JAJSBF8B June 2011 – April 2018 TPS54478
PRODUCTION DATA.
The TPS54478 is disabled when the VIN pin voltage falls below 2.6 V. If an application requires a higher under-voltage lockout (UVLO), use the EN pin as shown in Figure 22 to adjust the input voltage UVLO by using two external resistors. It is recommended to use the EN resistors to set the UVLO falling threshold (VSTOP) above 2.6 V. The rising threshold (VSTART) should be set to provide enough hysteresis to allow for any input supply variations. The EN pin has an internal pull-up current source that provides the default condition of the TPS54478 operating when the EN pin floats. Once the EN pin voltage exceeds 1.30 V, an additional 2.76 μA of hysteresis is added. When the EN pin is pulled below 1.21 V, the 2.76 μA is removed. This additional current facilitates input voltage hysteresis.
vertical spacer
Where Ih = 2.76 µA, Ip = 0.64 µA, VENRISING = 1.30 V, VENFALLING = 1.21 V