Thermal shutdown prevents the device from extreme junction temperatures by turning off the internal switches when the IC junction temperature exceeds 165°C (typical). Thermal shutdown does not trigger below 158°C. After thermal shutdown occurs, hysteresis prevents the device from switching until the junction temperature drops to approximately 155°C. When the junction temperature falls below 155°C (typical), the LM61440-Q1 attempts to soft start.

While the LM61440-Q1 is shut down due to high junction temperature, power continues to be provided to VCC. To prevent overheating due to a short circuit applied to VCC, the LDO that provides power for VCC has reduced current limit while the part is disabled due to high junction temperature. The VCC current limit is reduced to a few milliamperes during thermal shutdown.