BQ40Z80: BQ40Z80 damaged when connected to the battery

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Part Number: BQ40Z80

I designed a BMS based on the BQ40Z80, featuring separate and parallel charge/discharge paths. I've observed a very strange phenomenon: when a new board is connected directly to the battery (i.e., hard-powered), the BQ40Z80 chip has a high probability of being instantly damaged, manifesting as a complete loss of communication. The specific observations are as follows:

1. This issue does not occur when VBAT is low. However, when VBAT exceeds 24V, the likelihood of failure increases dramatically.

2. I suspect this is caused by input capacitance (C_in) on the board, which—during power-up—creates a resonant condition leading to voltage overshoot that destroys the chip. During debugging, I reduced C_in from 3 µF to 300 nF and added a 3.9 Ω resistor in series at the capacitor input. This nearly eliminated the visible spark during power-up, yet the chip still failed, and the "failure threshold voltage" did not increase.

3. The board actually includes a TVS diode (SMF26A), with its cathode tied to VCC and anode to GND. In theory, because the charge/discharge MOSFETs have body diodes, any voltage spikes originating from either the battery or the CHG_PACK line should be clamped by this TVS.

Could any experts please share insights or suggestions on what might be causing this issue?

Thank you very much in advance for your help!

Schematic diagram (partial)：