Texas InstrumentsUnited States

The TPS77401 is a low-dropout (LDO) regulator with power good (PG) function. This device is capable of supplying 250 mA of output current with a dropout of 200 mV. Quiescent current is 92 µA at full load dropping down to 1 µA when device is disabled. This device is optimized to be stable with a wide range of output capacitors including low-ESR ceramic (10-µF) or low-capacitance (1 µF) tantalum capacitors. This device has extremely low noise output performance (55 µV rms ) without using any added filter capacitors. The TPS77401 is designed to have fast transient response for larger load current changes. The TPS77401 is offered in 1.5-V, 1.8-V, 2.7-V, 2.8-V, 3.3-V, and 5-V fixed-voltage versions and in an adjustable version (programmable over the range of 1.5 V to 5.5 V). Output voltage tolerance is 2% over line, load, and temperature ranges. The TPS77401 device is available in an 8-pin mini small-outline package (MSOP) (DGK). Because the PMOS device behaves as a low-value resistor, the dropout voltage is very low (typically 200 mV at an output current of 250 mA for 3.3-V option) and is directly proportional to the output current. Additionally, since the PMOS pass element is a voltage-driven device, the quiescent current is very low and independent of output loading (typically 92 µA over the full range of output current, 0 mA to 250 mA). These two key specifications yield a significant improvement in operating life for battery-powered systems. The device is enabled when the enable ( EN ) pin is connected to a low-level input voltage. This LDO family also features a sleep mode; applying a TTL high signal to EN shuts down the regulator, reducing the quiescent current to less than 1 µA at T J = 25°C. For the TPS77401, the power good (PG) terminal is an active-high output, which can be used to implement a power-on reset or a low-battery indicator. An internal comparator in the TPS77401 monitors the output voltage of the regulator to detect an undervoltage condition on the regulated output voltage. When OUT falls below 82% of its regulated voltage, PG goes to a low-impedance state. PG goes to a high-impedance state when OUT is above 82% of its regulated voltage.