SLVSFL2A May 2021 – August 2021 TPS7H4002-SP
The device uses the lower voltage of the internal voltage reference or the SS/TR pin voltage as the reference voltage and regulates the output accordingly. A capacitor on the SS/TR pin to ground implements a slow-start time. Equation 5 shows the calculations for the slow-start time (tSS, 10% to 90%) and slow-start capacitor (CSS). The voltage reference (VREF) is 0.807 V and the slow-start charge current (ISS) is 2.5 μA.
When any of the following 3 scenarios occur; the input UVLO is triggered, the EN pin is pulled below 1.05 V, or a thermal shutdown event occurs; the device stops switching and enters low current operation. At the subsequent power-up, when the shutdown condition is removed, the device does not start switching until it has discharged its SS/TR pin to ground ensuring proper soft-start behavior.