage difference, REFP – REFM
DIGITAL INPUTS
MIN
High level input voltage,
High-level
voltage VIH
BVDD = 3.3 V
BVDD = 5.25 V
Low level input voltage,
Low-level
voltage VIL
BVDD = 3.3 V
BVDD = 5.25 V
Input CONV_CLK frequency
CONV_CLK pulse duration, clock high, tw(CONV_CLKH)
CONV_CLK pulse duration, clock low, tw(CONV_CLKL)
Operating free-air
free air temperature,
temperature TA
2
V
5.25
MIN
External reference voltage,VREFP (optional)
External reference voltage, VREFM (optional)
UNIT
UNIT
V
1.5
V
2
V
NOM
MAX
UNIT
2
V
2.8
V
0.8
0.8
V
DVDD = 4.75 V to 5.25 V
DVDD = 4.75 V to 5.25 V
0.1
62
62
5000
ns
DVDD = 4.75 V to 5.25 V
THS1209CDA
62
62
5000
ns
THS1209IDA
8
V
0
70
–40
85
MHz
°C
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
ELECTRICAL CHARACTERISTICS
over recommended operating conditions, AVDD = DVDD = 5 V, BVDD = 3.3 V, VREF = internal (unless otherwise noted)
DIGITAL SPECIFICATIONS
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Digital inputs
IIH
IIL
High-level input current
Low-level input current
DVDD = digital inputs
Digital input = 0 V
–50
50
µA
–50
50
µA
Ci
Input capacitance
Digital outputs
5
VOH
VOL
High-level output voltage
Low-level output voltage
IOH = –50 µA,
IOL = 50 µA,
BVDD = 3.3 V, 5 V
BVDD = 3.3 V, 5 V
IOZ
CO
High-impedance-state output current
CS1 = DGND,
CS0 = DVDD
CL
Load capacitance at databus D0 – D9
pF
BVDD–0.5
V
–10
Output capacitance
0.4
V
10
µA
5
pF
30
pF
ELECTRICAL CHARACTERISTICS
over recommended operating conditions, AVDD = DVDD = 5 V, BVDD = 3.3 V, fs = 8 MSPS, VREF = internal (unless otherwise noted)
DC SPECIFICATIONS
PARAMETER
TEST CONDITIONS
Resolution
MIN
TYP
MAX
12
UNIT
Bits
Accuracy
Integral nonlinearity, INL
Differential nonlinearity, DNL
After calibration in single-ended mode
Offset error
After calibration in differential mode
Gain error
±1.5
LSB
±1
LSB
20
LSB
–20
20
LSB
–20
20
LSB
Analog input
Input capacitance
Input leakage current
15
VAIN = VREFM to VREFP
pF
±10
µA
V
Internal voltage reference
Accuracy, VREFP
3.3
3.5
3.7
Accuracy, VREFM
1.4
1.5
1.6
Temperature coefficient
50
Reference noise
µV
100
Accuracy, REFOUT
2.475
V
PPM/°C
2.5
2.525
V
Power supply
IDDA
IDDD
Analog supply current
AVDD = DVDD = 5 V, BVDD =3.3 V
AVDD = DVDD = 5 V, BVDD = 3.3 V
38
40
mA
0.5
1
mA
IDDB
Buffer supply current
AVDD = DVDD = 5 V, BVDD = 3.3 V
AVDD = DVDD = 5 V, BVDD = 3.3 V
1.5
4
mA
Power dissipation
188
218
mW
Power dissipation in power down with conversion
clock inactive
AVDD = DVDD = 5 V, BVDD = 3.3 V
0.25
Digital supply current
mW
3
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
ELECTRICAL CHARACTERISTICS
over recommended operating conditions, VREF = internal, fs = 8 MSPS, fI = 2 MHz at –1 dBFS (unless otherwise noted)
AC SPECIFICATIONS, AVDD = DVDD = 5 V, BVDD = 3.3 V, CL < 30 pF
PARAMETER
SINAD
SNR
THD
ENOB
(SNR)
SFDR
Signal to noise ratio + distortion
Signal-to-noise
Signal to noise ratio
Signal-to-noise
Total harmonic distortion
MIN
TYP
Differential mode
TEST CONDITIONS
63
65
dB
Single-ended mode
62
64
dB
Differential mode
64
69
dB
Single-ended mode
64
68
Spurious free dynamic range
UNIT
dB
Differential mode
–70
–67
Single-ended mode
–68
–64
Differential mode
Effective number of bits
MAX
dB
dB
10.17
10.5
Bits
Single-ended mode
10
10.3
Bits
Differential mode
67
71
dB
Single-ended mode
65
69
dB
Analog Input
Full-power bandwidth with a source impedance of 150 Ω in
differential configuration.
Full scale sinewave, –3 dB
98
MHz
Full-power bandwidth with a source impedance of 150 Ω in
single-ended configuration.
Full scale sinewave, –3 dB
54
MHz
Small-signal bandwidth with a source impedance of 150 Ω in
differential configuration.
100 mVpp sinewave, –3 dB
98
MHz
Small-signal bandwidth with a source impedance of 150 Ω in
single-ended configuration.
100 mVpp sinewave, –3 dB
54
MHz
TIMING REQUIREMENTS
AVDD = DVDD = 5 V, BVDD = 3.3 V, VREF = internal, CL < 30 pF
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
CONV
CLK
tpipe
Latency
tsu(CONV_CLKL-READL)
tsu(READH-CONV_CLKL)
Setup time, CONV_CLK low before CS valid
10
Setup time, CS invalid to CONV_CLK low
20
td(CONV_CLKL-SYNCL)
td(CONV_CLKL-SYNCH)
Delay time, CONV_CLK low to SYNC low
10
ns
Delay time, CONV_CLK low to SYNC high
10
ns
4
5
ns
ns
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
Terminal Functions
TERMINAL
I/O
DESCRIPTION
NAME
NO.
