1A fixed 1.8V LDO — dropout and PSRR drive the fit
The REG1117A-1.8/2K5 is a fixed-output 1.8V LDO regulator rated for 1A continuous output. PSRR is 62dB at 120Hz, which is the ripple rejection figure for full-wave-rectified line noise. For a 5V rail coming off a linear pre-regulator or a quiet switching supply, this LDO cleans up the 100/120Hz hum well enough for sensitive analog loads like ADC reference or sensor bias. Quiescent current sits at 10 mA — not a micropower part, but acceptable for always-on industrial rails where the load current dominates the power budget. The 15V maximum input gives headroom for 12V or 9V intermediate buses.
Industrial temp range and protection features
The SOT-223-4 package (supplier device package) has a thermal pad on the tab — board copper area sets the effective RθJA, so the 1A output at 125°C ambient requires a reasonable PCB heatsink area to keep the junction below the absolute maximum. Built-in over-current and over-temperature protection latch the output off during a fault and auto-recover when the condition clears.
Active lifecycle and sourcing
Sourced through independent distribution channels.