Impedance measurement range of AD5940

Question

Hello, 
 I want to measure small variations in impedance. Impedance of sensor is around 150 Ohms and variations will be &plusmn;20 Ohms around it. 
 Measurements are to be conducted at frequencies in range 150 kHz to 200 kHz. 
 Is there a way to control the range of impedance measured by AD5940, so maximum resolution is achieved? 
 RTIA can be set according to the minimum unknown impedance. Can we account for the maximum unknown impedance also? 
 
 Thanks in advance 
 Rasika

Akila · Answer

AD5940 can measure impedance from 1 Ohm to 10MOhms.

Snorlax · Answer

Satish321 said: I am using AD5933, whose unknown impedance range is from 1 Kohm to 10 Mega ohm. 
 Not really - the range depends on Rfb value, excitation voltage and PGA gain programmed into the AD5933. The range can be expanded arbitrarily (within reasonable practical limitations) using the AFE - like the one that is present in the evaluation board.

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Impedance measurement range of AD5940