AINP
30
I
Analog input, single-ended or positive input of differential channel A
AINM
29
I
Analog input, single-ended or negative input of differential channel A
AVDD
23
I
Analog supply voltage
AGND
24
I
Analog ground
BVDD
7
I
Digital supply voltage for buffer
BGND
8
I
Digital ground for buffer
CONV_CLK
15
I
Digital input. This input is the conversion clock input
CS0
22
I
Chip select input (active low)
CS1
21
I
Chip select input (active high)
SYNC
16
O
Synchronization output. This signal indicates in a multi-channel operation that data of channel A is brought to the
digital output and can therefore be used for synchronization.
DGND
17
I
Digital ground. Ground reference for digital circuitry.
DVDD
18
I
Digital supply voltage
D0 – D9
1–6,
9–12
I/O/Z
Digital input, output; D0 = LSB
RA0/D10
13
I/O/Z
Digital input, output. The data line D10 is also used as an address line (RA0) for the control register. This is
required for writing to control register 0 and control register 1. See Table 7.
RA1/D11
14
I/O/Z
Digital input, output (D11 = MSB). The data line D11 is also used as an address line (RA1) for the control register.
This is required for writing to control register 0 and control register 1. See Table 7.
NC
32
O
Not connected
REFIN
28
I
Common-mode reference input for the analog input channels. It is recommended that this pin be connected to the
reference output REFOUT.
REFP
26
I
Reference input, requires a bypass capacitor of 10 µF to AGND in order to bypass the internal reference voltage.
An external reference voltage at this input can be applied. This option can be programmed through control
register 0. See Table 8.
REFM
25
I
Reference input, requires a bypass capacitor of 10 µF to AGND in order to bypass the internal reference voltage.
An external reference voltage at this input can be applied. This option can be programmed through control
register 0. See Table 8.
RESET
31
I
Hardware reset of the THS1209. Sets the control register to default values.
REFOUT
27
O
Analog fixed reference output voltage of 2.5 V. Sink and source capability of 250 µA. The reference output
requires a capacitor of 10 µF to AGND for filtering and stability.
RD(1)
19
I
The RD input is used only if the WR input is configured as a write only input. In this case, it is a digital input, active
low as a data read select from the processor. See timing section.
WR (R/W)(1)
20
I
This input is programmable. It functions as a read-write input (R/W) and can also be configured as a write-only
input (WR), which is active low and used as data write select from the processor. In this case, the RD input is used
as a read input from the processor. See timing section.
(1) The start-conditions of RD and WR (R/W) are unknown. The first access to the ADC has to be a write access to initialize the ADC.
5
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
FUNCTIONAL BLOCK DIAGRAM
AVDD
DVDD
3.5 V
REFP
1.5 V
2.5 V
1.225 V
REF
REFOUT
REFM
REFP
REFIN
S/H
AINP
AINM
Single-Ended
and/or
Differential
MUX
+
–
REFM
BVDD
12-Bit
Pipeline
ADC
12
S/H
Buffers
CONV_CLK
CS0
CS1
RD
Logic
and
Control
Control
Register
BGND
WR (R/W)
SYNC
RESET
AGND
6
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10/RA0
D11/RA1
DGND
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
TYPICAL CHARACTERISTICS
TOTAL HARMONIC DISTORTION
vs
SAMPLING FREQUENCY (SINGLE-ENDED)
SIGNAL-TO-NOISE AND DISTORTION
vs
SAMPLING FREQUENCY (SINGLE-ENDED)
80
SINAD – Signal-to-Noise and Distortion – dB
70
THD – Total Harmonic Distortion – dB
75
70
65
60
55
50
AVDD = 5 V, DVDD = BVDD = 3 V,
fIN = 500 kHz, AIN = –1 dBFS
45
40
65
60
55
50
AVDD = 5 V, DVDD = BVDD = 3 V,
fIN = 500 kHz, AIN = –1 dBFS
45
40
0
1
2
3
4
5
6
7
8
9
0
1
fs – Sampling Frequency – MHz
2
Figure 1
4
5
6
7
8
9
Figure 2
SIGNAL-TO-NOISE
vs
SAMPLING FREQUENCY (SINGLE-ENDED)
SPURIOUS FREE DYNAMIC RANGE
vs
SAMPLING FREQUENCY (SINGLE-ENDED)
70
90
85
65
80
SNR – Signal-to-Noise – dB
SFDR – Spurious Free Dynamic Range – dB
3
fs – Sampling Frequency – MHz
75
70
65
60
55
50
60
55
50
AVDD = 5 V, DVDD = BVDD = 3 V,
fIN = 500 kHz, AIN = –1 dBFS
45
AVDD = 5 V, DVDD = BVDD = 3 V,
fIN = 500 kHz, AIN = –1 dBFS
45
40
40
0
1
2
3
4
5
6
7
fs – Sampling Frequency – MHz
Figure 3
8
9
0
1
2
3
4
5
6
7
8
9
fs – Sampling Frequency – MHz
Figure 4
7
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
TYPICAL CHARACTERISTICS
TOTAL HARMONIC DISTORTION
vs
SAMPLING FREQUENCY (DIFFERENTIAL)
SIGNAL-TO-NOISE AND DISTORTION
vs
SAMPLING FREQUENCY (DIFFERENTIAL)
85
SINAD – Signal-to-Noise and Distortion – dB
80
THD – Total Harmonic Distortion – dB
80
75
70
65
60
55
50
AVDD = 5 V, DVDD = BVDD = 3 V,
fIN = 500 kHz, AIN = –1 dBFS
45
40
75
70
65
60
55
