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Hi TIers:
I met a issue on charging board for the automotive, the LM43603 is used to convert the 12V to 5V for the external USB slave device. The schematic is below ,
The issue is that the LM43603 will be damaged during frequently plugging in/out the 12V input . The phenomenon of the failed sample is the SW to VIN, GND, VCC is shorted . And I also ask them to check the input voltage and output voltage when plugging in/out the power .
It indicated that there is under voltage on the VIN and Vout ,the lowest voltage of the 5V will be negative which could damage the chip.
So my question are : a) That's the reason cause the chip damage when plugging in/out the power
b) How to eliminate the bounce of input ?
Blue: 5V output
Yellow: 12Vinput
Hi Frank:
Thanks for your reply.
Customer has add 68uF Al input cap on the input ,and the input ringing is still there ,please see the attached plot. The negative voltage is much higher than the chip could support.
There are constantly coming out the new failed in customer side , we have to find out the root cause asap, Any information you need, please let me know.
Yellow: Input Blue: SW
