AD7938 Analog Devices, AD7938 Datasheet - Page 12

• Manufacturer Part Number: AD7938
• Description: 8-Channel, 1.5 MSPS, 12-Bit Parallel ADCs with a Sequencer
• Manufacturer: Analog Devices

Specifications of AD7938

• Resolution (bits): 12bit
• # Chan: 8
• Sample Rate: 1.5MSPS
• Interface: Byte,Par
• Analog Input Type: Diff-Uni,SE-Uni
• Ain Range: (2Vref) p-p,5V p-p,Uni (Vref),Uni (Vref) x 2,Uni 2.5V,Uni 5.0V
• Adc Architecture: SAR
• Pkg Type: CSP,QFP

AD7938/AD7939
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
–3.5
–4.0
–4.5
–5.0
–1
12
11
10
4
3
2
1
0
9
8
7
6
0
0.25 0.50
0
0
SINGLE-ENDED MODE
Figure 10. AD7938 DNL vs. V
0.5
0.5
Figure 12. AD7938 Offset vs. V
Figure 11. AD7938 ENOB vs. V
0.75
V
DD
1.0
= 5V
1.0
1.00
V
DD
DIFFERENTIAL MODE
1.5
SINGLE-ENDED MODE
1.25
= 3V
1.5
V
DIFFERENTIAL MODE
DD
V
V
V
REF
REF
REF
1.50
2.0
= 3V
V
SINGLE-ENDED MODE
DD
(V)
(V)
(V)
POSITIVE DNL
NEGATIVE DNL
2.0
V
REF
= 3V
1.75
DD
V
2.5
DD
SINGLE-ENDED MODE
for V
= 5V
= 5V
2.00
REF
REF
DD
2.5
3.0
= 3 V
2.25
3.0
3.5
2.50
2.75
4.0
3.5
Rev. C | Page 12 of 36
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
Figure 14. CMRR vs. Ripple Frequency with V
120
110
100
90
80
70
60
2046
0
10k Samples @ V
0
DIFFERENTIAL MODE
DIFFERENTIAL MODE
Figure 13. AD7938 Histogram of Codes for
200
2047
DD
RIPPLE FREQUENCY (kHz)
400
= 5 V with the Internal Reference
2048
CODES
9997
CODE
600
2049
3 CODES
800
DD
= 5 V and 3 V
2050
Data Sheet
INTERNAL
1000
REF
1200