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Old 1st Dec 2022, 10:34 am   #20
cmjones01
Nonode
 
Join Date: Oct 2008
Location: Warsaw, Poland and Cambridge, UK
Posts: 2,669
Default Re: Linear voltage reg drop out or failure?

Regarding alternatives for the regulators, I find it hard to know what to recommend in this application. Generalizing somewhat: these days linear regulators are only used for small currents (<100mA) or small voltage drops (5V -> 3.3V being a popular one), because efficiency is everything. This is especially relevant when the components are all themselves tiny and packed in to a small space with no heatsinking. For larger powers, regulators are almost always of the switch-mode type. To give an example, attached is a photo of a buck regulator on a board I'm working on at the moment. It takes a nominally 12V input and regulates it down to 5V at up to 5A. It's based on the TI TPS565208 chip (which has since become hard to find, but that's another story...). No heatsink, it's never given any trouble, and you can see its size relative to my thumbnail. Just imagine what a linear regulator capable of dropping 12V to 5V at 5A would look like, with a heatsink to dissipate 35W.

The 78xx regulators might well be the right choice for your application. It's just that I've forgotten how to use them!

Chris
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