Allegro PCB Design Tutorial

Connect Pin and Mechanical Pin

Allegro provides two types of pins - Connect Pin and Mechanical Pins. As the name implies, the Connect Pins are usually the electrical pins that connect to something. When you create a symbol, all the pins that are required electrically should be Connect Pins. This includes any pins that are required to be connected to Ground. For Example if there is a Center thermal pad in a footprint, it should be a connect pin. All connect pins should be shown as a unique Pin with a unique Pin number in OrCad Schematics.

Mechanical pins do not connect electrically to anything. There are two ways to deal with it. It is possible to use a mechanical pin as a Connect Pin. There is actually no harm in it. However, you will have to declare these pins as some pin number in the Schematics. The Schematics designer usually do not bother to include these pins in their schematics. If you are doing the Schematics as well as Layout, you can just add the mechanical pin as an electrical pin in the Schematics and you should be good to go. If you are working in a team, however, the better option will be to develop the symbol of the non electrical pins as mechanical pins. This also keeps the Schematics clean, showing only the required electrical pins.

You may also change and electrical pin to a mechanical pin by just selecting the text of the Pin number and , deleting it. This needs to be done inside the Allegro Symbol.