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LTC4368-2 Not powering up/not enabling gate voltage to allow voltage to pass through

Category: Hardware
Product Number: LTC4368HDD-2#WPBF

Hi all, I have a new board made which contacins the LTC4368-2. I am having an issue where no matter what voltage I put on VSUP I get no gate drive and therefore no voltage passing through to VIN. I have checked my resistor values to the equations in the datasheet and it appears to be right? I am wondering if I am missing something obvious? Thanks!

  • At a glance, schematic looks ok.
    Build in LTSpice to convince yourself it works.

    Quick troubleshooting:

    1. Remove regular load from output and replace with a 100ohm to 1k power resistor.
    2. Add a 10k pullup from FAULT# to VSUP so you can check fault status.
    3. Remove R15 to disable UV-OV window.
    4. Apply 12V to VSUP.
    5. What is Vout? What is Vgate? What is Vfault#?
    6. Probe C22 (RETRY pin) - is there a triangle waveform?