max transition
kapil_vlsi1 said:
Yes, I am a Back-end Engineer but dont know how to fix transition time violations in Astro. Is it necessary to run CTO to fix transition time violations.
Hi. Dear kapil
The max transition time is one of the three Design Rules..(max fanout, max transition, max capacitance )
It is much more important than setup/hold timing.
As we all know, in STA , the delay of each std cell is calculated from looking up the NLDM ( non-linear delay model ) tables which is defined in library. These tables are two factors : input transition time, and output load. The result of table is the delay value of cell under certain input transition and output load.
If the input transition or output load is within but not the values in NDLM, interploation is utilized to calculate.
If the input transition or output load is out of range of NLDM, ext-interpolation is used to calculation. But it is natual the result would be rather in-accurate.
So the STA will be rather in-accurate. Timing analysis is un - believable .
Now. You can understand how important max tran is .