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AD5933 used to measure very large impedances

Question asked by verysmallcap on Jan 28, 2016
Latest reply on Feb 8, 2016 by musach

Hello AD5933 users.
Has anyone used a AD5933 supplemented with a suitable external transimpedance input stage (TIA) to measure very large impedances?

As an example the TIA could be a AD823 with a 10Mohm feedback resistor, set to get the noise budget right.  Our requirement is to measure capacitances in the 10s -100s fF range, amounting to an impedance magnitude of 10s -100s Mohms (at 100kHz).