AD7785 Analog Devices, AD7785 Datasheet - Page 13

• 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

TYPICAL PERFORMANCE CHARACTERISTICS
8388800
8388750
8388700
8388650
8388600
8388550
8388500
8388450
8388482
16
14
12
10
20
10
Figure 8. Excitation Current Matching (210 μA) at Ambient
8
6
4
2
0
Figure 6. Typical Noise Plot (Internal Reference, Gain = 64,
0
(Internal Reference, Gain = 64, Update Rate = 16.7 Hz)
–2.0
0
8388520
–1.2
Figure 7. Noise Distribution Histogram
200
–0.8
8388560
Update Rate = 16.7 Hz)
–0.4
Temperature
MATCHING (%)
8388600
READING NUMBER
400
0
CODE
0.4
8388640
600
0.8
8388680
1.2
800
8388720
1.6
2.0
8388750
1000
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Figure 10. Bias Voltage Generator Power-Up Time vs. Load Capacitance
Figure 9. Excitation Current Matching (1 mA) at Ambient Temperature
3.0
2.5
2.0
1.5
1.0
0.5
20
10
90
80
70
60
50
40
30
20
10
0
0
0
0
0
–1.75 –1.05 –0.70 –0.35
Figure 11. RMS Noise vs. Reference Voltage (Gain = 1)
V
UPDATE RATE = 16.6Hz
T
A
DD
= 25°C
0.5
= 5V
200
1.0
1.5
REFERENCE VOLTAGE (V)
LOAD CAPACITANCE (nF)
400
2.0
MATCHING (%)
0
2.5
0.35
600
3.0
0.70
3.5
1.05
800
4.0
1.40
AD7785
4.5
1.75
1000
5.0