1Introduction
Exit 45 is a routing aid for differential pairs in Xpedition. With a single keystroke, it draws a clean, symmetric pair of escape traces that leave two vias or two pins at exactly 45 degrees, then bends them inward until they sit at the proper differential-pair spacing, ready for you to continue routing.
Because a differential pair is always two nets travelling together, Exit 45 always works on two conductors at once. It places both escape traces in one operation, mirrored about the centerline between the two starting points, so the pair stays balanced and length-matched as it leaves the breakout.
The tool has no window or dialog of its own. You select the objects you want to escape from, press the assigned hotkey, and the traces appear. Everything you need to control happens through what you select and how your design is set up.
2Requirements & Setup
Before you run Exit 45, make sure the following are in place:
- Xpedition is open with a design loaded. Exit 45 attaches to your running Xpedition session and acts on the active design.
- A licensed copy of Exit 45. The tool must be installed and licensed through your ExactCAD license. See the Install Instructions for installation and the Hotkeys guide for assigning the keystroke that launches it.
- The two nets are a defined differential pair. When you escape from pins, the tool finds the partner conductor through the differential-pair relationship, so that pairing must already exist.
- An active routing layer is set. The escape traces are placed on whatever layer is currently active for routing.
- Trace width and pair spacing are defined for that layer. Exit 45 reads the typical trace width and the differential-pair spacing from your net-class settings for the active routing layer, so those values should be set up the way you want them routed.
- There is an unrouted connection to follow. The pair should still have an open connection (an unrouted netline) leading away from the vias or pins. Exit 45 uses the direction of that open connection to decide which way to send the traces.
3How It Works
When you run Exit 45, it looks at what you have selected, identifies the two conductors of the differential pair, and builds a matched pair of escape traces. Each trace leaves its starting point at a 45-degree angle, runs a short distance, and then turns to run straight at the target pair spacing. The two traces are mirror images of each other about the line connecting the two starting points, which keeps the pair symmetric and balanced.
3.1 Sensing the Exit Direction
Exit 45 has to decide which way to send the traces — left or right of the breakout. It does this by looking at the rest of the pair on the same nets and finding the nearest unrouted target: the closest open trace end, via, or pin that the pair still needs to reach. The direction toward that nearest open target tells the tool which side to escape toward, so the new traces head naturally toward the rest of the route instead of doubling back.
3.2 Trace Width & Spacing
The escape traces are not drawn at arbitrary dimensions. Exit 45 reads two values from your design constraints for the active routing layer and applies them automatically:
- Trace width — the typical trace width defined for the pair's net class on the active routing layer.
- Pair spacing — the differential-pair spacing defined for that same net class and layer. This is the spacing the two traces converge to once they finish their 45-degree exit.
The tool also makes sure each trace runs far enough past the via or pad before the first bend, so there is always a clean stub of trace leaving the object rather than a corner sitting right on top of the pad.
4What to Select
Everything Exit 45 does is driven by your selection. You can escape from a pair of vias or from pins. The tool decides what to do based on what is selected when you press the hotkey.
4.1 Exiting from Vias
To escape a pair from vias, select exactly two vias — one on each net of the differential pair — and run the tool. Exit 45 figures out their left/right or top/bottom arrangement on its own and builds the matched 45-degree exits between them.
4.2 Exiting from Pins
To escape a pair from component pins, select the pins of the differential pair and run the tool. You can work one pair at a time or several pairs at once:
- One pair: select the two pins that make up the differential pair.
- Several pairs at once: select all of the pins you want to break out. Exit 45 sorts them into differential pairs using the defined pair relationships and escapes each pair in turn, so you can break out a whole connector or device in one pass.
5The Two Versions: Standard and Anti
Exit 45 ships as two nearly identical tools. They behave exactly the same except for one thing: the direction the traces are sent.
| Version | Behavior |
|---|---|
| Standard Exit 45 | The everyday tool. It chooses the exit direction automatically by following the open connection on the pair, as described above. |
| Exit 45 Anti | Identical in every way, except it sends the traces in the opposite direction from what the standard tool would choose. Use it as the fix when the standard tool escapes the wrong way. |
Normally you use the standard tool. If the escape comes out heading the wrong direction for a particular breakout, undo it, select the same objects again, and run the anti version instead to flip it the other way.
6Typical Workflow
A normal differential-pair breakout with Exit 45 looks like this:
- Confirm your active routing layer and your differential-pair width and spacing constraints are set the way you want the pair routed.
- Select the two vias of the pair, or the pins of one or more pairs you want to break out.
- Press the Exit 45 hotkey. The matched 45-degree escape traces appear, converging to the pair spacing and heading toward the open connection.
- Check the result. If the traces escaped in the right direction, continue routing the pair as normal.
- If the escape went the wrong way, undo it, reselect the same objects, and run the anti version to send it the opposite direction.
7Tips & Troubleshooting
- The traces exited the wrong direction: Undo, reselect the same vias or pins, and run the anti version. It forces the opposite exit direction.
- The tool says exactly two vias must be selected: When escaping from vias, select precisely two — one per net. Deselect any extra vias and try again.
- Nothing happens, or you get a message about no netlines: Exit 45 follows an open connection to choose the direction. Make sure the pair still has an unrouted connection leading away from the breakout, then run it again.
- The width or spacing of the new traces looks wrong: Those values come from your net-class constraints for the active routing layer. Check the differential-pair width and spacing defined for that layer, then re-run.
- Pins are skipped when breaking out many at once: Only pins that belong to a defined differential pair are processed. Confirm each pin's pair relationship exists.
- The escape landed on the wrong layer: Traces are placed on the active routing layer. Set the layer you want active before running the tool.