Documentation

Technology - Layer Change Length

3 min read

The Layer Change Length is the additional length provided to a signal when going through a via or pad. By default, track lengths are calculated without taking any account of this additional length. These rules allow you to specify this. This rule can be used in conjunction with the Track Length Rules or Track Length Match Rules.

The general rule matching mechanism is described here.

Shortcuts

Menu: Setup

Default Keys: T

Command: Technology

Locating this option

Available from: Setup menu > Technology option > Rules - High Speed > Layer Change Length page

Using the Layer Change Length page

The buttons to the right side of the dialog are used to navigate the grid, the general common buttons are detailed on the Technology Navigation page.

Using the editing pane

The appropriate layer change rule is found for each net by working down the list of rules until the first match is found. Hence, the order of the rules is important. A match is when the specified Attribute Name and Match Value match an attribute of a net. So the net must have the given attribute, and it’s value must wildcard match the value. In particular, you can match the inbuilt attribute and . The first enclosing layer range is also matched. The From and To Layers are for the entry and exit layers of the track (which could be less than the span of the pad or via).

For a terminating pad, the length specified by this rule is the additional length to get the signal to the surface, so the From layer is the electrical layer on the side of the component (i.e. top or bottom electrical layer).

Applies To

The rule can apply to just Pads, just Vias or both.

Extra Track Length

The Extra Track Length is either calculated from the layer thicknesses, or can be specified as an explicit value by unchecking this option and typing the value required. If you have specified layers thicknesses, you are likely to want to use these.

Pin Package Length Attribute

Using the in-built attribute, you can define an internal length for the device. This attribute is added to one pin on a component with the value representing the internal connectivity length from the board surface through the package, for example 2.5mm. This will be in addition to any layer change value.

Export and Import CSV

Use the Export CSV button to export the data in your PCB design into a CSV format file. Using the Export CSV option will provide you with a formatted template ready for you to edit in your own data.

Use the Import CSV button to import data back into the PCB design using a CSV format file.

The data in the file represents a spreadsheet of dialog contents with the data headings along the top row.

Units

The Units button allows you to locally switch between Metric and Imperial units whilst in this dialog. Once the dialog is closed, the units revert back to the original design units. If switching to different units to the design units, the value typed will be converted when you next enter this page.

Technology Overview | Using Dialog Grids | Track Length Rules | Track Length Match Rules | Technology - Layers | Technology - Layer Spans | Design Rule Check | Export CSV | Import CSV

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