Active adjustable LDO in a TO-252 tabbed package
The Texas Instruments LM1117IDT-ADJ/NOPB is a positive adjustable low-dropout regulator rated for 800 mA continuous output. Output voltage is set with two external resistors from a 1.25 V reference up to 13.8 V. The TO-252-3 (DPak) package has a metal tab that conducts heat to the board copper — the tab is the output, so the PCB layout ties it to the load return plane.
With 75 dB of ripple rejection at 120 Hz, this LDO attenuates full-wave-rectified ripple. That matters when the input comes from a bulk capacitor after a bridge rectifier — the output sees microvolts of ripple instead of millivolts. For an adjustable part, the PSRR holds across the output range because the internal error amplifier runs from the unregulated input.
Industrial temperature range and protection
On-chip protection includes over-current and over-temperature shutdown — the part folds back current before the die hits the thermal limit, which saves the board trace from a shorted load.
The NOPB suffix confirms it is lead-free / RoHS-compliant from the factory.