Adjustable LDO for post-rectifier and logic rails
It delivers up to 800 mA with a dropout voltage of 1.2 V max at full load, and its output is set by an external resistor divider from a 1.25 V reference.
The 75 dB ripple rejection at 120 Hz is meaningful for designs that regulate a rectified mains supply: it attenuates the 100/120 Hz ripple from a full-wave bridge by a factor of about 5600. That keeps the output clean enough for sensitive analog loads like ADC references or audio preamp rails, as long as the load current stays within the 800 mA ceiling.
Dropout and headroom — the 1.2 V floor
At 800 mA the dropout voltage is 1.2 V max, meaning the input must stay at least 1.2 V above the programmed output to maintain regulation. The maximum input is 15 V, so the part can handle 12 V or 15 V intermediate buses with margin.
Output voltage range and setting
The adjustable output spans from a minimum of 1.25 V up to 13.8 V, set by two external resistors. The quiescent current is 5 mA typical, rising to 10 mA max under heavy load. Protection includes over-current and over-temperature shutdown.
It is not specified for -40°C cold start, so it should not be used in outdoor or automotive applications without qualification testing. The SOT-223 (TO-261-4, TO-261AA) package has a small thermal pad on the tab; a 1-inch-square copper area on the PCB is typical for dissipating the 1.2 V × 800 mA = 0.96 W worst-case dropout heat.