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https://designers-guide.org/forum/YaBB.pl Measurements >> Other Measurements >> Setup/Hold measurements https://designers-guide.org/forum/YaBB.pl?num=1291725913 Message started by haykp on Dec 7th, 2010, 4:45am |
Title: Setup/Hold measurements Post by haykp on Dec 7th, 2010, 4:45am Dear Forum, Could someone describe me how to measure the setup/hold times of the D flip flop with hspice. Thanks, |
Title: Re: Setup/Hold measurements Post by raja.cedt on Dec 7th, 2010, 10:40pm hi, for setup time vary the the delay between the clock and data and find clock to Q delay. Plot delay VS Clock to Q delay, till some delay range clok to Q delay will be constant and after that(means data is coming closer to data) it increases suddenly, this is almost equal to setup time. Thanks. |
Title: Re: Setup/Hold measurements Post by haykp on Dec 7th, 2010, 11:54pm Hi Raja, Thanks for the great feedback!!! Please let me ask some more clarification, meantime I am doing simulations 1) Would you please why the C2Q delay will increase at the end? 2) Could you please point me some reference where from I can read that. 3) Could you please provide me some measures in Hspice for reference. Thanks, Hayk |
Title: Re: Setup/Hold measurements Post by raja.cedt on Dec 8th, 2010, 6:23am hi, 1. Generally flop means regenerative circuit so its response time is exp(t)*vo, so if you have given enough time it will reach ht e rail or else it will take more time to resolve. 2.Cmos Vlsi Design A Systems Perspective 2nd Ed Neil Weste 3. I think you are asking for measurement commands, for this specific application only if you know how to find delay its enough. I have small consolidated measurements list, please give your mail id so that i can send. Thanks. |
Title: Re: Setup/Hold measurements Post by haykp on Dec 8th, 2010, 10:24pm Hi Raja, Thank you for valuable input. My email is haykpet@gmail.com. Actaullly I have one more plea to you :) Would you please comment on hold time measure. Thanks in advance. |
Title: Re: Setup/Hold measurements Post by ywguo on Dec 26th, 2010, 12:45am Hi haykp, There is a feature named bisection if you simulate setup/hold time with Hspice. Please search the manual for details. If you simulate with spectre, there is similar function in spectreMDL. Best Regards, Yawei |
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