LTC4231 vs LT4356 - FETs on GATE pin question

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[External] Hello, I am working with the LTC4231. Through our discussion, he wondered why the LTC4231 is able to drive 2 FETS directly from the GATE pin but the LT4356 (in Overvoltage Regulator configuration) cannot. vs I noticed that in the comparison he was making, the LTC4231 was in “Battery Hotswap with Reverse Protection” configuration (pg. 1 of the LTC4231 datasheet). Can you help me figure out why these configurations are handled differently with respect to the FETS and GATE pin? I looked at the functional diagram and couldn’t quite piece together the reason for the difference in the two. 
 
 Answer 
 
4231 has a source sense pin, and an internal FET to clamp gate-source together, shutting both FET's down. 4356 doesn't have this source sense pin, so it uses back to back (drain connected) FETs. 2N3904 will turn on when input voltage goes negative, pulling the M1 gate down with it, shutting M1 off. At the same time, GATE will pull the gate of M2 down, shutting off M2

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LTC4231: FAQ