21/08/2025

How do you fix crosstalk violations? Why Downsize the Aggressor Driver?

1.       Increase Spacing: Physically increase the distance between the victim and aggressor nets during routing. This directly reduces coupling capacitance (Cc​). (Most effective but consumes routing area).

2.       Shielding: Insert a static net (tied to VDD or VSS) between the victim and aggressor. The shield net intercepts coupling capacitance, preventing interference. This can add coupling cap on signal net causing delay.

3.       Layer Change: Route the victim or aggressor on different metal layers for a portion of their length to reduce parallel run length and coupling.

4.       Buffer Insertion (on Victim): Inserting a buffer breaks the victim net into smaller segments, potentially reducing the total coupled capacitance

5.       Driver Sizing (Victim Upsizing): Increase the drive strength of the cell driving the victim net. A stronger driver can overcome the noise injection or delta delay effect more easily

6.       Driver Sizing (Aggressor Downsizing): Decrease the drive strength of the cell driving the aggressor net. A weaker aggressor has slower transition times (dV/dt), which reduces the amount of noise current injected into the victim via the coupling capacitance

7.       Timing Window Adjustment (Useful Skew): Slightly shift the timing of the victim or aggressor (if possible without causing other violations) so their switching windows no longer overlap significantly, reducing the delta delay impact.

 

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