BQ24075 failures with improper battery connection

Q: BQ24075 failures

We have found some failures on the BQ24075 during proptotype built and test, as below.  We believe that our test jig may allow reverse connection of the battery to the charger. 


A: Re: BQ24075 failures

The substrate should be the lowest potential and if a power source is connected up backwards, it will bias many internal transistors in their reverse state and cause a short.

All external pins should have an internal ESD structure, which should be able to handle up to ~1.0A.  The battery can supply much more current, when connected in reverse (short) and would blow up the IC most of the time.