Setup Requirement Boundary Three-Row Scan - Electronic Circuits IV & XII: Digital Logic and Timing Closure Step by Step

The same arrival can pass, touch the edge, or fail as setup requirement grows.

The same arrival can pass, touch the edge, or fail as setup 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 setup rule leaves two seconds slack

Edge stays at 10 s and data stays at 7 s. Setup requirement 1 s gives setup slack 2 s, so the gate is pass.

s_{\text{setup}}=10\mathord{-}7\mathord{-}1=2\ \text{s}

Three-second setup rule lands on the boundary

Edge stays at 10 s and data stays at 7 s. Setup requirement 3 s gives setup slack 0 s, so the gate is pass.

s_{\text{setup}}=10\mathord{-}7\mathord{-}3=0\ \text{s}

Four-second setup rule rejects the same arrival

Edge stays at 10 s and data stays at 7 s. Setup requirement 4 s gives setup slack -1 s, so the gate is reject.

s_{\text{setup}}=10\mathord{-}7\mathord{-}4=\mathord{-}1\ \text{s}