Align

1Introduction

Align is a background automation tool for Mentor Xpedition PCB that precisely positions components, vias, and via arrays on a printed-circuit-board layout. Rather than requiring the designer to manually nudge objects into place, Align reads whatever is currently selected on the board, determines the correct geometry, and moves the objects into their optimal positions in a single step — all while respecting the design rules already defined in the project.

The tool is designed for PCB layout engineers who regularly place bypass capacitors, series resistors, or differential-pair vias next to multi-pin ICs. It eliminates tedious manual positioning work and ensures that component placement is geometrically precise and DRC-clean every time.

Align has no configuration window to fill in. Everything is driven entirely by what you select in Xpedition before you run the tool. When launched, a small status window may appear momentarily — this is normal, and it closes on its own once the operation is complete.

2Requirements and Setup

• Mentor Xpedition PCB must be installed, licensed, and have a PCB document open and active.
• An ExactCAD license file must be present. The file is named Exactcad_License.txt and must be located in the ExactCAD folder inside your Windows local application data directory (typically C:\Users\YourName\AppData\Local\ExactCAD\).
• Your ExactCAD license must include the Align feature. If it does not, a licensing error will appear when you launch the tool.
• The tool executable (align_v1.01.exe) should be placed in a stable folder on your system. Many users add it as a custom command in Xpedition so it can be launched directly from the toolbar.

3How the Tool Works

Align is entirely context-driven. Before running the tool, you select pins, vias, or mounting holes directly on the Xpedition board canvas. The tool inspects the selection, identifies the scenario, and automatically applies the correct alignment logic. You do not choose a mode or fill in any settings — the selection itself is the instruction.

The table below summarises every selection pattern the tool recognises and what it does in each case:

4Alignment Scenarios in Detail

Each sub-section below describes one specific use case, explains when to use it, and walks through the exact steps to follow.

4.1 Aligning Two Components Pin-to-Pin

Use this when you have two components that face each other — for example, a resistor next to an IC — and you want one specific pin on each part to be perfectly in line.

1. In Xpedition, select exactly one pin from the first component and one pin from the second component. Both pins must belong to different parts.
2. Run the Align tool.
3. The tool automatically determines which component has fewer pins and moves that one (unless it is locked, in which case the other one moves). The component is shifted only along the axis that is perpendicular to the direction the parts face each other — it will not drift toward or away from the reference component.

Before and after: the resistor's selected pin is moved into alignment with the IC's pin.

4.2 Placing Small Components Between Two Reference Pins

Use this to place one or two small components — such as a pair of bypass capacitors or a pair of series resistors — symmetrically between two specific pins on a larger IC or connector.

1. In Xpedition, select exactly two pins on the larger reference component and one pin each on one or two small components. The total selection is either three or four pins.
2. Run the Align tool.
3. The tool calculates the midpoint between the two reference pins, then moves the small component or components so they sit centred and symmetrically on the side of the large part nearest to where the small parts already are. If two small parts are selected, they are positioned symmetrically on either side of that midpoint, maintaining the spacing between them.

Two small components placed symmetrically between two reference pins (series configuration).

Single small component centred between two reference pins (parallel configuration).

4.3 Aligning Vias to Component Pins

Use this to snap vias into the correct position relative to a component's pins — for example, placing breakout vias directly off of a differential pair of IC pins.

One pin, one via:

1. Select one pin on a component and one via.
2. Run the Align tool.
3. The via moves to align with the selected pin. The tool calculates the angle from the pin to the via's current position and rounds it to the nearest 45°, then repositions the via at the same distance along that rounded angle. The via ends up neatly on-grid and pointing in a clean 45° direction from the pin.

Before and after: the via snaps to the nearest 45° angle from the selected pin.

Two pins and two vias (differential pair):

1. Select two pins on a single component (typically a differential pair) and two vias.
2. Run the Align tool.
3. The tool positions the two vias symmetrically, perpendicular to the midpoint of the line between the two pins, at the minimum allowed via-to-via spacing for the current net class, snapped to the nearest 45° angle. Interactive DRC is temporarily suspended during the move to prevent false errors, then re-enabled when the move is complete.

