KEY Routing is timing-driven and needs the clock built first; routing first starves the clock tree of resources and worsens skew.

Poor Clock Transition - Power and Timing

• Dynamic power rises because short-circuit power increases with a slow clock edge.
• Clock cell delays increase, and the timing impact depends on where that cell sits in the clock network.
• Overall design performance suffers - the achievable operating frequency comes down.
• If the transition is poor on the CK pin of a capture register, the library setup and hold times grow, making setup and hold fixing more complex.

KEY A poor clock transition raises short-circuit power and cell delay, hurts frequency and worsens library setup/hold.

Clock Mesh vs Regular CTS

A clock mesh gives better skew, lower latency, and supports higher performance or frequency, which makes timing closure easier.

KEY A clock mesh delivers better skew, lower latency and easier high-frequency closure than regular CTS.

Placing Clock Gates - Sink or Root

• For timing, placing the integrated clock gate (ICG) near the sinks is better because it helps meet the ICG enable timing - but power is worse.
• For power efficiency, placing the ICG near the root gives better power reduction - but the enable-pin timing is worse.

KEY ICG near sinks favors enable timing; ICG near the root favors power.