AD7785 Analog Devices, AD7785 Datasheet - Page 4

• Manufacturer Part Number: AD7785
• Description: 3-Channel, Low Noise, Low Power, 20-Bit ?-? ADC with On-Chip In-Amp and Reference
• Manufacturer: Analog Devices

Specifications of AD7785

• Resolution (bits): 20bit
• # Chan: 3
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: ± (Vref/Gain)
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

AD7785
Parameter
REFERENCE
EXCITATION CURRENT SOURCES
TEMPERATURE SENSOR
BIAS VOLTAGE GENERATOR
INTERNAL/EXTERNAL CLOCK
LOGIC INPUTS
Internal Reference
External Reference
(IEXC1 and IEXC2)
Output Current
Initial Tolerance at 25°C
Drift
Current Matching
Drift Matching
Line Regulation (V
Load Regulation
Output Compliance
V
V
Internal Clock
External Clock
CS
Accuracy
Sensitivity
BIAS
BIAS
Internal Reference Initial Accuracy
Internal Reference Drift
Power Supply Rejection
External REFIN Voltage
Reference Voltage Range
Absolute REFIN Voltage Limits
Average Reference Input Current
Average Reference Input Current
Normal Mode Rejection
Common-Mode Rejection
Frequency
Duty Cycle
Frequency
Duty Cycle
2
V
V
INL
INH
Generator Start-Up Time
Drift
, Input Low Voltage
, Input High Voltage
2
DD
)
2
2
2
AD7785B
1.17 ± 0.01%
4
15
85
2.5
0.1
AV
GND − 30 mV
AV
400
±0.03
Same as for analog inputs
100
10/210/1000
±5
200
±0.5
50
2
0.2
AV
AV
GND − 30 mV
±2
0.81
AV
See Figure 10
64 ± 3%
50:50
64
45:55 to 55:45
0.8
0.4
2.0
DD
DD
DD
DD
DD
/2
+ 30 mV
− 0.65
− 1.1
1
Rev. 0 | Page 4 of 32
Unit
V min/max
ppm/°C typ
ppm/°C max
dB typ
V nom
V min
V max
V min
V max
nA/V typ
nA/V/°C typ
dB typ
μA nom
% typ
ppm/°C typ
% typ
ppm/°C typ
%/V typ
%/V typ
V max
V max
V min
°C typ
mV/°C typ
V nom
ms/nF typ
kHz min/max
% typ
kHz nom
% typ
V max
V max
V min
Test Conditions/Comments
AV
REFIN = REFIN(+) − REFIN(−)
When V
limited to 0.9 × V
Matching between IEXC1 and IEXC2; V
AV
10 μA or 210 μA currents selected
1 mA currents selected
Applies if user calibrates the temperature sensor
Applies if user calibrates the temperature sensor
Dependent on the capacitance on the AIN pin
A 128 kHz external clock can be used if the
divide-by-2 function is used
(Bit CLK1 = CLK0 = 1)
Applies for external 64 kHz clock; a 128 kHz
clock can have a less stringent duty cycle
DV
DV
DV
DD
DD
DD
DD
DD
= 4 V, T
= 5 V ± 5%
= 5 V
= 3 V
= 3 V or 5 V
REF
= AV
A
= 25°C
DD
REF
, the differential input must be
/gain if the in-amp is active
OUT
= 0 V