The TPS74901 is a low-dropout (LDO) regulator that features soft-start capabilities. This regulator uses a low-current bias input to power all internal control circuitry, allowing the NMOS pass transistor to regulate very-low input and output voltages.

Using an NMOS pass transistor offers several critical advantages for many applications. Unlike a p-channel metal-oxide-semiconductor field effect transistor (PMOS) topology device, the output capacitor has little effect on loop stability. This architecture allows the TPS74901 to be stable with any capacitor with a value of 2.2µF or greater. Transient response is also superior to PMOS topologies, particularly for low V_IN applications.

The TPS74901 features a programmable voltage-controlled soft-start circuit that provides a smooth, monotonic start-up and limits start-up inrush currents that can be caused by large capacitive loads. A power-good (PG) output is available to allow supply monitoring and sequencing of other supplies. An enable (EN) pin with hysteresis and deglitch allows slow-ramping signals to be used for sequencing the device. The low V_IN and V_OUT capability allows for inexpensive, easy-to-design, and efficient linear regulation between the multiple supply voltages often present in processor-intensive systems.