AD5933 Application Notes - Question


I have an application to measure an impedance that is in the Gigaohm range.  I am experimenting with the AD5933 / AD5933 Evaluation Board.  Are there application notes regarding use of this chip in excess of the 10M that is on the datasheet.  Ideally I would like to sample at the lower frequency range. 

Any feedback regarding chip limitations or design suggestions that would allow for more measurement range would be welcome and appreciated.

Kind Regards

  • Measuring impedance in the Gigaohm range is a tricky business, especially the AC measurements, as the impedance in this range in combination with parasitic capacitance of the wires tends to produce long transient times. It is possible to use the AD5933 for measurements at low frequencies by reducing the MCLK, but, depending on the details of your application, you could probably do something else.

    Hard to suggest any designs without knowing why AC measurements are required in this range of impedance in the first place - it has to be some rather special application.