50
AVDD = 5 V, DVDD = BVDD = 3 V,
fIN = 500 kHz, AIN = –1 dBFS
45
40
0
1
2
3
4
5
6
7
8
9
0
1
fs – Sampling Frequency – MHz
2
Figure 5
5
6
7
8
9
SIGNAL-TO-NOISE
vs
SAMPLING FREQUENCY (DIFFERENTIAL)
80
100
95
75
90
SNR – Signal-to-Noise – dB
SFDR – Spurious Free Dynamic Range – dB
4
Figure 6
SPURIOUS FREE DYNAMIC RANGE
vs
SAMPLING FREQUENCY (DIFFERENTIAL)
85
80
75
70
65
60
55
AVDD = 5 V, DVDD = BVDD = 3 V,
fIN = 500 kHz, AIN = –1 dBFS
50
70
65
60
55
50
AVDD = 5 V, DVDD = BVDD = 3 V,
fIN = 500 kHz, AIN = –1 dBFS
45
45
40
40
0
1
2
3
4
5
6
7
fs – Sampling Frequency – MHz
Figure 7
8
3
fs – Sampling Frequency – MHz
8
9
0
1
2
3
4
5
6
7
fs – Sampling Frequency – MHz
Figure 8
8
9
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
TYPICAL CHARACTERISTICS
TOTAL HARMONIC DISTORTION
vs
INPUT FREQUENCY (SINGLE-ENDED)
SIGNAL-TO-NOISE AND DISTORTION
vs
INPUT FREQUENCY (SINGLE-ENDED)
80
75
SINAD – Signal-to-Noise and Distortion – dB
THD – Total Harmonic Distortion – dB
80
70
65
60
55
50
45
40
0.0
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
0.5
1.0
1.5
2.0
2.5
3.0
3.5
75
70
65
60
55
50
45
40
0.0
4.0
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
0.5
fi – Input Frequency – MHz
2.0
2.5
3.0
3.5
4.0
Figure 10
SIGNAL-TO-NOISE
vs
INPUT FREQUENCY (SINGLE-ENDED)
SPURIOUS FREE DYNAMIC RANGE
vs
INPUT FREQUENCY (SINGLE-ENDED)
80
100
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
75
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
90
SNR – Signal-to-Noise – dB
SFDR – Spurious Free Dynamic Range – dB
1.5
fi – Input Frequency – MHz
Figure 9
95
1.0
85
80
75
70
65
60
55
50
70
65
60
55
50
45
45
40
0.0
0.5
1.0
1.5
2.0
2.5
3.0
fi – Input Frequency – MHz
Figure 11
3.5
4.0
40
0.0
0.5
1.0
1.5
2.0
2.5
3.0
fi – Input Frequency – MHz
3.5
4.0
Figure 12
9
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
TYPICAL CHARACTERISTICS
SIGNAL-TO-NOISE AND DISTORTION
vs
INPUT FREQUENCY (DIFFERENTIAL)
TOTAL HARMONIC DISTORTION
vs
INPUT FREQUENCY (DIFFERENTIAL)
80
SINAD – Signal-to-Noise and Distortion – dB
THD – Total Harmonic Distortion – dB
80
75
70
65
60
55
50
45
40
0.0
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
0.5
1.0
1.5
2.0
2.5
3.0
3.5
75
70
65
60
55
50
45
40
0.0
4.0
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
0.5
1.0
fi – Input Frequency – MHz
SPURIOUS FREE DYNAMIC RANGE
vs
INPUT FREQUENCY (DIFFERENTIAL)
2.5
3.0
3.5
4.0
SIGNAL-TO-NOISE
vs
INPUT FREQUENCY (DIFFERENTIAL)
100
80
95
75
90
SNR – Signal-to-Noise – dB
SFDR – Spurious Free Dynamic Range – dB
2.0
Figure 14
Figure 13
85
80
75
70
65
60
55
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
70
65
60
55
50
50
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
45
40
0.0
0.5
1.0
1.5
2.0
2.5
3.0
fi – Input Frequency – MHz
Figure 15
10
1.5
fi – Input Frequency – MHz
3.5
45
4.0
40
0.0
0.5
1.0
1.5
2.0
2.5
3.0
fi – Input Frequency – MHz
Figure 16
3.5
4.0
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
TYPICAL CHARACTERISTICS
EFFECTIVE NUMBER OF BITS
vs
SAMPLING FREQUENCY (SINGLE-ENDED)
EFFECTIVE NUMBER OF BITS
vs
SAMPLING FREQUENCY (DIFFERENTIAL)
12
AVDD = 5 V, DVDD = BVDD = 3 V,
fin = 500 kHz, AIN = –1 dBFS
ENOB – Effective Number of Bits – Bits
ENOB – Effective Number of Bits – Bits
12
11
10
9
8
7
6
11
10
9
8
AVDD = 5 V, DVDD = BVDD = 3 V,
fin = 500 kHz, AIN = –1 dBFS
7
6
0
1
2
3
4
5
6
7
8
9
0
1
2
fs – Sampling Frequency – MHz
4
5
6
7
8
9
Figure 18
Figure 17
EFFECTIVE NUMBER OF BITS
vs
INPUT FREQUENCY (SINGLE-ENDED)
EFFECTIVE NUMBER OF BITS
vs
INPUT FREQUENCY (DIFFERENTIAL)
12
12
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
ENOB – Effective Number of Bits – Bits
ENOB – Effective Number of Bits – Bits
3
fs – Sampling Frequency – MHz
11
10
9
8
7
6
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
11
10
9
8
7
6
0.0
0.5
1.0
1.5
2.0
2.5
3.0
fi – Input Frequency – MHz
Figure 19
3.5
4.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
fi – Input Frequency – MHz
Figure 20
11
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DNL – Differential Nonlinearity – LSB
TYPICAL CHARACTERISTICS
DIFFERENTIAL NONLINEARITY
vs
ADC CODE
1.0
0.8
AVDD = 5 V
DVDD = BVDD = 3 V
fs = 8 MSPS
0.6
0.4
0.2
–0.0
–0.2
–0.4
–0.6
–0.8
–1.0
0
500
1000
1500
2000
2500
3000
3500
4000
3000
3500
4000
ADC Code
Figure 21
INL – Integral Nonlinearity – LSB
INTEGRAL NONLINEARITY
vs
ADC CODE
1.0
0.8
0.6
0.4
0.2
–0.0
–0.2
–0.4
AVDD = 5 V
DVDD = BVDD = 3 V
fs = 8 MSPS
–0.6
–0.8
–1.0
0
500
1000
1500
2000
ADC Code
Figure 22
12
2500
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
TYPICAL CHARACTERISTICS
FAST FOURIER TRANSFORM (4096 POINTS)
(SINGLE-ENDED)
vs
FREQUENCY
0
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
fin = 1.25 MHz
