Datasheet

REV. 0–2–
AD7738–SPECIFICATIONS
Parameter Min Typ Max Unit Test Conditions/Comment
ADC PERFORMANCE—
CHOPPING ENABLED
Conversion Time Rate 372 12190 Hz Configure via Conversion Time Register
No Missing Codes
1
24 Bits FW ≥ 6 (Conversion Time ≥ 165 µs)
See Typical Performance Characteristics
Output Noise See Table I
Resolution See Tables II and III
Integral Nonlinearity (INL) ± 0.0015 % of FSR AIN Range = ± 2.5 V
± 0.0015 % of FSR AIN Range = ± 1.25 V
Offset Error (Unipolar, Bipolar)
2
± 10 µV Before Calibration
Offset Drift vs. Temperature
1
± 280 nV/°C
Gain Error
2
± 0.2 % Before Calibration
Gain Drift vs. Temperature
1
± 2.5 ppm of FS/ⴗC
Positive Full-Scale Error
2
± 0.2 % of FSR Before Calibration
Positive Full-Scale Drift vs. Temperature
1
± 2.5 ppm of FS/ⴗC
Bipolar Negative Full-Scale Error
3
± 0.0030 % of FSR After Calibration
3
Common-Mode Rejection 80 100 dB At DC, AIN = 1 V
Power Supply Rejection 70 80 dB At DC, AIN = 1 V
ADC PERFORMANCE—
CHOPPING DISABLED
Conversion Time Rate 737 15437 Hz Configure via Conversion Time Register
No Missing Codes
1
24 Bits FW ≥ 8 (Conversion Time ≥ 117 µs)
See Typical Perfomance Charateristics
Output Noise See Table IV
Resolution See Tables V and VI
Integral Nonlinearity (INL) ± 0.0015 % of FSR
Offset Error (Unipolar, Bipolar)
4
± 1mVBefore Calibration
Offset Drift vs. Temperature ± 1.5 µV/ⴗC
Gain Error
2
± 0.2 % Before Calibration
Gain Drift vs. Temperature ± 2.5 ppm of FS/ⴗC
Positive Full-Scale Error
2
± 0.2 % of FSR Before Calibration
Positive Full-Scale Drift vs. Temperature ± 2.5 ppm of FS/ⴗC
Bipolar Negative Full-Scale Error
3
± 0.0030 % of FSR After Calibration
3
Common-Mode Rejection 75 dB At DC, AIN = 1 V
Power Supply Rejection 65 dB At DC, AIN = 1 V
ANALOG INPUTS
Analog Input Voltage Ranges
1, 5
± 2.5 V Range –2.9 ± 2.5 +2.9 V
+2.5 V Range 0 0 to 2.5 2.9 V
± 1.25 V Range –1.45 ± 1.25 +1.45 V
+1.25 V Range 0 0 to 1.25 1.45 V
± 0.625 V Range –725 ± 625 +725 mV
+0.625 V Range 0 0 to 625 725 mV
AIN, AINCOM Common-Mode Voltage
1
0.2 AV
DD
– 0.3 V
AIN, AINCOM Input Current
6
200 nA Only One Channel, Chop Disabled
AIN to MUXOUT On Resistance
1
200 Ω
REFERENCE INPUT
REFIN(+) to REFIN(–) Voltage
1, 7
2.475 2.5 2.525 V
NOREF Trigger Voltage 0.5 V NOREF Bit in Channel Status Register
REFIN(+), REFIN(–)
Common-Mode Voltage
1
0AV
DD
V
Reference Input Current
8
400 µA
SYSTEM CALIBRATION
1, 9
Full Scale Calibration Limit +1.05 ⫻ FS V
Zero Scale Calibration Limit –1.05 ⫻ FS V
Input Span 0.8 ⫻ FS 2.1 ⫻ FS V
(–40ⴗC to +105ⴗC, AV
DD
= 5 V ⴞ 5%, DV
DD
= 2.7 V to 3.6 V or 5 V ⴞ 5%,
REFIN(+) = 2.5 V, REFIN(–) = 0 V, AINCOM = 2.5 V, MUXOUT(+) = ADCIN(+), MUXOUT(–) = ADCIN(–), Internal Buffer ON, AIN Range = ⴞ1.25 V,
f
MCLK
= 6.144 MHz; unless otherwise noted.)