Fault Analysis methods for flash ADCs

[rafgamo]

Can someone tell me some of the best methods for linearity testing of Flash ADCs?

 

[erikl]

Re: Linearity Analysis methods for flash ADCs

What you want is not a fault analysis (a term often used in digital circuit analyses with quite different purpose), but a linearity analysis method.

I think the simplest method is to use an ideal (linear) saw tooth input (or a stair case input with 1 LSB step distances) and check the output against the input - either manually, or via a wave plot comparison between your input waveform with the back-converted analog waveform of your ADC's output by an ideal DAC (plotting the difference), or a (more or less automatic) text comparison of your digital output with the digital output of an ideal ADC running in parallel to your ADC.

 

[:Dark_Force]

Connect an ultra-pure oscillator to your ADC and plot the FFT of the adc output. Linearity errors show up as harmonics that are not present in the oscillator output. In order to measure this you have to know the output spectrum of the oscillator of course!
There is also some literature on the internet about testing data converters, e.g. https://www.analog.com/library/analogdialogue/archives/39-06/Chapter%205%20Testing%20Converters%20F.pdf