Module 32 min

Setup & Hold Slack Analysis

Data arrives before required time. Extra margin available. Setup: Slack = +0.3ns means 300ps of timing margin. Design passes. No action needed.

Setup Slack

Slack_setup = (T_clock – T_setup – T_cq_launch – T_combo) – T_arrival

Setup Required Time

T_required = T_clock_edge + T_clk_latency_capture – T_clock_uncertainty_setup – T_setup

Hold Slack

Slack_hold = T_arrival – (T_clk_latency_capture + T_hold)

Data arrives before required time. Extra margin available. Setup: Slack = +0.3ns means 300ps of timing margin. Design passes. No action needed.

slack: +0.350 ns (MET)

Negative Slack (VIOLATED)

Data arrives AFTER required time. Setup violation = data might not be captured correctly. Must fix before tape-out. Hold violation = data changes too fast.

slack: -0.120 ns (VIOLATED)

Sample Timing Report (PrimeTime Format)

TIMING REPORT - Setup Analysis

===========================================================
Path Type       : max (Setup)
Point                              Incr       Path
===========================================================
--- Input Port ---
clock CLK (rise edge)              0.000      0.000
clock network delay (ideal)         0.500      0.500
FF1/CK                              0.000      0.500 r
--- Data Path (Launch) ---
FF1/Q       (DFF_X2/Q)               0.120      0.620 r
U101/Y      (AND2_X4/Y)              0.085      0.705 r
U102/Y      (OAI21_X2/Y)             0.110      0.815 f
U103/Y      (INV_X4/Y)               0.062      0.877 r
U104/Y      (BUF_X8/Y)               0.075      0.952 r
FF2/D                                0.000      0.952 r
data arrival time                                0.952
--- Capture Edge ---
clock CLK (rise edge)              5.000      5.000
clock network delay (propagated)    0.510      5.510
FF2/CK                              0.000      5.510 r
library setup time                 -0.085     5.425
data required time                               5.425
-----------------------------------------------------------
data required time                               5.425
data arrival time                               -0.952
-----------------------------------------------------------
slack (MET)                                       4.473
===========================================================

Interactive Waveform Lab

Toggle signals, animate the timeline, and inject a setup or hold violation to see exactly how it appears on a real CLK / D / Q waveform.

■ CLK — System Clock■ D — Data Input■ Q — FF Output■ RESET — Async Reset