PCA9536: SDA repeatedly has low ground resistance

Christian Schuster

Part Number: PCA9536

Hi,
My team has been using a PCA9536 as a GPIO expander in a battery management system. We are using the LTC6811 to control the GPIO expander, which then controls multiplexers. The GPIO expander has repeatedly failed in the same way where the SDA line gets a low resistance to ground (around 300 ohms) and this causes I2C communication to fail. This same failure mode has happened multiple times across different battery pack locations and on different PCBs. Has this failure mode been seen before and is there anyway to mitigate it?

11 months ago

+1 Clemens Ladisch 11 months ago

Guru 243820 points

Can the SDA line be (un)plugged, or can noise be coupled in from something nearby?

This damage is probably caused by overvoltage. Try adding protection components (plain/ESD/TVS diodes) to clamp voltages to GND and/or V_CC.

0 Christian Schuster 11 months ago in reply to Clemens Ladisch

Prodigy 20 points

The SDA line can be (un)plugged. There likely should be more ESD protection and will add some, it was just strange that it was the same failure on the same data line repeatedly. Thank you.

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PCA9536: SDA repeatedly has low ground resistance