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Understanding EVAL-AD5933EBZ.

Question asked by lo.rin on Apr 17, 2018
Latest reply on Apr 25, 2018 by leviathan

I am trying to understand EVAL-AD5933EBZ.  Having worked through the documentation primarily the examples in CN0217; I have the following questions.


1) Why does the EVAL board only calibrate for multi-point frequency and not for mid-point frequency. 

2) I could not get Example 1 to work; for R1, R2 and C3 the output was Z = 23Ω.  The documentation states that the AD5933 can measure impedance ranges from 0.1kΩ - 10MΩ; thus, this is under the parameters of the system, is it possible to measure an impedance less than 100Ω?  

3) The Vp-p (output excitation) has an effect on the reading, when testing R1 in example 2 - Vp-p =  0.2V; however, changing Vp-p = 2V produced an error in the Z.  My question is how do we know which output excitation voltage to select. 

4) If I want to measure an impedance from 5kHz - 100kHz for an unknown impedance of 100Ω - 300Ω what Vp-p would I use and would Rcal = (Zmin + Zmax) / 3 = 133Ω? 


Kindly awaiting your assistance.