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LTC4020 In-rush damage

Question asked by swtaylor on Jul 30, 2018
Latest reply on Jul 30, 2018 by swtaylor

Hi, we are evaluating the LTC4020 Demo circuit (2134a) for a new SLA battery charger design.

During initial testing the charger was working fine.

At one point the LTC4020 IC became damaged and I am wondering if this was somehow due to very high in-rush current that was produced when the battery was connected?   The battery is fairly large 24V 22Ahr SLA type. The IC is shorted (INT_VCC is 1.5ohm to GND).  During testing we have various loads attached each with some capacitance.   I measured about 110A peak in-rush when the battery is connected (with a spark).   The VIN was off when the battery was connected.  Could this in-rush be the cause of the damage and if so how can we protect against future events?  Otherwise what might be the cause of this damage?

Thank you for any suggesting you can provide.