Before and after: two vias repositioned symmetrically off a differential pair of IC pins.

4.4 Spacing Vias at Minimum DRC Clearance

Use this when you have a group of vias that need to be evenly spaced at the minimum allowed distance from each other — for example, a breakout fan-out from a BGA component.

1. Lock exactly one via in Xpedition to act as the anchor point. This is done using Xpedition's standard lock/anchor command on that via.
2. Select the locked via along with all the other vias you want to position.
3. Run the Align tool.
4. The locked via stays in place. Each unlocked via is moved to the minimum-clearance spacing from the locked via, in the direction it was already heading (angle rounded to the nearest 45°). If several unlocked vias are selected, they are all snapped to the same locked anchor in sequence.

Before and after: unlocked vias snapped to minimum clearance spacing from the locked anchor via.

4.5 Filling a Pad with Vias

Use this to flood a large pad with as many vias as will fit — common for thermal relief pads on power components or large ground pads that need maximum copper connection through to inner layers.

1. Select the pin (pad) you want to fill.
2. Run the Align tool.
3. The tool calculates how many vias fit within the pad boundary in a uniform grid, using the net class default via padstack and the minimum DRC via-to-via spacing. It then places vias at every valid grid point that falls inside the pad boundary.

4.6 Placing Vias Around Mounting Holes

Use this to automatically ring a mounting hole with vias — useful for stitching the ground plane around a mechanical fastener point.

1. Select one or more mounting holes on the board.
2. Run the Align tool.
3. For each selected mounting hole, the tool places vias at eight positions around the hole (every 45°), using the net class default via padstack. The vias are placed at a distance that takes both the hole size and the via size into account so they sit just outside the annular ring.

5Typical Workflow

The following steps describe a common day-to-day use of Align for placing bypass capacitors next to an IC:

1. Open your PCB design in Mentor Xpedition and place the bypass capacitors in the rough area where you want them — they do not need to be precisely positioned yet.
2. Zoom in on the IC and identify the two power or signal pins the capacitors are meant to bypass.
3. Using Xpedition's selection tools, click to select those two pins on the IC, then add the corresponding pin from each capacitor to the selection. You should have four pins selected in total.
4. Launch the Align tool from your toolbar, menu, or by running the executable directly.
5. A small window may flash briefly on screen — this is normal. The tool runs and closes automatically.
6. The capacitors will have been repositioned symmetrically between the two reference pins, centred on the IC's pin pitch.
7. If the result is not what you expected, press Ctrl+Z in Xpedition to undo the move and try again with a different selection.

6Tips & Troubleshooting

• Nothing moved after running the tool. Make sure something is actually selected in Xpedition before launching. Align reads the live selection — if nothing is selected, the tool closes without doing anything.
• Licensing error on startup. Verify that Exactcad_License.txt is present in C:\Users\YourName\AppData\Local\ExactCAD\ and that the license code inside it is valid and includes the Align feature. Contact ExactCAD support if you need a replacement license.
• The tool says it cannot connect to Xpedition. Make sure Xpedition is running and has a PCB document open. If multiple Xpedition sessions are open, close the extra ones and try again.
• A component that I did not want to move was moved. The tool moves the component with fewer pins unless it is locked. If you want a specific component to remain fixed, lock it in Xpedition before running Align. Use Undo (Ctrl+Z) to recover from any unintended moves.
• The via ended up at the wrong angle. The tool rounds all angles to the nearest 45°. If the via was at a very unusual angle to the reference pin, it may have snapped to a direction you did not expect. Use Undo, reposition the via slightly closer to the intended direction, then run the tool again.
• DRC violation error when aligning vias. Occasionally the design rules prevent a via from landing in the calculated position. Use Undo, adjust the approximate position of the via slightly, and try again.
• The pad fill placed too few vias or none at all. This usually means the pad is small relative to the default via size for that net class. Check the net class via padstack setting in Xpedition's design rules and confirm that the pad and via sizes are compatible.