ST Micro's LFPAK series SMD Mosfets

摘要

Mosfet Q1 is an ST Micro part with an incredibly low on-resistance - barely more than 1 milliohm. It is rated to carry 100A but it will dissipate around 1W at 30A (I~2 × R) so without heatsinking (other than the PCB), it won't handle much more than that. Its on-resistance is so low that losses in the Mosfet itself are a minor component of the dissipation, most of it being in the PCB and wiring. This is only really possible with SMDs since a TO-220 through-hole package has 1m Ωof resistance in the package/ leads alone.