Clock Domain Crossing Tools – Reviews & Metrics

Clock domain crossing sign-off tools perform structural and functional analysis to ensure that signals crossing asynchronous clock domains are received reliably. This article captures clock domain crossing reviews by users for the industry’s most popular clock domain crossing tools.

What is Clock Domain Crossing?

A clock domain crossing is when data is transferred from a flop driven by one clock domain to a flop driven by another clock domain. Because different clock domains don’t have a defined phase relationship, there can be problems transferring data from the source clock to the destination clock.

What is CDC Metastability?

Signal metastability can occur when a signal crossing from one clock domain to another clock domain and arrives too close to the receiving clock edge. Since the CDC signal can fluctuate, This can potentially cause illegal signal values to propagate through the design.

Clock Domain Crossing Tools

Clock Domain Crossing

What is CDC Sign Off?

Clock domain crossing sign off requires analysis, debug, modifications and verification that the data is properly transferred across clock domains, without introducing design problems.

Clock Domain Crossing Reviews

There are multiple commercial tools that will address CDC analysis and verification throughout the design process. Below are detailed user reviews on the most commonly used clock domain crossing tools from annual EDA user reports.

The dates are based on the year the reviews were published. For example the 2019 report was published in 2020.

The clock domain crossing reviews include: Real Intent Meridian CDC & Synopsys SpyGlass CDC.

Clock Domain Crossing Tool Metrics

Below are the primary metrics and criteria that the system and semiconductor design & verification engineers referenced when reviewing the products.

CDC Tool Metrics Covered

  • Sign-off methodology customizability
  • Noise level in CDC violation reporting
  • Debug usability, visibility and  drilldown
  • Performance & Capacity
  • CDC analysis depth
  • Set up time
  • Dynamic CDC Verification

Multimode CDC Tool Metrics Covered

  • Sign-off quality, including fit with STA sign-off
  • Low noise
  • Common report with no duplicates to save CDC violation debug time
  • Modeling & constraining the design for complex clocking structures
  • Set up time & Capacity