Hello,
We made a design using TPS6590377ZWST and AM5728BABCXEA.
I am trouble shouting one board with the following symptoms:
- The board was powering up correctly on Friday
- The board was not powering up this morning
- PMIC output rails were all to 0V except VRTC_OUT
- When I maintain PWRON or RPWRON shorted to GND, the board powers up for few second then shuts down
- When I briefly short PWRON or RPWRON to GND, the board powers up for few second then shuts down
The configuration of the board is:
- GPIO_7 is pull up to VRTC_OUT (via 0 ohm)
- BOOT0 = 0
- BOOT1 = 1
- PWRON is floating
- RPWRON is floating
- POWERDOWN is pull down to GND (via 10 Kohms)
- NSLEEP is pull up to VRTC_OUT (via 10 Kohm)
- NREWARM is pull up to VRTC_OUT (via 100 Kohm)
- VPROG is pull down to GND (via 0 ohm)
- RESET_IN is pull up to 5V (via 0 ohm)
The intended behavior is that the board is always on. The board power ON/OFF is made by input voltage monitoring using circuitry TPS3808G01DRVR as per suggested by TI.
I have few other boards that seems to work properly.
In my comprehension, it follows indications from Design guide (TPS659037 Design Guide slia088 sept2015.pdf) section 2.6.1 with POWERHOLD always pull up and PMIC_RESET that is used as ON/OFF command.
Do you have any clue to fix the problem?
Thank you for your help