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Design >> Analog Design >> Clock generator for latched comparator
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Message started by gsensor on Apr 24^th, 2012, 3:38pm

Title: Clock generator for latched comparator
Post by gsensor on Apr 24^th, 2012, 3:38pm

Hi guys,

I'm currently designing a latched comparator working with a 200 MHz ideal clock in Spectre Simulator with CMOSP13 IBM technology. I don't know if its best to implement this 200 MHz clock on-chip or to have an output signal linked to an off-chip clock generator. As I have no experience with circuit working with a clock, I don't know which option is best in terms of precision ? My guess is going with an on-chip clock, but which topology, taking in consideration low complexity and low space ? A VCO, or do I need a PLL for this frequency ?

Thanks for your help,
gsensor

Title: Re: Clock generator for latched comparator
Post by loose-electron on Apr 24^th, 2012, 5:23pm

external crystal generated clock if possible

Title: Re: Clock generator for latched comparator
Post by gsensor on Apr 25^th, 2012, 11:34am

Why ? Isn't an external clock more imprecise due to propagation delays and external noise, than an on-chip clock with a good layout design ?

Title: Re: Clock generator for latched comparator
Post by boe on Apr 25^th, 2012, 1:37pm

Gsensor,
crystals are resonators with very high Q, which minimizes errors.

- B O E

Title: Re: Clock generator for latched comparator
Post by gsensor on Apr 26^th, 2012, 8:14am

Ok, thanks guys for your advice. I will use an external crystal oscillator.

Title: Re: Clock generator for latched comparator
Post by loose-electron on May 5^th, 2012, 10:41am

Q of an external crystal is 10E5, which you can not do with an internal oscillator.