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TCA9535: Grounding A1 causes overheating

Part Number: TCA9535

I have been having great success using the TCA9535 (TSSOP-24 package) as I/O expanders for the Raspberry Pi but I've isolated one peculiar problem.

When the A1 address line is jumpered directly to ground the device will overheat.  I haven't characterized the specifics of the current rate but it takes a matter of hours for the temperature buildup to reach the point where the device is permanently damaged.

I have several PCBs with DIP-24 sockets to accept the 9535 on a breakout board, each PCB set to a different I2C address.  I can swap in different 9535's and they all exhibit the problem on the "grounded A1" boards, but behave fine on a board where the A1 pin is held high.  To seal the deal, I reworked a board so A1 is connected to +5V and it works fine.

I haven't tried grounding A1 with a resistor.  There seems to be no difference whether I'm just running the device standalone (with no ports or I2C lines connected) or when it's operational (device is recognized by the bus master and all ports are connected and commanded to output mode).

I'm moving on since having only four addresses available is plenty but I'd like to know what I might be doing wrong.

"Thanks in advance for any insight you can provide."