Introduction

The surest recipe for disaster is to give your schematic to a typical CAD person and walk away to "do more important tasks." Nothing is more important than PCB layout. It is the bridge, the only bridge, connecting your wonderful Mathcad-verified, Spice-validated, IEEE-published, Patent pending paper design, and a trouble-free finished product. So just make sure it is not a Half-Bridge you're unintentionally making!

You know by now that schematics lie. So how could a typical CAD person know how to interpret your schematic correctly? He or she could end up laying out a Buck just the same way as a Boost or a Buck-Boost. What's the difference, huh? The truth is every topology is quite different in terms of its recommended layout. So, when I take a look at a troubled Buck converter, I first look for assurance about something very specific in its layout. When I look at another topology, there is something else that quickly tells me what could possibly be wrong with it, in terms of its layout. These are the type of things I will try to clarify here. But there is a something else to talk about before we get there the concept of eval boards!

Evaluation Boards (EVBs)

In every semiconductor company I have worked in, we have been arguing about this since time immemorial. As of last notice, no one has yet figured it out completely. The discussion goes typically as follows (just hang in there). Should we make an...