Hi Team,
I am using ADUM1281 IC digital isolator for my UART communication with STM32 MCU. While my Vdd1 is regulated 3V3 from LDO, Vdd2 is an unregulated 5V supply from Recom DC-DC converter ( R1SE-0505). I am using this for my communication isolation purposes on both USART and CAN lines. For CAN, I have used ISO1042 isolator which is also powered from the same source. Both the CAN and ADUM1281 IC's are protected on the signal lines with an ESD diode (PRTR5V0U2AX).
In the current setup, the ADUM IC is not connected to any output device ( open circuit ), only CAN is connected through ISO1042 to external battery and Controller CAN. The output from the DC-DC converter seems stable when testing on bench. But, during bench tests or in-vehicle ( Material Movement Robotics ) product testing, we see that the ESD diode ( PRTR5V0) and the ADUM1281 seems to be failing with a short circuit on the Vdd and Gnd Lines at random. As I have mentioned, I am using only CAN for communication ( only H and L Lines connected while Vdd2 and Gnd2 are dummy) and UART is open circuit. I can understand ESD diode clamping due to ESD / surge events. But, I did not understand how the ADUM IC is failing. Can the Common mode noise voltage from H and L CAN lines travel through PRTR diodes and disturb Vcc rail voltages?
