17mm & 20/26/27mm single-sided DD/FET driver release: A17DD-SO8 / A20DD-SO8 / etc

[wight]

@Cereal_killer

the past 2 days I’ve been shopping around for parts to make BU_CK smaller now that I’ve got it up and running well, I looked up this FET cause I likes the sounds of it (the spec’s mentions) thinking it would work as a replacement for the D2PAK I’m using but the RDS (on) is pretty high on it, quite a bit higher than the AOD510.

I dont think it’ll work for my application but I wonder why that doesnt seem to be causing issues in this single cell / DD application, I had assumed the resistance was one of the huge things to watch in this application. I wonder what a better spec’d SO-8 FET would do on these things.

Note I’m not complaining, just thinking out loud. When we were first picking out FET’s when this whole DD method came about one of the largest factors (right behind the current rating) was the RDS (on), why back then was there so much fuss trying to find FET’s with super low resistance if in the end it apparently doesnt matter? Just seems to me 9A to an XM-L is pretty damn good. Would a FET with lower resistance do even more than that?

edit: Alex would you send me the .lbr part for that FET?

I think you must be misinterpreting some part of the datasheet. The RDS (on) for this is in the same class as other FETs we use. Just as a sanity check (one can never be too sane, after all…) I did check the respective datasheets just now. Here are the datasheets I referred to: AOD510 & PSMN3R0-30YLD. PSMN3R0-30YLD clearly edges out AOD510 in respect to RDS (on). As we approach 3v the difference becomes more pronounced, again in favor of PSMN3R0-30YLD.

I’ll post the part I use over in Mattaus’s Eagle Libraries thread.