Different gate delay in SoC Encounter and Primetime

Hi,

I observe difference delay value of a gate between SOC Encounter and Primetime as follows:

Timing report (post-route) in Encounter a specific path:

Timing report in Primetime of the same path:

What would be the reason of that or how could I debug the timing path (in both tools) to find the problem/reason?

Thank you.

When you debug timing between two tools, be sure, you have the same corner, the timing debate, the same sdc, report separately the cap from net and the cap from pin and the delay and transition. By this you will check also the parasitic impact and SI impact.
I will say first compare the timing report without SI, and the timing must be identical at the ps.
With SI, more difference could be observe.
Also check the parasitic factor, and if you have different spdef, used a tool like ostrich to compare both spdef.

Ideally you should not see any difference between 2 tools.

hairo said:

Hi,

I observe difference delay value of a gate between SOC Encounter and Primetime as follows:

Timing report (post-route) in Encounter a specific path:

Code:

/top/insta/xxx/yyy/U37/Y (NOR2XLTL)                                                                                                        0.217   (delay)           2.321 r (required time)

Timing report in Primetime of the same path:

Code:

/top/insta/xxx/yyy/U37/Y (NOR2XLTL)                                                                            2.90 (transition)      1.66 & (increment)     3.71 r (path)

What would be the reason of that or how could I debug the timing path (in both tools) to find the problem/reason?

Thank you.

Click to expand...

Transition in PT report is huge (2.9ns) . I dont see the transition time in Encounter reports. This can be the factor for the difference. Check why PT is seeing such a huge Transition time and you should find the answer.