SLVSD02D March 2015 – June 2019 TPS65982
The 3.3-V LDO from VBUS steps down voltage from VBUS to LDO_3V3. This allows the TPS65982 to be powered from VBUS when VIN_3V3 is not available. This LDO steps down any recommended voltage on the VBUS pin. When VBUS is 20 V, as is allowable by USB PD, the internal circuitry of the TPS65982 will operate without triggering thermal shutdown; however, a significant external load on the LDO_3V3 pin may increase temperature enough to trigger thermal shutdown. The VBUS 3.3-V LDO blocks reverse current from LDO_3V3 back to VBUS allowing VBUS to be unpowered when LDO_3V3 is driven from another source. See Table 18 for the recommended external capacitance on the VBUS and LDO_3V3 pins.