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Cadence PCB Design Blogs:RF PCB and Layou


Cadence PCB Design Blogs

Cadence PCB Design Blogs


What's Good About RF PCB and Layout? 16.6 Has Many New Enhancements!

Posted: 11 Dec 2012 09:31 AM PST

The 16.6 Allegro RF PCB application has many new enhancements. I'll cover a few over the next several weeks. Here are some major layout related enhancements:

  • Snap Enhancements
  • Add Connect Enhancements
  • Modify Connectivity Enhancements
  • Add Component Enhancements
  • Scaled Copy Enhancements
  • Single Segment Connection
  • Route with Any Angle Bend

Read on for more details …


Snap Enhancements

In Allegro 16.5, when you snap an RF component to a non-RF component pad, you can only snap to the connecting point (usually it is the center of the pad). Sometimes designers want to connect RF components with non-RF components at the edge of a pad. You can use this functionality to snap an RF component to a non-RF component, or a non-RF component to an RF component or even a non-RF component to another non-RF component based on the connectivity.

There is a "Snap to pad edge" check box on the form which is used for snapping to a specific edge of a pad:



Notice: When you snap a non-RF pad edge to another non-RF pad edge, this may result in violations for manufacturing/assembly, so you've to manually check all those violations.

The other enhancement for snap is that you can select some components as a temp group to snap together. During the snap command, RMB select Temp Group and then click a pin to snap, the whole temp group will be moved together.

The use model for the snapping pad edge is a little different from the original snapping functionality; once the "Snap to pad edge" option is checked, the Direction for "Fix source component" or "Fix destination component" will be disabled. The source component will be attached to your mouse and you need to move your mouse close to the destination component pad edge.

Add Connect Enhancements

The Add Connect command is enhanced to support snapping to pad edge functionality. When you check the "Snap to pad edge" option (this option is available once you check the "Snap to connect point" option), you can start routing from any edge of a pad by moving your mouse close the edge of the pad and clicking it to start.

There is another option named "Variable line width". This option will be available if the "Snap to connect point" option is checked. If you check the "Variable line width" option, the width of the RF trace will be variable based on the entry and the size of the pad and you can't change the trace width during the routing. If you uncheck this option, the width of the trace will use the value that you entered on the Options tab and you can change the width during the routing process.

There is an extra item on the RMB menu during the routing. It's "Accurate length". If you select it, a form will pop up and you can enter a specific value for the length that you want to route.

You can route RF trace with any angle mitered bend by setting as following:


 

Modify Connectivity Enhancements

This command is enhanced by adding a "Snap to pad edge" option. If this option is checked, the following "Fix source component" and "Fix destination component" options will be disabled:

Add Component Enhancements

The Add Component is enhanced with the new option of "Snap to pad edge". If this option is checked, the component to be placed can be located at a specific edge of a pad during the placement.



 
Scaled Copy Enhancements

This command is enhanced by increasing the option "Snap to pad edge". Once this option is checked, the scaled copied RF component can be connected to any edge of a pad.


 

Single Segment Connection

In some cases, designers may want to connect two points (pads) with a single segment (microstrip line for example). You can use this new command by clicking RF-PCB->Single Segment Connect as below:


 

Route with Any Angle Bend

This is a new command to connect two pins/pads with any angle mitered bend. We're trying to use three RF components (two line segments and one any angle mitered bend) to connect two specific pins/pads. The line segment may be Microstrip Line (MLIN) or Stripline (SLIN) and the any angle bend may be MBEND or SBEND2. Click RF-PCB->Any Angle Bend Connect to launch this command.
 

The parameters are shown on the Options tab as shown below:



 
If you have anything to share on how you're using these new features – please do!

Jerry "GenPart" Grzenia


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