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TPS546A24A: Vboot and Vout_command behavior confirme

Part Number: TPS546A24A

Dear team,

Customer would like to set Vboot as 0.8V(floating VSEL pin) and change output voltage by Vout_command by PMBUS after system power on.

They want to double check Vout_command value will not be import in EEPROM and Vboot is always 0.8V in every power on cycle.

Does our concept is right without risk?



  • Hi Ben,

    As you mentioned floating the VSEL pin on the TPS546A24A will set the boot voltage to the EEPROM default of 0.8V. This value may be changed via the PMBus command (21h) VOUT_COMMAND. In order to ensure the VOUT_COMMAND value is not restored upon power up, I recommend setting the VOUT bit of (EEh) MFR_SPECIFIC_30 (PIN_DETECT_OVERRIDE) to 1b and storing this to NVM after the initial power up. This ensures that the VOUT_COMMAND value is derived from the VSEL pin detection upon power up or RESTORE_USER_ALL in which case the device will detect the pin is floating and the output will come up to 0.8V or the EEPROM default. 

    Here is the language detailing this on page 65 of the datasheet:


    Alec Biesterfeld