Fixed 10V rail, 1A continuous, SOT-223-4
The LM2940IMP-10/NOPB is a fixed 10V positive-output LDO regulator from Texas Instruments, rated for 1A continuous output current. It comes in a SOT-223-4 surface-mount package (TO-261-4 equivalent), which means the center tab is the output and must be soldered to a copper pad for thermal dissipation — the dropout is only 1V max at full load, so the power dissipated as heat is manageable for a 1A part in this footprint. Input voltage range goes up to 26V, and the fixed 10V output is stable with a 10 µF output capacitor (typical). The 63dB PSRR at 120Hz means it knocks down ripple from a rectified 50/60 Hz supply by about 1000× — useful if the rail feeding it comes from a transformer + bridge rectifier or a noisy DC-DC converter.
Dropout, protection, and temp range
The 1V dropout at 1A sets the minimum input voltage at 11V for a clean 10V output. If the input sags below that, the output follows — no headroom, no regulation. The quiescent current is 10 mA typical, which is not ultra-low but acceptable for always-on rails where the load current is tens to hundreds of mA. Built-in protection covers over-current, over-temperature, reverse polarity, and short circuit — the part shuts down before the die hits 160°C or the output current exceeds about 1.5A.