A Note on Exposed Pads

A project log for Blue Board #01

Prototyping Playground for SMD and TH Components

Alan GreenAlan Green 04/19/2019 at 23:160 Comments

Some dual inline package parts have an exposed pad, which is used as a heatsink for the part. This is particularly common for parts that drive large currents (example). However, because of the variety of widths parts come in, and how that means the pads have to be arranged,  I’ve chosen not to add an exposed pad to the footprints on BlueBoard#01.

There are several alternatives:

  1. Cover the exposed pad with kapton tape and solder it anyway. You won't get the same thermal performance, but it might be enough for your prototype.
  2. See if you can find an alternative footprint for the part that doesn't use and exposed pad. The LM25085, for example comes in several packages, one of which doesn't use an exposed pad.

Please let me know if you were unable to use BlueBoard#01 for your project because you needed to use a particular part with an exposed pad, but were unable to.