PCB_Cmd-PlaceViaPlaceVia_AD

Applied Parameters: None

Summary

This command is used to place a Via object onto the active document. A via is a primitive design object. It is used to form a vertical electrical connection between two or more electrical layers of a PCB. A via is a 3-dimensional object, having a barrel-shaped body in the Z-plane (vertical), with a flat ring on each (horizontal) copper layer. The barrel-shaped body of the via is formed when the board is drilled and through-plated during fabrication. In the X and Y planes, vias are circular, like round pads. The key difference between a via and a pad is that as well as being able to span all layers of the board (top to bottom), a via can also span from a surface layer to an internal layer, or between two internal layers.

Access

Vias are available for placement in both PCB and PCB Library Editors:

• PCB Editor - the following methods of access are available:
  • Choose Place » Via from the main menus.
  • Click the  button on the Wiring toolbar.
• PCB Library Editor - the following methods of access are available:
  • Choose Place » Via from the main menus.
  • Click the  button on the PCB Lib Placement toolbar.
  • Right-click in the workspace and select Place » Via from the context menu.

Use

After launching the command, the cursor will change to a cross-hair and you will enter via placement mode. A via will appear "floating" on the cursor:

1. Position the cursor and click or press Enter to place a via.
2. Press the Tab key to access the Via dialog, from where properties for the via can be changed on-the-fly.
3. Continue placing further vias, or right-click or press Esc to exit placement mode.

Tips

1. Vias can be multi-layer (passing from the Top layer to the Bottom layer through all other layers) or confined to any two signal layers - known as blind or buried vias. A blind via connects from the surface of the board to an internal signal layer, a buried via connects from one internal signal layer to another internal signal layer. Vias use layer colors to indicate which layers are connecting.
2. If blind, buried or build-up type vias are to be used, the Drill pairs must be configured, with a drill pair for each layer-pair that a via spans. Consult your board fabricator if you are designing a multi-layer board that is going to include blind or buried vias, to ensure the optimal layer stack up and layer-pairing are achieved.
3. A via will adopt a net name if it is placed over an object that is already connected to a net.
4. Typically vias are not placed manually, they are placed automatically as part of the interactive routing process. When you change layers during manual, interactive routing, a via is automatically inserted to preserve the electrical conductivity.
5. A selected via template - in the PCB Pad Via Templates panel - can be reused in the current board as a new via instance by dragging it onto the layout, or by choosing Place from the panel's right-click context menu.
6. A via template that is stored as part of a Pad Via Library can also be placed in the PCB design, directly from the PCB panel, when configured in Pad & Via Templates mode. Simply choose the required template library, then select the required via template within that library and click the Place button (in the Templates region of the panel).