Thermal modeling heats up for the MAINSTREAM

摘要

Getting The Heat out of systems is one of the oldest challenges of electronics design. It's also the aspect that potentially affects reliability the most: Conventional wisdom suggests that every 10℃ increase in junction temperature approximately doubles a semiconductor device's failure rate. The devices that require thermal attention are no longer limited to power supplies; discrete components, drivers, processors, and even random logic functions now come in packaging densities that force system-level consideration. This trend is proliferating, with many vendors introducing proprietary packages, typically variations on surface-mount designs for power semiconductors. Recent examples include International Rectifier's DirectFET devices; National Semiconductor's LLP (leadless low-profile) chip-scale and micro-SMD packages; and the LFPak (loss-free package) from Philips. Seemingly, the drive for ever-lower on-resistance in power FETs has reached a plateau, and the new amps-per-square-inch constraint is package dissipation.