Wide-VIN BUCK regulator integrates a dedicated thermal sense cell with thermal warning and shutdown thresholds. Thermal warning and shutdown are built-in monitoring and self-protection mechanisms that limit junction temperature and help prevent damage due to thermal overstress.

If the junction temperature exceeds the thermal warning level (T_{WARN_TH}), then the BUCK1_OT_WARN status bit is set. If the BUCK1_OT_WARN_IRQ_EN bit is set to 1b and if the ENDRV/nIRQ pin is driven high, then the ENDRV/nIRQ is driven low to interrupt the external MCU.

If the junction temperature exceeds the thermal shutdown level (T_{STD_TH_R}), the state of the device and BUCK1 regulator depends on the setting of the BUCK1_OT_OFF_EN configuration bit.

If the BUCK1_OT_OFF_EN bit is set to 1b, all of the following occurs:

• The device goes into the OFF state and all regulators are disabled.
• The BUCK1_OT_STD status bit is set and latched in the Analog_Latch, (to preserve it) while the device is in the OFF state, and is presented to the system MCU during the next power-up event from the OFF state.

If the BUCK1_OT_OFF_EN bit is set to 0b, all of the following occurs:

• The BUCK1_OT_STD status bit is set.
• The BUCK1 regulator, BUCK2 regulator, and BOOST converter are disabled, but the resistive discharge circuit is not enabled.
• The device goes into the SAFE state.
  Note:

  Eventually, as the BUCK1 regulator, BUCK2 regulator, and BOOST converter discharges to less than the UV threshold, a global RESET condition is met (as long as one regulator UV event is configured as a RESET event) and the device goes into the RESET state. When the device enters the RESET state, the BUCK1 regulator is enabled again (its default state). After the BUCK1 output exceeds its UV threshold, the BUCK2 regulator is enabled followed by the BOOST converter.

  All the BUCK1 monitoring and protection mechanisms are active and, if any critical condition is still present, the BUCK1 regulator is disabled again. If the BUCK1 regulator never recovers while in the RESET state, the RESET state time-out event puts the device in the OFF state.

• The ENDRV/nIRQ pin is asserted low.
• The device error counter increments.

The junction temperature decreases after the BUCK1 regulator is disabled. In the OFF state, the junction temperature monitor is disabled to reduce power dissipation. The junction temperature monitor is enabled again after the device detects a valid wake-up event. The BUCK1 regulator (and the device) can be restarted only when the junction temperature decreases to less than T_{WARN_TH} – T_{WARN_TH_HYS}.

The device error counter and its power-down threshold is a protection mechanism against multiple restarts caused by a persistent failure condition.