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LTC3637 - 24V automotive drop-down to 12V & 5V

Question asked by KIRAMEK on Jan 25, 2018
Latest reply on Feb 5, 2018 by Chaz

I have been reading through the LTC3637 datasheet with the aim of designing a drop-down 1A-max power supply for a mass-produced device that will be installed in 24V vehicles (e.g., trucks, heavy equipment, etc.).  The power supply must have reverse polarity protection as well as 202V load dump protection, and must accept at least double the typical input voltage (48V) in case of battery jump-starts.  Primary output must be 12V, and I also need a 5V @100mA supply for an MCU. I believe the best way to achieve the 5V supply is to just attach an LDO to the 12V output.  


Attached is the schematic of my current design.  Note that Vprg1 & Vprog2 & SS are connected together, also noting resistance values for R1R2.  Those values are exactly the same as presented in the example on the Linear website, on the LTC3637 page, but strangely that product page and many others are not accessible today -- you must Google for "linear LTC3637" and then open the cached version of the page to see it.  Does anyone know why?


I would appreciate hearing from someone experienced with the LTC3637 to know if my attached design is optimal for my intended application.


Thank you.