Pulse Width Checks - 2025.2 English - UG906

Vivado Design Suite User Guide: Design Analysis and Closure Techniques (UG906)

Document ID
UG906
Release Date
2025-12-10
Version
2025.2 English

Pulse width checks are rule checks on signal waveforms as they reach hardware primitives after propagating through the device. These checks usually reflect functional limits set by the internal circuitry of the primitive. For example, the minimum period check on a DSP clock pin ensures that the clock driving a DSP instance doesn’t exceed the maximum frequency tolerated by the DSP.

Pulse width checks do not affect synthesis or implementation. Their analysis must be performed at least one time before generating the bitstream like any other design rule check in the Vivado Design Suite.

A pulse width violation usually comes from an incorrect clock definition, failing pulse width or period checks. It can also result from excessive skew in the clock topology, failing max_skew. Review the AMD FPGA data sheet for your target device to understand the valid operating range for the primitive where the violation happens.

If the violation is due to skew, simplify the clock tree or place clock resources closer to the affected pins to reduce the skew.