The IRF3708PBF has long been my go-to through-hole MOSFET - a beefy TO-220 FET, good to 30Vds, and can handle tens of amps with added cooling.... but the real magic was that it was rated for Vgs = 2.8V, meaning you could comfortably control it with a 3.3v device and count on Rds(on) of 29 milliohm (max, 15 typ) (and that's at 2.8v, so it would be even better). A perfect power MOSFET for 3.3v boards like Espruino.
Well, unfortunately, Infineon is shutting down the line they make them at, and discontinuing the product. Their recommended replacements don't switch at 3.3v, and there aren't any other beefy through-hole MOSFETs that switch at 3.3v... at all. In fact, there aren't even any easily-soldered (ex, DPAK) SMD power MOSFETs that switch at 3.3v and can handle more than 20v (though the MCC90N02, recently released, has specs to die for in DPAK, but 20Vds maximum), as the DPAK version is being discontinued too.
So, if you think you ever might want to switch a load too heavy for a SOT-23 FET (those cap out at ~6A, manufacturer-spec-numbers, which one should never expect to push to the max) with an Espruino, and don't want to commit to the expense and complexity of a gate driver, and don't have the means to solder weird parts like Power-TDSON-8, you should order some with a sense of urgency!
Yes, I am aware that $parkfun says that you can use an FQP30N06L with a 3.3v gate voltage. The performance curves in the datasheet say otherwise - at least for loads that couldn't be handled by the top-end, much smaller, SOT-23 fets...
Just thought I'd let y'all know the bad news over here, since I clearly remember talking about it here - I think it's even in the MOSFET guide in the docs, assuming it hasn't been edited.
© Espruino, powered by microcosm.
Report a problem