AD7938 Analog Devices, AD7938 Datasheet - Page 11

• 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

Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
Figure 4. PSRR vs. Supply Ripple Frequency Without Supply Decoupling
= 25°C, unless otherwise noted.
–100
–110
–120
–60
–70
–80
–90
–70
–75
–80
–85
–90
–95
80
70
60
50
40
30
20
10
Figure 6. AD7938 SINAD vs. Analog Input Frequency
0
0
100mV p-p SINE WAVE ON V
NO DECOUPLING
DIFFERENTIAL/SINGLE-ENDED MODE
INTERNAL/EXTERNAL REFERENCE
V
Figure 5. AD7938 Channel-to-Channel Isolation
F
RANGE = 0 TO V
DIFFERENTIAL MODE
DD
SAMPLE
100
= 5V
100
EXT REF
INT REF
210
= 1.5MSPS
200
for Various Supply Voltages
SUPPLY RIPPLE FREQUENCY (kHz)
200
300
REF
NOISE FREQUENCY (kHz)
300
FREQUENCY (kHz)
410
400
500
400
DD
V
AND/OR V
DD
600
610
= 3V
500
V
DD
700
DRIVE
= 5V
600
810
800
700
900
1010
1000
800
Rev. C | Page 11 of 36
–100
–110
–0.2
–0.4
–0.6
–0.8
–1.0
–0.2
–0.4
–0.6
–0.8
–1.0
–10
–20
–30
–40
–50
–60
–70
–80
–90
1.0
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
0
0
0
0
0
Figure 8. AD7938 Typical DNL @ V
500
500
Figure 9. AD7938 Typical INL @ V
Figure 7. AD7938 FFT @ V
1000
1000
1500
1500
FREQUENCY (kHz)
2000
CODE
2000
CODE
2500
2500
AD7938/AD7939
DD
V
DIFFERENTIAL MODE
V
DIFFERENTIAL MODE
4096 POINT FFT
V
F
F
SINAD = 70.94dB
THD = –90.09dB
DIFFERENTIAL MODE
= 5 V
DD
SAMPLE
IN
DD
DD
DD
DD
= 49.62kHz
= 5V
3000
= 5V
3000
= 5V
= 5 V
= 5 V
= 1.5MSPS
3500
3500
4000
4000