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AC simulation convergence issue (Read 885 times)
Senior Member

Posts: 182

AC simulation convergence issue
Mar 15th, 2018, 10:17pm
Hi, I am simulating a long chain of 40 delay cells. Each cell consists of one all pass delay cells and a buffer. There is a coupling cap between buffer and delay cell. Each unit cell has unity gain. After 30 stages the ac gain shows rough peaks showing convergence issue. I see a zig-zag curve instead of smooth one. How to fix this issue? Please help.
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Ken Kundert
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Posts: 2294
Silicon Valley
Re: AC simulation convergence issue
Reply #1 - Mar 15th, 2018, 11:03pm
Dude! 182 post and you don't know that you should not post simulation questions on a design board?!?

Only design questions go on the design boards.

Your question is rather vague, but it sounds like you are seeing trapezoidal rule rining. Try switching the method to gear2only.

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