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Measurements >> Other Measurements >> Setup/Hold measurements
https://designers-guide.org/forum/YaBB.pl?num=1291725913

Message started by haykp on Dec 7^th, 2010, 4:45am

Title: Setup/Hold measurements
Post by haykp on Dec 7^th, 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 7^th, 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 7^th, 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 8^th, 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 8^th, 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 26^th, 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