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High Icc current seen on unused inputs in a recent lot of TCA9539 Port expanders

Skip Tobey
Prodigy 100 points
Other Parts Discussed in Thread: TCA9539

We have been using the TCA9539 in our battery operated product for about 2 years without issue.

Recently we noticed a very high battery current demand of about 2mA instead of our typical 26uA demand.

We traced this to TCA9539 devices with a top print code of  PW539 29K G4 ASSD. Replacing this with a device marked OAK G4 A89H resolves the issue.

The problem seems to be with I/O ports that are not connected (floating) and set as inputs on the PW539 29K G4 ASSD devices. In the same circut, the devices marked OAK G4 A89H and all previous devices do not exibit this problem.

My questions are:

1. Has there been any changes or production issues in the TCA9539 PW539 29K G4 ASSD that may have created this issue for us.

2. Would setting the unconnected I/O pins to low driven outputs rather than inputs resolve this issue.

Thanks,

Skip Tobey