urian
Full Member level 3
Hi,there
I have designed a front-end S/H which used in a 8b 100M pipeline adc.The VDD is 3V and input is 1Vp-p. The S/H is a charge transfer SC circuit with an 60dB amp.
I dont know, however, how to evaluate the S/H when I looking into the simulation result. I compare the diff. output with diff. input and find that the full scale of output is about 30mv lower than the input. And I look at some sample instant and watch the sample output, I also find that there is a input-dependent difference between them from 50mv to 10mv. But I am not sure the sample instant I am looking is exactly the real sample instant the S/H takes, since the clock have about 200ps rise and fall time and I dont know how to exactly define the sample instant.
Finally, I do fft with the output and find that the fundamental bin is 75dB higher than the second high bin. And the fundamental tone has -170 mdB amplitude. Is it the SFDR? If yes, what about the S/H with amplitude difference described above?
Regards
urian
I have designed a front-end S/H which used in a 8b 100M pipeline adc.The VDD is 3V and input is 1Vp-p. The S/H is a charge transfer SC circuit with an 60dB amp.
I dont know, however, how to evaluate the S/H when I looking into the simulation result. I compare the diff. output with diff. input and find that the full scale of output is about 30mv lower than the input. And I look at some sample instant and watch the sample output, I also find that there is a input-dependent difference between them from 50mv to 10mv. But I am not sure the sample instant I am looking is exactly the real sample instant the S/H takes, since the clock have about 200ps rise and fall time and I dont know how to exactly define the sample instant.
Finally, I do fft with the output and find that the fundamental bin is 75dB higher than the second high bin. And the fundamental tone has -170 mdB amplitude. Is it the SFDR? If yes, what about the S/H with amplitude difference described above?
Regards
urian