The measurement of PSRR for a 10-bit SAR ADC

[howardtang85]

Hi all,

I have designed a 10-bit SAR ADC. Now I need to measure the PSRR performance of the ADC.

I read some articles. It says I will need to inject a 100mV sine wave to the power supply and ground the input. Capture the output code and process it with FFT. I have done so and get a spur of -72dB at 1kHz (the supply noise is 1kHz). May I know how to calculate the PSRR in this case?


Thanks!

 

[crutschow]

The PSRR is referenced to the full-scale input voltage of the ADC. What is the -72dB referenced to?

 

[goodboy_pl]

howardtang85,
you must also inject the 100mv signal only to the ADC input and measure its power using fft method, then subtract result of the first measurement from second.

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