LT8607 maximum switch current in overload condition

Question

Hello, 
 I want to use the LT8606 buck converter. For selection of the right inductor I need to know the maximum switch current in an overload condition, as this must be met by saturation current of the inductor. Because some do saturtate hard. Neither in the specifications nor in the block diagram I found something. An overload would damage the converter so fast that temperature shutdown would be too slow to protect. With a LTSPICE simulation it seems to be that max. inductor current is 1.4A. Please provide me the maximum top-switch current in worst case. Thanks.

MarkusHP · Answer

Hello, 
 please check following from the LT8606 datasheet (page 3, sorry for the resolution) : 
 
 1.4A is the max curent limit for the Top FET. 
 And moreover for your saturation considerations (page 14): 
 
 So beside the good approach of using LTSpice for further insights the complete datasheet should be still your primary source for your design work. 
 Add: You'll find the values resp. statement in the LT8607 datasheet as well, both parts differ only in the current limit ratings of the FET. 
 kind regards 
 Markus

Alexxx · Answer

Hello MarkusHP, thanks for your quick response and help! I somehow overlooked the "Top Power NMOS Current Limit" on page 4. Here (LT8607) it is specified with 1.2-2.0 A, typical 1.6 A. A good thing of this mistake is that I now know that there is a similar part with lesser max. current. So I can use a smaller inductor.

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LT8607 maximum switch current in overload condition