Magnitude – dB
–20
–40
–60
–80
–100
–120
–140
0
1000000
2000000
3000000
4000000
f – Frequency – Hz
Figure 23
FAST FOURIER TRANSFORM (4096 POINTS)
(DIFFERENTIAL)
vs
FREQUENCY
0
AVDD = 5 V, DVDD = BVDD = 3 V,
fs = 8 MSPS, AIN = –1 dBFS
fin = 1.25 MHz
Magnitude – dB
–20
–40
–60
–80
–100
–120
–140
0
1000000
2000000
3000000
4000000
f – Frequency – Hz
Figure 24
13
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
DETAILED DESCRIPTION
Reference Voltage
The THS1209 has a built-in reference, which provides the reference voltages for the ADC. VREFP is set to 3.5 V
and VREFM is set to 1.5 V. An external reference can also be used through two reference input pins, REFP and
REFM, if the reference source is programmed as external. The voltage levels applied to these pins establish the
upper and lower limits of the analog inputs to produce a full-scale and zero-scale reading respectively.
Analog Inputs
The THS1209 consists of two analog inputs, which are sampled simultaneously. These inputs can be selected
individually and configured as single-ended or differential inputs. The desired analog input channel can be
programmed.
Converter
The THS1209 uses a 12-bit pipelined multistaged architecture which achieves a high sample rate with low power
consumption. The THS1209 distributes the conversion over several smaller ADC sub-blocks, refining the conversion
with progressively higher accuracy as the device passes the results from stage to stage. This distributed conversion
requires a small fraction of the number of comparators used in a traditional flash ADC. A sample-and-hold amplifier
(SHA) within each of the stages permits the first stage to operate on a new input sample while the second through
the eighth stages operate on the seven preceding samples.
Conversion
An external clock signal with a duty cycle of 50% has to be applied to the clock input (CONV_CLK). A new conversion
is started with every falling edge of the applied clock signal. The conversion values are available at the output with
a latency of 5 clock cycles.
SYNC
In multichannel mode, the first SYNC signal is delayed by [7+ (# Channels Sampled)] cycles of the CONV_CLK after
a SYNC reset. This is due to the latency of the pipeline architecture of the THS1209.
Sampling Rate
The maximum possible conversion rate per channel is dependent on the selected analog input channels. Table 1
shows the maximum conversion rate for different combinations.
Table 1. Maximum Conversion Rate
NUMBER OF CHANNELS
MAXIMUM CONVERSION
RATE PER CHANNEL
1 single-ended channel
1
8 MSPS
2 single-ended channels
2
4 MSPS
1 differential channel
1
8 MSPS
CHANNEL CONFIGURATION
The maximum conversion rate in the continuous conversion mode per channel, fc, is given by:
fc + 8 MSPS
# channels
14
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
CONVERSION MODE
During conversion, the ADC operates with a free running external clock signal applied to the input CONV_CLK. With
every falling edge of the CONV_CLK signal a new converted value is available to the databus with the corresponding
read signal. The THS1209 offers up to two analog inputs to be selected. It is important to provide the channel
information to the system, this means to know which channel is available to the databus. The signal SYNC is disabled
for the selection of one analog input since this information is not required for one analog input.
Figure 25 shows the timing of the conversion when one analog input channel is selected. The maximum throughput
rate is 8 MSPS in this mode. There is a certain timing relationship required for the read signal with respect to the
conversion clock. This can be seen in Figure 26 and Table 2. A more detailed description of the timing is given in the
section timing and signal description of the THS1209.
Sample N+1
Channel 1
Sample N
Channel 1
Sample N+2
Channel 1
Sample N+3
Channel 1
Sample N+4
Channel 1
Sample N+5
Channel 1
Sample N+6
Channel 1
AIN
td(A)
td(pipe)
tw(CONV_CLKH)
tw(CONV_CLKL)
CONV_CLK
tc
tsu(CONV_CLKL-READL)
tsu(READH-CONV_CLKL)
READ†
Data N–4
Channel 1
Data N–3
Channel 1
Data N–2
Channel 1
Data N–1
Channel 1
Data N
Channel 1
Data N+1
Channel 1
Data N+2
Channel 1
†READ is the logical combination from CS0, CS1 and RD
Figure 25. Conversion Timing in 1-Channel Operation
15
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
Figure 26 shows the conversion timing when two analog input channels are selected. The maximum throughput rate
per channel is 4 MSPS in this mode. The data flow in the bottom of the figure shows the order the converted data
is available to the data bus. The SYNC signal is always active low if data of channel 1 is available to the data bus.
