Maximum Transition Violations

What is a transition time?

Transition time is the duration it takes for a signal to change from one logic level to another level. This can be further divided into:

• Rise Time(Tr): The time it takes for the signal to transition from a low voltage level(logic 0) to a high voltage level(logic 1).

• Fall Time(Tf): The time it takes for the signal to transition from a high voltage level(logic 1) to a low voltage level(logic 0).

What is slew?

A slew is defined as a rate of change. In STA analysis the rising or falling waveforms are measured in terms of whether the transition(slew) is fast or slow. Slew is measured in terms of transition time, i.e., the time it takes for a signal to transition between two specific levels(1 to 0 or 0 to 1).

Transition time is the inverse of slew rate.

• larger the transition time, the slower the slew

• smaller the transition time, the faster the slew