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AD7745 External Excitation

Question asked by baala on Dec 9, 2013
Latest reply on Dec 13, 2013 by Holger

Hi,

 

I have to measure the capacitance of three capacitive sensors which are placed together. AD7745 seems ideal for the application. But if I use 3 different excitation sources(one in each chip of AD7745),even if there is a small difference in the frequencies of these excitation voltage, there is a chance of beating, since the cables from all these sensors are bunched together. So  is it possible to use an external excitation source(Vdd/2 ; 32 kHz)  common for all these sensors?

The output from each of the sensor goes to the CIN pin of each AD7745.

NB: I am planning to use it with range extension circuit.

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