There is a certain timing relationship required for the read signal with respect to the conversion clock. This can be
seen in Figure 26 and with the timing specifications. A more detailed description of the timing is given in the section
timing and signal description of the THS1209.
Sample N+1
Channel 1, 2
Sample N
Channel 1, 2
Sample N+2
Channel 1, 2
AIN
td(A)
Sample N+3
Channel 1, 2
td(pipe)
tw(CONV_CLKH)
tw(CONV_CLKL)
CONV_CLK
tc
tsu(CONV_CLKL-READL)
tsu(READH-CONV_CLKL)
READ†
td(CONV_CLKL-SYNCL)
td(CONV_CLKL-SYNCH)
SYNC
Data N–2
Channel 1
Data N–2
Channel 2
Data N–1
Channel 1
Data N–1
Channel 2
Data N
Channel 1
Data N
Channel 2
†READ is the logical combination from CS0, CS1 and RD
Figure 26. Conversion Timing in 2 Channel Operation
16
Data N+1
Channel 1
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
DIGITAL OUTPUT DATA FORMAT
The digital output data format of the THS1209 can be in either binary format or in twos complement format. The
following tables list the digital outputs for the analog input voltages.
Table 2. Binary Output Format for Single-Ended Configuration
SINGLE-ENDED, BINARY OUTPUT
ANALOG INPUT VOLTAGE
DIGITAL OUTPUT CODE
AIN = VREFP
FFFh
AIN = (VREFP + VREFM)/2
800h
AIN = VREFM
000h
Table 3. Twos Complement Output Format for Single-Ended Configuration
SINGLE-ENDED, TWOS COMPLEMENT
ANALOG INPUT VOLTAGE
DIGITAL OUTPUT CODE
AIN = VREFP
7FFh
AIN = (VREFP + VREFM)/2
000h
AIN = VREFM
800h
Table 4. Binary Output Format for Differential Configuration
DIFFERENTIAL, BINARY OUTPUT
ANALOG INPUT VOLTAGE
DIGITAL OUTPUT CODE
Vin = AINP – AINM
VREF = VREFP – VREFM
Vin = VREF
Vin = 0
FFFh
Vin = –VREF
000h
800h
Table 5. Twos Complement Output Format for Differential Configuration
DIFFERENTIAL, BINARY OUTPUT
ANALOG INPUT VOLTAGE
DIGITAL OUTPUT CODE
Vin = AINP – AINM
VREF = VREFP – VREFM
Vin = VREF
Vin = 0
7FFh
Vin = –VREF
800h
000h
17
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
ADC CONTROL REGISTER
The THS1209 contains two 10-bit wide control registers (CR0, CR1) in order to program the device into the desired
mode. The bit definitions of both control registers are shown in Table 7.
Table 6. Bit Definitions of Control Register CR0 and CR1
REG
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
CR0
TEST1
TEST0
SCAN
DIFF1
DIFF0
CHSEL1
CHSEL0
PD
RES
VREF
CR1
RBACK
OFFSET
BIN/2’s
R/W
RES
RES
RES
RES
SRST
RESET
Writing to Control Register 0 and Control Register 1
The 10-bit wide control register 0 and control register 1 can be programmed by addressing the desired control
register and writing the register value to the ADC. The addressing is performed with the upper data bits D10 and D11,
which function in this case as address lines RA0 and RA1. During this write process, the data bits D0 to D9 contain
the desired control register value. Table 8 shows the addressing of each control register.
Table 7. Control Register Addressing
18
D0 – D9
D10/RA0
D11/RA1
Addressed Control Register
Desired register value
0
0
Control register 0
Desired register value
1
0
Control register 1
Desired register value
0
1
Reserved for future
Desired register value
1
1
Reserved for future
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
INITIALIZATION OF THE THS1209
The initialization of the THS1209 should be done according to the configuration flow shown in Figure 27.
Start
Use Default
Values?
No
Yes
Write 0x401 to
THS1209
(Set Reset Bit in CR1)
Clear RESET By
Writing 0x400 to
CR1
Write 0x401 to
THS1209
(Set Reset Bit in CR1)
Clear RESET By
Writing 0x400 to
CR1
Write the User
Configuration to
CR0
Write the User
Configuration to
CR1 (Must Exclude
RESET)
Continue
Figure 27. THS1209 Configuration Flow
19
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
ADC CONTROL REGISTERS
Control Register 0 (see Table 8)
BIT 11
BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
0
0
TEST1
TEST0
SCAN
DIFF1
DIFF0
CHSEL1
CHSEL0
PD
RES
VREF
Table 8. Control Register 0 Bit Functions
BITS
RESET
VALUE
NAME
0
0
VREF
1
0
RES
2
0
PD
3, 4
0,0
CHSEL0,
CHSEL1
5,6
1,0
DIFF0, DIFF1
7
0
SCAN
Autoscan enable
Bit 7 enables or disables the autoscan function of the ADC. Refer to Table 9.
8,9
0,0
TEST0,
TEST1
Test input enable
Bit 8 and bit 9 control the test function of the ADC. Three different test voltages can be measured. This
feedback allows the check of all hardware connections and the ADC operation.
FUNCTION
Vref select:
Bit 0 = 0 → The internal reference is selected.
Bit 0 = 1 → The external reference voltage is selected.
Reserved
Power down.
Bit 2 = 0 → The ADC is active.
Bit 2 = 1 → Power down
The reading and writing to and from the digital outputs is possible during power down.
Channel select
Bit 3 and bit 4 select the analog input channel of the ADC. Refer to Table 9.
Number of differential channels
Bit 5 and bit 6 contain information about the number of selected differential channels. Refer to Table 9.
Refer to Table 10 for selection of the three different test voltages.
