In PT, the set_operating_conditions cmd specifies the operating conditions for analysis, so that PT can use the appropriate set of the parameter valus in the technology library.
PT offers 3 analysis modes with respect to operating conditions, called the single, best-case/worst-case, and OCV modes.
In the single operating condition mode, PT uses a single set of delay paramaters for the wole circuit, based on one set of process, temperature, and voltage conditions.
In the best-case/worst-case mode, PT simultaneously checks the circuit for the two extreme operating conditions, minimium and maximum.
For setup checks, it uses maximum delays for all paths. For hold checks, is uses minimum delays for all paths. This mode lets you check both extremes in a single snalysis run, thereby reducing overall runtine for a full analysis.
In the OCV mode, PT performs a consevative analysis that allows both minimum and maximum delays to apply to different paths at the same time. For a setup check, it uses maximum delays for the data path and minimum delays for the clock path. For the hold check, it uses minimum delays for the data path and maximum delays for the clock path.
An optional analysis technique called clock recovergence pessimism (CPPR) increases the accuracy of OCV analysis by ensuring that each individual circuit element effectively uses either the minimum or maximum delay, but not both, for any given setup or hold check.
why it will add only max delay for data path in setup chk??
ReplyDelete