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carlgrace

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Posts: 231
Berkeley, CA

Mimcap mismatch in 65nm TSMC
Aug 06^th, 2010, 1:48pm

Hi all,

I'm simulating some matched MIMCAP capacitors using eldo in TSMC 65nm. I'm getting some variation using monte carlo, but not as much as I would expect. Namely, I would expect the caps (based on their sizes) to match to about 0.1%, but the settling value in the switched-cap amplifier I'm simulation is within more like 0.01%. Am I doing something wrong? I'm setting mismatchflag=1 and it looks like I'm getting *some* mismatch, just not as much as I supposed.

Carl

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pancho_hideboo

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Re: Mimcap mismatch in 65nm TSMC
Reply #1 - Aug 7^th, 2010, 3:00am

I can't find out any design issue in your post.

carlgrace wrote on Aug 6^th, 2010, 1:48pm:

I'm simulating some matched MIMCAP capacitors using eldo in TSMC 65nm.
................................................................................
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I'm getting some variation using monte carlo, but not as much as I would expect.
................................................................................
........................
I'm setting mismatchflag=1 and it looks like I'm getting *some* mismatch, just not as much as I supposed.

Confirm std-deviation of MIMCAP as a result of �MonteCarlo Trials.

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Lex Senior Member Offline Posts: 201 Eindhoven, Holland	Re: Mimcap mismatch in 65nm TSMC Reply #2 - Aug 12^th, 2010, 1:41am Can you isolate the problem by only adding mismatch on capacitors and then verify the result? Maybe you can play with the simulators tolerances, to ascertain you're not looking at numerical noise. 0.01% is quite small to be honest.
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carlgrace Senior Member Offline Posts: 231 Berkeley, CA	Re: Mimcap mismatch in 65nm TSMC Reply #3 - Aug 17^th, 2010, 6:42pm Turns out installing an updated version of the kit fixed the problem. �Weird. Thanks for the replies. Carl
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loose-electron Senior Fellow Offline Best Design Tool = Capable Designers Posts: 1638 San Diego California	Re: Mimcap mismatch in 65nm TSMC Reply #4 - Aug 26^th, 2010, 5:10pm carlgrace wrote on Aug 17^th, 2010, 6:42pm: Turns out installing an updated version of the kit fixed the problem. �Weird. Thanks for the replies. Carl Weird? Nope, just bad models. Not to be surprised.
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