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Is there some relation between clock transition and setup/hold time for a D flip-flop

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alanzheng

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hello, all:

My question is:

Is there some relation between clock transition and setup/hold time for a D flip-flop? Or setup/hold time is constant regardless of clock transition time?

Thanks!
 

Re: clock transition time vs setup/hold time of a DFF

Hi,
The answer is yes, of cause, setup time depends on clock transition time. You can see it in detailed STA tool's LOG as some additional to path delay. Besides, you can see it in liberty file:
pin ( Q ) {
direction : output;
timing () {
related_pin : "CLK" ;
Click to expand...
And, mostly important: look at DFF schematic :) Analog Design exp rules
 

Re: clock transition time vs setup/hold time of a DFF

Hi,

Setup and Hold time depends upon both Clock as well as Data transition time.

Regards,
 

Re: clock transition time vs setup/hold time of a DFF

yes it does depend upon the clock transition time.If u see the cell library of liberty u can see that the set up time of a flip-flop depends up on two things
a)input transition time of D-flip flop and
b)clock transition time.
the table for set-up time comprises of the above two.

now the reason is if u see the cmos transistor level D-ff.understandin the requirment for setup is important.SET-UP means to establish.We want the driving element of the D flip-flop which may be another flip flop should establish the data before setup time .
if clock transistion time is more, the D-i/p may get that much extra time to setup at the input. so the setup time decreases with increase in clock transistion time and vice-versa.
 

Re: clock transition time vs setup/hold time of a DFF

i m not sure on the above comment................sorry......
 
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    Kuxx

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Re: clock transition time vs setup/hold time of a DFF

Is it true for hold time?
I mean hold time also depends on data and clock transition?

-Vid31
 

Re: clock transition time vs setup/hold time of a DFF

arjun1110 said:
Hi,

Setup and Hold time depends upon both Clock as well as Data transition time.

Regards,
Click to expand...

How ????? Can you explain in detail? how hold time depends on clock?
 

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