Hold Requirement Boundary Three-Row Scan - Electronic Circuits XII: Clocks, Latches, and Timing Closure Step by Step

The same next-change time can pass, touch the edge, or fail as hold requirement grows. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

One-second hold rule leaves one second slack

Edge stays at 10 s and next change stays at 12 s. Hold requirement 1 s gives hold slack 1 s, so the gate is pass.

s_{\text{hold}}=12\mathord{-}10\mathord{-}1=1\ \text{s}

Two-second hold rule lands on the boundary

Edge stays at 10 s and next change stays at 12 s. Hold requirement 2 s gives hold slack 0 s, so the gate is pass.

s_{\text{hold}}=12\mathord{-}10\mathord{-}2=0\ \text{s}

Three-second hold rule rejects the same next change

Edge stays at 10 s and next change stays at 12 s. Hold requirement 3 s gives hold slack -1 s, so the gate is reject.

s_{\text{hold}}=12\mathord{-}10\mathord{-}3=\mathord{-}1\ \text{s}