The WQFN package has low thermal impedance, which provides good thermal conduction from the silicon to the ambient, to keep junction temperatures low. As added level of protection, the charger converter turns off for self-protection whenever the junction temperature reaches the 155°C. The charger stays off until the junction temperature falls below 135°C. During thermal shut down, the REGN LDO current limit is reduced to 16 mA and stays on. When the temperature falls below 135°C, charge can be resumed with soft start.

When thermal shut down is triggered, TSHUT status bit will be triggered. This status bit keep triggered until host read to clear it. If TSHUT is still present during host read, then this bit will try to be cleared when host read but finally keep triggered because TSHUT still exists.