Setup and Hold violation on the D pin of a flipflop

[enishank]

If i have setup and hold violation on a D pin of a flipflop. What can be the reason and how to solve it.

 

[phoenixpavan]

Hi enishank,

Please search through the forum...there are lot of good threads over setup and hold times..like https://www.edaboard.com/threads/208395/#post879975 and so on

cheers,

 

[vani123]

Hi enishank,

Phoenixpavan is right.. even I am new in this forum but there is lot in this forum for setup and hold time. you can check few more bolgs also.

"Setup and Hold Time" : Static Timing Analysis (STA) basic (Part 3a) |VLSI Concepts

Setup time, Hold time

 

[conn2raje]

Hi.,

Setup and hold time violations are due to delays in the flip-flop.

To overcome these delays,
Add some buffers between them to meet delays.

 

[enishank]

Thanks for the pointers and sorry if my question was not clear, i was not asking the fixes for general scenarios. my Question was that can we have setup and hold violation (both) on a single D pin of a flop at the same time.. Then how to solve it.

 

[FvM]

my Question was that can we have setup and hold violation (both) on a single D pin of a flop at the same time..

Yes, there are several ways to get it
- too much delay skew
- the input signal is too fast (not stable for a sufficient long amount of time) respectively the D-FF too slow

Then how to solve it.

Sounds like you are asking to retell one or more textbook chapters. In general, try to change the conditions causing timing violations.

 

[shelby]

fix the setup violation, then buffer the hold violation at the Q pin of the launching flop with the hold violation (or at least somewhere on the path not common to the setup violation)

This is assuming the violations are not from the same launching flops.