Fixed 5V LDO for noise-sensitive industrial loads
The LM2940LD-5.0 from Texas Instruments is a fixed 5V positive-output low-dropout regulator rated for 1A continuous output current, with a maximum dropout voltage of 1V at full load. Its 64dB PSRR at 120Hz makes it a candidate for powering analog front-ends, sensor interfaces, and mixed-signal circuits where rail noise couples into the signal path.
Dropout headroom and input voltage budget
With a 26V absolute maximum input and 1V max dropout at 1A, the input rail must stay at least 6V for a clean 5V output under full load — 6V minimum at the regulator pin, not at the bulk cap. The 10 mA quiescent current (15 mA max supply current) is typical for a 1A-class LDO; it is not a micropower part, so always-on battery applications should budget the Iq. Protection features include over-current, over-temperature, reverse polarity, and short-circuit — no external clamp diode needed for reverse-battery scenarios.
The LM2940LD-5.0 carries an official lifecycle status of Obsolete. Sourcing this part means qualifying the supplier's stock — date-code consistency, laser-etch font match, and lot traceability are the screening steps a buyer should run before committing a BOM line, especially if the part is being used in a long-life product that may need a last-time buy or a qualified second-source evaluation.
8-WSON package — thermal and layout notes
The 8-WSON (4x4 mm) exposed pad package requires a thermal land pattern on the PCB to sink heat from the die. The package ships in Tape & Reel, so pick-and-place is standard for volume assembly.