Solving Clock Signal Integrity and Jitter Issues

A recent blog post discussed the challenges of clock signal integrity and clock jitter in deep submicron semiconductor devices. Nice, clean clock signals are degraded due to many factors, including noise in the power delivery network (PDN). Timing variation due to clock jitter is also a serious issue, especially for chips operating at low voltage with high frequencies.

The impact due to clock jitter and compromised clock signal integrity can be severe, including metastability, races, long paths, and reduced maximum operating clock frequency (Fmax). Traditional simulations lack the subtle understanding of clocking requirements to detect all these issues before chips are fabricated. They run for days, or even weeks, and cannot handle the complete clock network of a large chip.

A dedicated clock analysis tool is the only solution. As discussed in detail in the previous post, such a solution must address four key failure mechanisms:

Clock Integrity:

• Rail-to-rail failures: Insufficient voltage swings leading to incorrect state retention
• Duty-cycle distortion: Imbalances in high and low clock pulse widths

Clock Jitter:

• Period jitter: The clock frequency does not meet its designed value
• Cycle-to-cycle: Each cycle may vary longer or shorter than the previous cycle

Tight integration with circuit simulation provides SPICE-level accuracy in a dedicated clock analysis solution. Scalable partitioning and distributed simulations deliver results in hours, not days or weeks. Tight integration with static timing analysis (STA) tools ensures more accurate timing results. Both tree and mesh clock networks can be analyzed, at the block, subsystem, and full-chip level. Analysis can be run on after clock tree synthesis and routing, or during the engineering change order (ECO) and signoff stages.

A recently introduced solution, Synopsys PrimeClock, meets all the requirements and addresses all the challenges outlined above and in the previous post. PrimeClock provides highly scalable and SPICE-accurate clock integrity and jitter analysis. It supports the analysis of both “fresh” and aging chips by modeling aging stress conditions. It enables full clock network analysis of individual clock domains and detailed path-based analysis of point-to-point paths. Turnaround time (TAT) is 100X to 1000X faster than general circuit simulation while maintaining SPICE-level accuracy.

PrimeClock can be invoked from an existing PrimeTime STA session. A pre-analysis option provides guidance to the user in choosing the optimal number of partitions for the specific clock network being analyzed.

PrimeClock checks for rail-to-rail (RTR) failures on full voltage swing for all clock pins in the clock tree, and duty-cycle distortion (DCD) for all pins in the clock tree. Users can generate reports as well as plots showing the results across levels of the clock network. When issues are found, users can also generate waveforms to help debug the source of the RTR or DCD violations.

PrimeClock is essential for high frequency designs greater than 1 GHz running at lower voltage. Typical applications that can benefit include AI, high performance computing (HPC), mobile devices, and advanced automotive electronics. These statements are based on actual customer experience, with some results that have been shared publicly. For example, Arm reported at the SNUG Silicon Valley 2025 event that they were able to analyze a 100M transistor design in only two hours, and that the clock integrity analysis identified structurally weak clock nodes that they were able to fix before release.

At the recent Synopsys Converge Conference 2026, Socionext presented a talk on their use of PrimeClock for timing closure: clock‑integrity analysis at SoC scale to achieve a 40% reduction in DCD runtime and faster convergence on a 3nm large‑scale AI/HPC design.

The benefits of dedicated clock integrity and jitter analysis are significant:

• Improved structural integrity of clock network
• Improved Fmax by reducing margins
• 100X  faster runtime compared to traditional simulation based analyses
• Up to 20X less compute usage for more efficiency

All developers of advanced chips need the Synopsys PrimeClock solution.