D Latch (continued)

• Timing Constraints : To ensure that a specific value on excitation input D will determine the final state of the latch, D must not be allowed to change too near the time at which the enable signal makes its transition from high to low.

• Set up time: denoted tsu

is defined as the period of time immediately preceding the enable signal transition during which the excitation input must be stable.

• That is, the excitation input must be set up at least tsu prior to the enable signal transition and should not change until well after the transition.

Previous slide

Next slide

Back to first slide

View graphic version