AD7787 Analog Devices, AD7787 Datasheet - Page 9

• Manufacturer Part Number: AD7787
• Description: Low Power, 2-Channel 24-Bit Sigma-Delta ADC
• Manufacturer: Analog Devices

Specifications of AD7787

• Resolution (bits): 24bit
• # Chan: 2
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni,SE-Bip,SE-Uni
• Ain Range: (2Vref) p-p,(Vref) p-p,Uni (Vref)
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

TYPICAL PERFORMANCE CHARACTERISTICS
Figure 8. Typical Noise Plot with 16.6 Hz Update Rate (CDIV1 = CD1V0 = 0)
8388619
8388591
–100
–110
–120
100
8388591
–10
–20
–30
–40
–50
–60
–70
–80
–90
80
60
40
20
Figure 7. Noise Distribution Histogram (CDIV1 = CDIV0 = 0)
0
0
Figure 6. Frequency Response with 16.6 Hz Update Rate
0
0
V
V
9.5Hz UPDATE RATE
T
RMS NOISE = 1µV
V
T
A
DD
REF
A
DD
= 25°C
= 25°C, RMS NOISE = 1µV
= 3V
= 3V, V
= 2.048V
20
200
REF
40
= 2.048V, 9.5Hz UPDATE RATE
60
FREQUENCY (Hz)
400
READ NO.
CODE
80
600
100
120
800
140
8388619
160
1000
Rev. 0 | Page 9 of 20
Figure 9. Noise Histogram for Clock Divide-by-8 Mode (CDIV0 = CDIV1 = 1)
8388616
8388592
Figure 10. Noise Plot in Clock Divide-by-8 Mode (CDIV0 = CDIV1 = 1)
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3.0
2.5
2.0
1.5
1.0
0.5
9
8
7
6
5
4
3
2
1
0
0
0
0
V
V
1.1875Hz UPDATE RATE
T
RMS NOISE = 1.25µF
V
UPDATE RATE = 16.6Hz
T
DD
REF
A
V
1.1875Hz UPDATE RATE
T
DD
A
DD
A
= 25°C
= 25°C
0.5
= 3V
= 25°C, RMS NOISE = 1.25µF
= 5V
Figure 11. RMS Noise vs. Reference Voltage
= 2.048V
= 3V, V
1.0
20
REF
= 2.048V
1.5
2.0
40
READ NO.
V
CODE
REF
2.5
(V)
3.0
60
3.5
4.0
80
4.5
AD7787
8388616
5.0
100