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Simulators >> Circuit Simulators >> Monte Carlo simulation issues
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Message started by trashbox on Jun 26^th, 2009, 5:24am

Title: Monte Carlo simulation issues
Post by trashbox on Jun 26^th, 2009, 5:24am

Hi all,
I'm using hspice to run Monte Carlo simulation and puzzled about the following questions:
#1. How many iterations is ok for MC simulation? If I set iteration very large, it'll spend too much simulation time.

#2. The foundry documentation shows I should set PROCESS Variability and MISMATCH respectively. So what's the difference between PROCESS Variability and MISMATCH? I ever think mismatch is the result of process variability.

#3. If I run MC simulation, should I also set corner? What's the difference between corner (fast/slow/typical) and Monte Carlo?

Thanks in advance!

Title: Re: Monte Carlo simulation issues
Post by boe on Jun 26^th, 2009, 5:54am

Hi trashbox,
#1: 100 runs is usually a good choice.
#2: Mismatch is local variation (different for different instances), Process variation is global variation (all devices see same variation - as in corner analysis)
#3: corner changes process parameters for all devices to worst-case values; MC process variation varies global process parameters statistically.

BOE

Title: Re: Monte Carlo simulation issues
Post by raja.cedt on Jun 26^th, 2009, 11:27pm

hi,
the main difference between monte and corner simulation is in corner all devices has same characteristics(means ss corner every device is slow) but in monte you may have different lets say for a differential amplifier in corner simulation at least you wont see large offset voltage but in monte you may have one of the differential pair is slow another is fast so you will get worst offset voltage.

Thanks,
Rajasekhar.

Title: Re: Monte Carlo simulation issues
Post by trashbox on Jun 28^th, 2009, 6:48pm

Hi boe and raja.cedt!
Thanks very much. I got it. :-)