# Single-ended Impedance Control

This constraint enables impedance-controlled routing for RF nets and other fast, long, or sensitive traces. 

### Automatic Detection

* Currently, single-ended impedance nets can only be entered manually.

### Constraint details

<figure><img src="https://1761213452-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FL9R6Vsa5jGn27oTws0tG%2Fuploads%2FRq5nheUHOUZSiQb6rbuq%2FScreenshot%202025-06-05%20at%209.51.04%E2%80%AFAM.png?alt=media&#x26;token=8e1c751a-baf1-4808-bce8-11c1daf86a52" alt=""><figcaption></figcaption></figure>

Single-ended impedance control can be applied to nets in the "Single Ended Impedance Signals" section of Circuit Comprehension. You can add them one at a time, match them using regex, or apply a netclass. &#x20;

To define a high current net constraint, you need to fill in the following fields: &#x20;

1. Net name &#x20;
2. Target impedance (we currently support 50Ω and 75Ω) &#x20;
3. Signal frequency (GHz) &#x20;

Quilter will automatically perform the impedance control calculations that take into account the specified stack-up's material properties to determine the correct trace width necessary to achieve the specified impedance within a tolerance of 5%.

### Physics Rule Checks

The following PRCs validate this constraint after compilation:

**Invalid Width Span** determines the length of trace paths in a net are outside of an acceptable tolerance threshold. A trace segment has an “invalid width” if its width is outside of a 10% tolerance when compared to the nominal value.

**Ground Plane Overlap** determines if the ground plane below net traces overlaps at all relevant points.