250 kSPS, 12-Bit Impedance Converter,
Programmable output peak-to-peak excitation voltage
to a max frequency of 100 kHz
Programmable frequency sweep capability with
serial I2C® interface
Frequency resolution of 27 bits (<0.1 Hz)
Impedance measurement range from 100 Ω to 10 MΩ
Phase measurement capability
System accuracy of 0.5%
2.7 V to 5.5 V power supply operation
Temperature range −40°C to +125°C
16-lead SSOP package
Bioelectrical impedance analysis
Complex impedance measurement
Corrosion monitoring and protection equipment
Biomedical and automotive sensors
Material property analysis
Fuel/battery cell condition monitoring
The AD5934 is a high precision impedance converter system
solution which combines an on-board frequency generator with
a 12-bit, 250 kSPS, analog-to-digital converter (ADC). The
frequency generator allows an external complex impedance to
be excited with a known frequency. The response signal from
the impedance is sampled by the on-board ADC and a discrete
Fourier transform (DFT) is processed by an on-board DSP
engine. The DFT algorithm returns a real (R) and imaginary (I)
data-word at each output frequency.
The magnitude of the impedance and relative phase of the
impedance at each frequency point along the sweep is easily
calculated using the following two equations:
Magnitude = R2 + I2
Phase = Tan−1(I / R)
Table 1. Related Devices
Part No. Description
AD5933 2.7 V to 5.5 V. 1 MSPS, 12-bit impedance, with
internal temperature sensor, 16-lead SSOP.
FUNCTIONAL BLOCK DIAGRAM
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