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
ANALOG INPUT CHANNEL SELECTION
The analog input channels of the THS1209 can be selected via bits 3 to 7 of control register 0. One single channel
(single-ended or differential) is selected via bit 3 and bit 4 of control register 0. Bit 5 controls the selection between
single-ended and differential configuration. Bit 6 and bit 7 select the autoscan mode, if more than one input channel
is selected. Table 9 shows the possible selections.
Table 9. Analog Input Channel Configurations
BIT 7
AS
BIT 6
DF1
BIT 5
DF0
BIT 4
CHS1
BIT 3
CHS0
0
0
0
0
0
Analog input AINP (single ended)
0
0
0
0
1
Analog input AINM (single ended)
0
0
0
1
0
Reserved
0
0
0
1
1
Reserved
0
0
1
0
0
Differential channel (AINP–AINM)
0
0
1
0
1
Reserved
1
0
0
0
1
Autoscan two single ended channels: AINP, AINM, AINP, …
1
0
0
1
0
Reserved
1
0
0
1
1
Reserved
1
1
0
0
1
Reserved
1
0
1
0
1
Reserved
1
0
1
1
0
Reserved
0
0
1
1
0
Reserved
0
0
1
1
1
Reserved
1
0
0
0
0
Reserved
1
0
1
0
0
Reserved
1
0
1
1
1
Reserved
1
1
0
0
0
Reserved
1
1
0
1
0
Reserved
1
1
0
1
1
Reserved
1
1
1
0
0
Reserved
1
1
1
0
1
Reserved
1
1
1
1
0
Reserved
1
1
1
1
1
Reserved
DESCRIPTION OF THE SELECTED INPUTS
Test Mode
The test mode of the ADC is selected via bit 8 and bit 9 of control register 0. The different selections are shown in
Table 10.
Table 10. Test Mode
BIT 9
TEST1
BIT 8
TEST0
OUTPUT RESULT
0
0
Normal mode
0
1
1
0
1
1
VREFP
((VREFM)+(VREFP))/2
VREFM
Three different options can be selected. This feature allows support testing of hardware connections between the
ADC and the processor.
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
Control Register 1 (see Table 8)
BIT 11
BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
0
1
RBACK
OFFSET
BIN/2s
R/W
RES
RES
RES
RES
SRST
RESET
Table 11. Control Register 1 Bit Functions
BITS
RESET
VALUE
NAME
0
0
RESET
FUNCTION
Reset
Writing a 1 into this bit resets the device and sets the control register 0 and control register 1 to the reset values.
To bring the device out of reset, a 0 has to be written into this bit.
1
0
SRST
Writing a 1 into this bit resets the sync generator. When running in multichannel mode, this must be set during the
configuration cycle.
2, 3
0,0
RES
Always write 0
4
1
RES
Always write 0
5
1
RES
Always write 0
6
0
R/W
R/W, RD/WR selection
Bit 6 of control register 1 controls the function of the inputs RD and WR. When bit 6 in control register 1 is set to
1, WR becomes a R/W input and RD is disabled. From now on a read is signalled with R/W high and a write with
R/W as a low signal. If bit 6 in control register 1 is set to 0, the input RD becomes a read input and the input WR
becomes a write input.
7
0
BIN/2s
Complement select
If bit 7 of control register 1 is set to 0, the output value of the ADC is in twos complement. If bit 7 of
control register 1 is set to 1, the output value of the ADC is in binary format. Refer to Table 2 through Table 5.
8
0
OFFSET
Offset cancellation mode
Bit 8 = 0 → normal conversion mode
Bit 8 = 1 → offset calibration mode
If a 1 is written into bit 8 of control register 1, the device internally sets the inputs to zero and does a conversion. The conversion result is stored in an offset register and subtracted from all conversions in order to
reduce the offset error.
9
0
RBACK
Debug mode
Bit 9 = 0 → normal conversion mode
Bit 9 = 1 → enable debug mode
When bit 9 of control register 1 is set to 1, debug mode is enabled. In this mode, the contents of control register 0
and control register 1 can be read back. The first read after bit 9 is set to 1 contains the value of control register 0.
The second read after bit 9 is set to 1 contains the value of control register 1. To bring the device back into normal
conversion mode, this bit has to be set back to 0 by writing again to control register 1.
22
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
Timing and Signal Description of the THS1209
The reading from the THS1209 and writing to the THS1209 is performed by using the chip select inputs (CS0, CS1),
the write input WR and the read input RD. The write input is configurable to a combined read/write input (R/W). This
is desired in cases where the connected processor consists of a combined read/write output signal (R/W). The two
chip select inputs can be used to interface easily to a processor.
Reading from the THS1209 takes place by an internal RDint signal, which is generated from the logical combination
of the external signals CS0, CS1 and RD (see Figure 4). This signal is then used to strobe the words out and to enable
the output buffers. The last external signal (either CS0, CS1 or RD) to become valid makes RDint active while the
write input (WR) is inactive. The first of those external signals going to its inactive state then deactivates RDint again.
Writing to the THS1209 takes place by an internal WRint signal, which is generated from the logical combination of
the external signals CS0, CS1 and WR. This signal is then used to strobe the control words into the control registers
0 and 1. The last external signal (either CS0, CS1 or WR) to become valid makes WRint active while the read input
(RD) is inactive. The first of those external signals going to its inactive state then deactivates WRint again.
CS0
RDint
CS1
RD
WRint
WR
Control/Data
Registers
Data Bits
Figure 28. Logical Combination of CS0, CS1, RD, and WR
23
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
Read Timing (using RD, RD-controlled)
Figure 29 shows the read-timing behavior when the WR(R/W) input is programmed as a write-input only. The input
RD acts as the read-input in this configuration. This timing is called RD-controlled because RD is the last external
signal of CS0, CS1, and RD which becomes valid.
