Hello, Miguel-san,
Thank you very much for your reply!
EVAL-AD5933 board revision is Rev. C.
My apology is wrong information about targeted Resistor and Impedance value in my 1st thread message.
Resgistor value is about 940 to 980ohm.
So, targeted impedance is roughly 100 to 980ohm.
I'v been trying some setting condition on online simulator (also your recommended Rfb value) , but result is still about 30% error.
Analog Devices: Interactive Design Tools: Impedance Measurement:
Targeted small capacitor (0.2nF, 1nF, 5nF) are phase -0.07 to -2 degree.
But AD5933 has phase error about 0.18 to -0.9 degree. (according to Datasheet page 10, Figure13)
Actuary the customer had measured there is phase error about +/-0.3 degree on EVAL-AD5933.
So I assume that it is difficult to measure such a small capacitor, isn't it?
I would like to appreciate if you have any other advice.
Best regards,
Sofy