Analog Devices AD5934 Manual page 18

AD5934
Impedance Range 3 (10 kΩ to 100 kΩ)
The following conditions were used to conduct the tests shown
in Figure 24:
Output excitation voltage = 2 V p-p
Calibration impedance value, Z
PGA gain = ×1
Supply voltage = 3.3 V
Current-to-voltage amplifier gain resistor = 10 kΩ
0.3
R = 10kΩ
FB
CALIBRATION IMPEDANCE = 10kΩ
T = 25°C
A
0.2
0.1
0
–0.1
–0.2
–0.3
10
FREQUENCY (kHz)
Figure 24. Impedance Range 3 Typical % Impedance Error over Frequency
Impedance Range 4 (100 kΩ to 1 MΩ)
The following conditions were used to conduct the tests shown
in Figure 25:
Output excitation voltage = 2 V p-p
Calibration impedance value, Z
PGA gain = ×1
Supply voltage = 3.3 V
Current-to-voltage amplifier gain resistor = 100 kΩ
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
R = 100kΩ
FB
–3.0
CALIBRATION IMPEDANCE = 100kΩ
T = 25°C
A
–3.5
10
FREQUENCY (kHz)
Figure 25. Impedance Range 4 Typical % Impedance Error over Frequency
= 10 kΩ
CALIBRATION
50kΩ
100kΩ
35 60 100
= 100 kΩ
CALIBRATION
500kΩ
1MΩ
35 60 100
Impedance Range 5 (1 MΩ to 2 MΩ)
The following conditions were used to conduct the tests shown
in Figure 26:
Output excitation voltage = 2 V p-p
Calibration impedance value, Z
PGA gain = ×1
Supply voltage = 3.3 V
Current-to-voltage amplifier gain resistor = 100 kΩ
3
R
FB
CALIBRATION IMPEDANCE = 1MΩ
T
A
1
–1
–3
–5
–7
–9
Figure 26. Impedance Range 5 Typical % Impedance Error over Frequency
Impedance Range 6 (9 MΩ to 10 MΩ)
The following conditions were used to conduct the tests shown
in Figure 27:
Output excitation voltage = 2 V p-p
Calibration impedance value, Z
PGA gain = ×1
Supply voltage = 3.3 V
Current-to-voltage amplifier gain resistor = 9 MΩ
4
R
FB
CALIBRATION IMPEDANCE = 10MΩ
T
2
A
0
–2
–4
–6
–8
–10
Figure 27. Impedance Range 6 Typical % Impedance Error over Frequency
Rev. A | Page 18 of 40
= 100 kΩ
CALIBRATION
= 1MΩ
= 25°C
1.5MΩ
2MΩ
10
35 60
FREQUENCY (kHz)
= 9 MΩ
CALIBRATION
= 10MΩ
= 25°C
9.5MΩ
10MΩ
10 35 60
FREQUENCY (kHz)
100
100