CS0
CS1
tsu(CS)
ÓÓÓÓÓ
ÓÓÓÓÓ
th(CS)
ÔÔÔÔ
ÔÔÔÔ
WR
tw(RD)
10%
RD
10%
ta
th
90%
90%
D(0–9)
td(CSDAV)
90%
DATA_AV
Figure 29. Read Timing Diagram Using RD (RD-controlled)
Read Timing Parameter (RD-controlled)
PARAMETER
MIN
TYP
MAX
UNIT
tsu(CS)
ta
Setup time, RD low to last CS valid
0
Access time, last CS valid to data valid
0
td(CSDAV)
th
Delay time, last CS valid to DATA_AV inactive
Hold time, first CS invalid to data invalid
0
th(CS)
tw(RD)
Hold time, RD change to first CS invalid
5
ns
10
ns
24
Pulse duration, RD active
ns
10
12
ns
ns
5
ns
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Write Timing (using WR, WR-controlled)
Figure 30 shows the write-timing behavior when the WR(R/W) input is programmed as a write input WR only. The
input RD acts as the read input in this configuration. This timing is called WR-controlled because WR is the last
external signal of CS0, CS1, and WR which becomes valid.
CS0
CS1
tsu(CS)
th(CS)
tw(WR)
WR
RD
10%
10%
ÓÓÓÓ
ÓÓÓÓ
tsu
ÔÔÔÔ
ÔÔÔÔ
th
90%
90%
D(0–9)
DATA_AV
ÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖ
ÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖ
Figure 30. Write Timing Diagram Using WR (WR-controlled)
Write Timing Parameter Using WR (WR-controlled)
PARAMETER
MIN
TYP
MAX
UNIT
tsu(CS)
tsu
Setup time, CS stable to last WR valid
0
ns
Setup time, data valid to first WR invalid
5
ns
th
th(CS)
Hold time, WR invalid to data invalid
2
ns
5
ns
tw(WR)
Pulse duration, WR active
10
ns
Hold time, WR invalid to CS change
25
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
Read Timing (using R/W, CS0-controlled)
Figure 5 shows the read-timing behavior when the WR(R/W) input is programmed as a combined read-write input
R/W. The RD input has to be tied to high-level in this configuration. This timing is called CS0-controlled because CS0
is the last external signal of CS0, CS1, and R/W which becomes valid. The reading of the data should be done with
a certain timing relative to the conversion clock CONV_CLK, as illustrated in Figure 31.
tsu(CSOH–CONV_CLKL)
tsu(CONV_CLKL–CSOL)
CONV_CLK
10%
10%
90%
tw(CS)
CS0
10%
10%
CS1
R/W
ÓÓÓ
ÓÓÓ
tsu(R/W)
ÔÔÔÔ
ÔÔÔÔ
th(R/W)
90%
90%
RD
ta
th
90%
90%
D(0–11)
Figure 31. Read Timing Diagram Using R/W (CS0-controlled)
Read Timing Parameter (CS0-controlled) (1)
PARAMETER
MIN
TYP
MAX
UNIT
tsu(CONV_CLKL_CSOL)
tsu(CSOH–CONV_CLKL)
Setup time, CONV_CLK low before CS valid
10
ns
Setup time, CS invalid to CONV_CLK low
20
ns
tsu(R/W)
ta
Setup time, R/W high to last CS valid
0
ns
Access time, last CS valid to data valid
0
10
ns
th
th(R/W)
Hold time, first CS invalid to data invalid
0
5
ns
Hold time, first external CS invalid to R/W change
5
ns
10
ns
tw(CS)
(1) CS = CSO
26
Pulse duration, CS active
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Write Timing (using R/W, CS0-controlled)
Figure 32 shows the write-timing behavior when the WR(R/W) input is programmed as a combined read-write input
R/W. The RD input has to be tied to high-level in this configuration. This timing is called CS0-controlled because CS0
is the last external signal of CS0, CS1, and R/W which becomes valid. The writing to the THS1209 can be performed
irrespective of the conversion clock signal CONV_CLK.
tw(CS)
CS0
90%
10%
10%
CS1
R/W
ÔÔÔ
ÔÔÔ
ÔÔÔ
tsu(R/W)
ÓÓÓÓ
ÓÓÓÓ
ÓÓÓÓ
th(R/W)
10%
10%
RD
tsu
th
90%
90%
D(0–11)
Figure 32. Write Timing Diagram Using R/W (CS0-controlled)
Write Timing Parameter (CSO-controlled)
PARAMETER
MIN
TYP
MAX
UNIT
tsu(R/W)
tsu
Setup time, R/W stable to last CS valid
0
ns
Setup time, data valid to first CS invalid
5
ns
th
th(R/W)
Hold time, first CS invalid to data invalid
2
ns
Hold time, first CS invalid to R/W change
5
ns
tw(CS)
Pulse duration, CS active
10
ns
27
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SLAS288B – JULY 2000 – REVISED DECEMBER 2002
ANALOG INPUT CONFIGURATION AND REFERENCE VOLTAGE
The THS1209 features two analog input channels. These can be configured for either single-ended or differential
operation. Figure 33 shows a simplified model, where a single-ended configuration for channel AINP is selected. The
reference voltages for the ADC itself are VREFP and VREFM (either internal or external reference voltage). The analog
input voltage range goes from VREFM to VREFP. This means that VREFM defines the minimum voltage, and VREFP
defines the maximum voltage, which can be applied to the ADC. The internal reference source provides the voltage
VREFM of 1.5 V and the voltage VREFP of 3.5 V. The resulting analog input voltage swing of 2 V can be expressed
by:
V
REFM
v AINP v V
(1)
REFP
VREFP
12-Bit
ADC
AINP
VREFM
Figure 33. Single-Ended Input Stage
A differential operation is desired for many applications due to a better signal-to-noise ratio. Figure 34 shows a
simplified model for the analog inputs AINM and AINP, which are configured for differential operation. The differential
operation mode provides in terms of performance benefits over the single-ended mode and is therefore
recommended for best performance. The THS1209 offers 1 differential analog input and in the single-ended mode
2 analog inputs. If the analog input architecture id differential, common-mode noise and common-mode voltages can
be rejected. Additional details for both modes are given below.
