First things first - Getting your PCB layout off to a good start

We've all been there, or we will be someday. A new concept has emerged, and the team is given a chance to own that niche. To save time, we're going to leverage an existing design. Yes, the good old “design reuse” scenario.

Overcrowding aside, dropping a new or revised circuit into a preset form factor will occasionally be more effort than building a new chassis around the electronics. Compare it to building a new house out in the country vs. rehabilitating an old one in town. 

Let us walk through a situation where part of a device has to be moved for reuse in another design. The image below shows the device we want to ‘cut’. Everything inside the phantom line must go! That would be the BGA device, the 2-pin component right above it and the column of parts to the left-hand side.

The tough part is that there is a mass of connections, as shown in the image below.

The upside is that you can take them one layer at a time and remove all the trace segments that cross the imaginary line. Or, you can preview each layer and then take your segments out in four easy cuts around the perimeter.

A good start does not guarantee a good finish, but a poor start doesn’t have a chance. Click here to go through some of the key points like placement, routing, stackup verification, and recalibrating the design rules, which can help you in a good start.

Team PCBTech

Cadence Design Systems