1 Introduction

There have been significant advancements in semiconductor packaging in the last two decades, especially with DC/DC converters that integrate power metal-oxide semiconductor field-effect transistors (MOSFETs). Through-hole and leaded packages have been replaced with single-outline no-lead and quad flat no-lead (QFN) packages capable of handling high output currents in very small form factors. Smaller semiconductor packages often pose design and layout challenges that new packaging technologies can help resolve, and new QFN packaging technology is available for DC/DC converters with improvements over traditional wire-bond and flip-chip QFN packages. Unfortunately, DC/DC converters deliver and dissipate significant heat and are subject to package and circuit board parasitic effects, and comparing one package technology to another is often inconclusive since the die are different.

In this article, we will take a look at two point-of-load DC/DC converters, providing up to 20 A with the same die, to directly compare a traditional flip-chip HotRod™ package and the new flip-chip Enhanced HotRod™ QFN package, demonstrating thermal, switch-node ringing, transient, efficiency and layout differences to help you decide if the Enhanced HotRod QFN package is more advantageous for your application, and if it can help improve power-supply density and performance enough to overcome any potential skepticism around adopting new technology.