VREFP
AINP
+
Σ
VADC
12-Bit
ADC
–
AINM
VREFM
Figure 34. Differential Input Stage
In comparison to the single-ended configuration it can be seen that the voltage, VADC, which is applied at the input
of the ADC, is the difference between the input AINP and AINM. The voltage VADC can be calculated as follows:
V
ADC
+ ABS(AINP–AINM)
(2)
An advantage to single-ended operation is that the common-mode voltage
V
CM
+ AINM ) AINP
2
(3)
can be rejected in the differential configuration, if the following condition for the analog input voltages is true:
AGND v AINM, AINP v AV
1VvV
CM
DD
v4V
(4)
(5)
SINGLE-ENDED MODE OF OPERATION
The THS1209 can be configured for single-ended operation using dc or ac coupling. In every case, the input of the
THS1209 should be driven from an operational amplifier that does not degrade the ADC performance. Because the
THS1209 operates from a 5-V single supply, it is necessary to level-shift ground-based bipolar signals to comply with
its input requirements. This can be achieved with dc- and ac-coupling.
28
www.ti.com
SLAS288B – JULY 2000 – REVISED DECEMBER 2002
DC COUPLING
An operational amplifier can be configured to shift the signal level according to the analog input voltage range of the
THS1209. The analog input voltage range of the THS1209 goes from 1.5 V to 3.5 V. An op-amp can be used as
shown in Figure 35.
Figure 35 shows an example where the analog input signal in the range from –1 V up to 1 V is shifted by an
operational amplifier to the analog input range of the THS1209 (1.5 V to 3.5 V). The operational amplifier is configured
as an inverting amplifier with a gain of –1. The required dc voltage of 1.25 V at the noninverting input is derived from
the 2.5-V output reference REFOUT of the THS1209 by using a resistor divider. Therefore, the op-amp output voltage
is centered at 2.5 V. The 10 µF tantalum capacitor is required for bypassing REFOUT. REFIN of the THS1209 must
be connected directly to REFOUT in single-ended mode. The use of ratio matched, thin-film resistor networks
minimizes gain and offset errors.
R1
3.5 V
2.5 V
1.5 V
5V
1V
0V
R1
_
THS1209
RS
AINP
–1 V
1.25 V
+
C
REFIN
REFOUT
+
R2
10 µF
R2
Figure 35. Level-Shift for DC-Coupled Input
DIFFERENTIAL MODE OF OPERATION
For the differential mode of operation, a conversion from single-ended to differential is required. A conversion to
differential signals can be achieved by using an RF-transformer, which provides a center tap. Best performance is
achieved in differential mode.
Mini Circuits
T4–1
49.9 Ω
THS1209
R
AINP
200 Ω
C
R
AINM
C
10 µF
+
REFOUT
Figure 36. Transformer Coupled Input
29
www.ti.com
SLAS288B – JULY 2000 – REVISED DECEMBER 2002
DEFINITIONS OF SPECIFICATIONS AND TERMINOLOGY
Integral Nonlinearity
Integral nonlinearity refers to the deviation of each individual code from a line drawn from zero through full scale. The
point used as zero occurs 1/2 LSB before the first code transition. The full-scale point is defined as level 1/2 LSB
beyond the last code transition. The deviation is measured from the center of each particular code to the true straight
line between these two points.
Differential Nonlinearity
An ideal ADC exhibits code transitions that are exactly 1 LSB apart. DNL is the deviation from this ideal value. A
differential nonlinearity error of less than ±1 LSB ensures no missing codes.
Zero Offset
The major carry transition should occur when the analog input is at zero volts. Zero error is defined as the deviation
of the actual transition from that point.
Gain Error
The first code transition should occur at an analog value 1/2 LSB above negative full scale. The last transition should
occur at an analog value 1 1/2 LSB below the nominal full scale. Gain error is the deviation of the actual difference
between first and last code transitions and the ideal difference between first and last code transitions.
Signal-to-Noise Ratio + Distortion (SINAD)
SINAD is the ratio of the rms value of the measured input signal to the rms sum of all other spectral components below
the Nyquist frequency, including harmonics but excluding dc. The value for SINAD is expressed in decibels.
Effective Number of Bits (ENOB)
For a sine wave, SINAD can be expressed in terms of the number of bits. Using the following formula,
N+
(SINAD * 1.76)
6.02
it is possible to get a measure of performance expressed as N, the effective number of bits. Thus, effective number
of bits for a device for sine wave inputs at a given input frequency can be calculated directly from its measured SINAD.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of the first six harmonic components to the rms value of the measured input signal
and is expressed as a percentage or in decibels.
Spurious Free Dynamic Range (SFDR)
SFDR is the difference in dB between the rms amplitude of the input signal and the peak spurious signal.
30
PACKAGE OPTION ADDENDUM
www.ti.com
10-Jun-2014
PACKAGING INFORMATION
Orderable Device
Status
(1)
THS1209IDA
ACTIVE
Package Type Package Pins Package
Drawing
Qty
TSSOP
DA
32
46
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
Op Temp (°C)
Device Marking
(4/5)
-40 to 85
THS1209I
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
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In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
10-Jun-2014
Addendum-Page 2
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