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PCA9515B: PCA9515B appears to fail after 10 minutes, causing persistent MCU hang

Arnab Nandi
Prodigy 20 points

Part Number: PCA9515B

Hi,

I am using a PCA9515BDGKR between a 3.3 V microcontroller and an SMBus device. The schematic follows the TI datasheet exactly. The system operates normally for about 10 minutes, after which the microcontroller hangs completely. On subsequent power-ups, the hang occurs within seconds. A full power-off (VCC verified at 0 V) and cooldown do not restore operation. The issue reproduced on two separate boards. Whereas bypassing the PCA9515B and connecting SDA/SCL directly eliminates the problem.

What could cause the PCA9515B to progressively degrade or fail permanently in this setup? What practices does TI recommend for reliable operation?

  • 0
    TI__Guru 65858 points

    Hi Arnab,

    Do you have an oscilloscope capture and/or schematic snippet you can share to provide more details on the issue? 

    What are the pull-up resistors selected on both sides of the buffer?

    What is the VOL and IOL specs of your MCU and the SMBus target? 

    Regards,

    Tyler