We are currently trying to integrate a Jetson AGX Xavier Industrial module onto our custom carrier board. Our carrier currently functions correctly with a non industrial variant of the Xavier. After looking through the migration guide, there seemed to be minimal changes that would affect our application given what we utilize on the module. However we are running into an issue electrically with the VDDIN_PWR_BAD signal which indicates, to the Xavier, if the power supply is valid. We used the recommended designs from the OEM design guide provided by Nvidia for the voltage rail monitoring. As such the VDDIN_PWR_BAD signal is controlled via an open drain circuit on the carrier board.
What we are seeing with the industrial AGX is that when the FETs pulling the VDDIN_PWR_BAD signal low get disabled and become high impedance the signal, which should have a 10K pull up to 5V in the module, only reaches 4.3V. This prevents the module from booting which we see as the SYS_RESET signal staying low. We have tested putting our own external pull-up on the signal line, however a very strong pull up of 220 ohms was required to get the voltage up to 5V which enabled the Xavier to boot. We also tested our carrier board without the module on it and are able to pull the VDDIN_PWR_BAD signal to 5V with a 10K pull-up; so the issue seems to be a change in the module itself.
Our questions are what has changed with the VDDIN_PWR_BAD circuit internally in the module that it no longer returns to 5v using the same circuit as the non industrial module? And if the voltage monitoring circuit on the carrier board does need to change, should we use our own pull up resistor or should we use a push pull driver to make sure the signal reaches the required voltages.