pipeline adc problem- the performance will decrease

[lhlbluesky]

problem with pipelined adc

for a pipelined adc, the performance of it (SNR\SNDR\INL\DNL\THD etc)will decrease with the increasing of input sine frequency; then what's the reason?

for a 10bit 15M pipelined adc(just for circuit simulation, not for the chip test), its ENOB=9.8 at 300k input sine frequency, while when input sine frequency increases to 7.5M or so, its ENOB=7.8, why? Why ENOB decreases so much? and what are the possible reasons?

pls give me some advice,thanks everyone for your reply.

 

[Usman Hai]

Re: pipeline adc problem

At higher frequency, THD increases due to many reasons. Most important is switch nonlinear ON resistance. This harmonic distortion increases the SNDR of the ADC. And as you might already know ENOB=(SNDR+1.76)/6.02.
So, SNDR decreases, ENOB decreases.

 

[lhlbluesky]

pipeline adc problem

are there more advice or reasons? pls tell me more, thanks.

 

[lhlbluesky]

pipeline adc problem

are there more advice or reasons? pls tell me more, thanks all.

 

[lhlbluesky]

pipeline adc problem

can anyone help me more,pls?