AD7921 Analog Devices, AD7921 Datasheet - Page 14

• Manufacturer Part Number: AD7921
• Description: 2-Channel, 2.35 V to 5.25 V, 250 kSPS, 12-Bit A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7921

• Resolution (bits): 12bit
• # Chan: 2
• Sample Rate: 250kSPS
• Interface: Ser,SPI
• Analog Input Type: SE-Uni
• Ain Range: Uni Vdd
• Adc Architecture: SAR
• Pkg Type: SOP,SOT

AD7911/AD7921
Figure 16. THD vs. Analog Input Frequency for Various Source Impedances
–0.2
–0.4
–0.6
–0.8
–1.0
–0.2
–0.4
–0.6
–0.8
–1.0
–25
–35
–45
–55
–65
–75
–85
–95
1.0
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
0
0
10
0
0
V
F
TEMPERATURE = 25°C
R
V
F
TEMPERATURE = 25°C
DD
SAMP
IN
DD
SAMP
512
= 2.7V
512
= 0Ω
= 2.7V
= 250kSPS
Figure 15. AD7921 DNL Performance
Figure 14. AD7921 INL Performance
R
= 250kSPS
IN
1024
1024
= 500Ω
R
IN
= 10Ω
R
1536
1536
FREQUENCY (kHz)
R
IN
IN
= 50Ω
= 1kΩ
CODE
CODE
2048
2048
100
2560
2560
R
IN
= 100Ω
3072
3072
V
DD
3584
3584
= 3.6V
4096
4096
1k
Rev. A | Page 14 of 28
Figure 17. THD vs. Analog Input Frequency for Various Supply Voltages
–74
–76
–78
–80
–82
–84
–86
–88
180
160
140
120
100
80
60
40
20
0
2.0
10
V
V
DD
Figure 18. Shutdown Current vs. Supply Voltage
DD
= 2.35V
= 3.6V
2.5
3.0
V
DD
SUPPLY VOLTAGE (V)
FREQUENCY (kHz)
= 4.75V
TEMPERATURE = –40°C
3.5
TEMPERATURE = +85°C
100
TEMPERATURE = +25°C
V
4.0
DD
V
DD
= 2.7V
= 5.25V
4.5
5.0
5.5
1k