Other Parts Discussed in Thread: TPS54824, TPS54620
I think I know the answer here, but want to check with the gurus. :)
I have a customer who is driving the EN of the TPS543620 with a PMIC. The PMIC is powered off of the same 12Vin rail that the TPS543620 is powered off of. They need the TPS543620 to power up AFTER the PMIC. However, if we leave EN floating the device turns on. Unfortunately, the PMIC cannot control its EN drive state when powered off (logic state unknown). Because a floating EN still turns on the device, the TPS543620 is powering o when 12V is applied, which is before the PMIC tells it to.
Ideally they would like to avoid a layout change and keep EN low until after the PMIC powers up. Any workarounds here that you can think of?
I'm thinking that a layout change will be necessary here to add in a pull down resistor.
Also, why did we default enable to on? That seems pretty atypical.