Signal Integrity - Impedance

This document is no longer available beyond version 4. Information can now be found here: Impedance Rule for version 5

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Rule category: Signal Integrity

Rule classification: Unary

Summary

This rule specifies the minimum and maximum net impedance allowed. Net impedance is a function of the conductor geometry and conductivity, the surrounding dielectric material (the board base material, multi-layer insulation, solder mask, etc) and the physical geometry of the board (distance to other conductors in the z-plane).

All design rules are created and managed within the PCB Rules and Constraints Editor dialog. For a high-level view of working with the design rules system, see Defining, Scoping & Managing PCB Design Rules.

Constraints

Default constraints for the Impedance rule.Default constraints for the Impedance rule.

  • Minimum (Ohms) - the value for the minimum permissible net impedance.
  • Maximum (Ohms) - the value for the maximum permissible net impedance.

How Duplicate Rule Contentions are Resolved

All rules are resolved by the priority setting. The system goes through the rules from highest to lowest priority and picks the first one whose scope expression matches the object(s) being checked.

Rule Application

Batch DRC and during Signal Integrity analysis.

Content