Diffrence between hold time and D-Q delay?

[jayjavan2003]

Hi, I could not understand the difference between hold time and D to Q delay time in DFF and what factors affects hold time?

 

[sivamit]

Hi, I could not understand the difference between hold time and D to Q delay time in DFF and what factors affects hold time?

Hi,
Hold Time (Th) is the minimum time interval for which the input signal must be stable (unchanging) following the sampling event of the clock for the input signal to be recognized correctly.

I think D-Q dely is 'latency'.But it is not 100% correct I am sure. Lets wait for others reply.

You can also refer these links..

**broken link removed**
https://www.eecs.berkeley.edu/~newton/Classes/CS150sp97/lectures/week2_1/tsld006.htm
https://www.velocityreviews.com/forums/t22483-setup-vs-clocktooutput-time-vs-hold-time.html

-Sharon

 

[gliss]

Do you mean Clock-to-Q delay instead of D-to-Q delay? That's usually the timing measurement designers are concerned with for flip flops.

 

[jayjavan2003]

I mean how to calculate hold time and d-q delay.

 

[shelby]

As gliss said, you may mean clk->q delay. There is no path from d->q in a flop. When a signal enters the d pin it stops inside the flop and does not come out the q pin until the next cycle.