Dear Gangaraju,

I suggest to you links and attached files in topics.

-How simulate SNR,SNDR, and SFDR of ADC with candence??? - EDA Board

www.edaboard.com › ... › Analog Design › Analog Circuit Design

-Sndr cadence - edaboard.com

search.edaboard.com/sndr-cadence.html

-The Designer's Guide Community Forum - How to calculate SNR & SNDR ...

www.designers-guide.org › ... › Simulators › Circuit Simulators

-11-BITS SUB-RANGING ANALOG TO DIGITAL ... - Semantic Scholar

https://pdfs.semanticscholar.org/.../fd84ffcb2f52cc425492f408539... 

-Design of Analog-to-Digital Converter using CMOS Technology

By AESHA SARAMAN ZALA

Best regards

Thank you sir

Dear Gangaraju,

Dr. Mohamed gave some useful references concerning the measurement of the performance parameters of an A/D converters. I would like to add some specific comments on your question. The first comment is that you measure the quantity as you define it. If we want to measure the signal to noise ratio of the A/D converter then it is meant the signal to quantification noise ratio. It is defined by  10 log signal power/ quantization power.  So we apply a sinusoidal waveform with the peak value = VFS/2,

and then sample the sine wave at all possible level of the analog to digital converter.

Then calculate the the quantiztion noise nq(t) as a difference between the input sine wave the output quantized values. Then we calculate the mean square value of the is noise signal, it is the intended noise power nq^2 avearge= nqp,

Finally one gets the S/ N = 10 log ((VFS^2/8)/ nqp), with VFS^2/8)= the signal power.

For the spurious free dynamic range it is defined by the ratio full scal input voltage to the maximum spurious at the output. In this test you need to input a sine wave signal  as before and you perform fft analysis on the output of the A/D converter to analyse it in the frequency domain. Here you may need to increase the sampling rate to increase the resolution of the frequency domain analysis. The just locate the signal and the highest spur and the calculate the required parameter as 20 log ((VFS/2)/ Vspur).

Best wishes

Dear Gangaraju,

With Cadence virtuoso one can use the spectrum measurement utility to calculate all the above said parameters. For this you have to run the transient simulation, plot the respective signal, go to spectrum utility, fill up the FFT parameters and the utility will calculate all the parameters for you. Hope it helps

Arun

Dear Gangaraju Ankathi,

The best way is to use version 6.1.7 of Cadence software. It is enough to apply a sinusoidal input with appropriate frequency, which is calculated from the following equation to the SAR ADC converter:

f_in=(f_sample* M)/N

In this relation, f_sample, M and N demonstrate the sampling frequency, the number of sampled cycles, and the number of samples, respectively. Note that M must be a prime number. Also, N must be a multiple of 2. It should be noted that you should add an ideal digital to analogue converter controlled by a D flip-flop to the end of the converter and evaluate its output. Then simulate the circuit and draw the output waveform (transient time = N/f_sample). On the waveform page, go to the measurement tab and select the spectrum option. Finally, set the number of samples in the window that opens, select the desired sampling window, and press the S button in the Start/ End freq section. Select the desired number of harmonics and finally click on the plot. Dynamic specifications such as SNR, SNDR, SFDR, ENOB, THD, etc are shown to you.