AD7156 Analog Devices, AD7156 Datasheet - Page 9

• Manufacturer Part Number: AD7156
• Manufacturer: Analog Devices

Specifications of AD7156

• Resolution (bits): 12bit
• # Chan: 2
• Sample Rate: 100SPS
• Interface: I²C/Ser 2-Wire,Ser
• Analog Input Type: Capacitive
• Ain Range: 0.5 pF,1 pF,2 pF,4 pF
• Pkg Type: CSP

Figure 12. Capacitance Input Gain Error vs. Resistance EXC to GND,
Figure 10. Capacitance Input Gain Error vs. Resistance CIN to GND,
Figure 11. Capacitance Input Gain Error vs. Resistance CIN to GND,
–0.2
–0.4
–0.6
–0.8
–1.0
–10
–10
0.2
–2
–4
–6
–8
–2
–4
–6
–8
2
0
2
0
0
0.1
1
1
V
V
V
3.3V
3.3V
DD
DD
1.8V
DD
= 1.8 V and 3.3 V, CIN to EXC = 3 pF
= 1.8 V and 3.3 V, CIN to EXC = 9 pF
= 1.8 V and 3.3 V, CIN to EXC = 3 pF
RESISTANCE EXC TO GROUND (MΩ)
1
RESISTANCE CIN TO GND (MΩ)
RESISTANCE CIN TO GND (MΩ)
10
10
1.8V
1.8V
3.3V
10
100
100
100
1k
1k
1k
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Figure 13. Capacitance Input Gain Error vs. Resistance EXC to GND,
Figure 15. Capacitance Input Gain Error vs. Parallel Resistance,
–0.2
–0.4
–0.6
–0.8
–1.0
Figure 14. Capacitance Input Gain Error vs. Serial Resistance,
–10
–20
–30
–40
–50
0.2
–1
–2
–3
–4
–5
–6
–7
10
0
1
0
0
0.1
0
1
1.8V
V
V
V
3.3V
DD
DD
DD
= 1.8 V and 3.3 V, CIN to EXC = 9 pF
20
= 1.8 V and 3.3 V, CIN to EXC = 3 pF
= 1.8 V and 3.3 V, CIN to EXC = 3 pF
RESISTANCE EXC TO GROUND (MΩ)
1
3.3V
PARELLEL RESISTANCE (MΩ)
SERIAL RESISTANCE (kΩ)
10
1.8V
40
10
1.8V
60
100
100
80
3.3V
AD7156
100
1k
1k