TPS78833,pdf(150-mA Low-Noise

The TPS78825 and TPS78833 are very small (SOT-23) package, low-noise LDOs that regulate the output voltage to 2.5 V and 3.3 V with input voltage ranging from 2.7 V to an absolute maximum of 13.5 V. These devices output 150 mA with a peak current of 350 mA (typ). The TPS788xx family uses the SR pin to program the output voltage slew rate to control the in-rush current. This is specifically used in the USB application where large load capacitance is present at start-up. The TPS788xx devices use only 17 uA of quiescent current and exhibit only 56 uV _RMS of output voltage noise using a 10 uF output capacitor.

The usual PNP pass transistor has been replaced by a PMOS pass element. Because the PMOS pass element behaves as a low-value resistor, the dropout voltage is very low, typically 150 mV at 150 mA of load current, and is directly proportional to the load current.