Hi,
Doing Synchronous Flyback for 48V to 24V, 48W, at 150kHz. Transformer is 1:1.
Need to find synchronous FET with low trr, however, digikey etc don’t sort FETs on their diode’s trr.
Do you know how to get round this?…..ive found that DFN style SMD FETs seem to have lower trr than DPAK or TO220 etc, but is there any other giveaway forlow trr?
I mean, Infineon seem to be the kings of sync fets, btu they are v expensive, eg IPT044N15N5 is £6
https://www.mouser.co.uk/datasheet/2/196/Infineon_IPT044N15N5_DataSheet_v02_02_EN-3362749.pdfFDD120AN15A0 i cheaper at £0.71 but you only get to these after 30mins of searching or so for each fet.
FDD120AN15A0
https://www.digikey.co.uk/en/products/detail/onsemi/FDD120AN15A0/978480(Also, its best if CGD is low, and CGD/CISS <0.02 preferably)
One way round it is to put a UF diode in parallel...it will likely have higher vf than the internal diode, but will still pinch some of the current, so that the internal diode carrys less, and thus has a lower trr effectively....but woudl rather be able to seek the low trr fets directly if poss.