1.8V fixed-output LDO for point-of-load regulation
The BD18IC0WHFV-GTR is a single-output positive linear regulator from ROHM Semiconductor, delivering a fixed 1.8V rail at up to 1A from a maximum 5.5V input. The 0.6V maximum dropout at the full 1A load means the input rail needs at least 2.4V to maintain regulation — a 3.3V bus or a 2.5V rail both provide enough headroom for the pass element to stay in the linear region.
Dropout, quiescent current, and protection for a 1A rail
Quiescent current is 0.25 mA typical, and the maximum supply current is 500 µA — the regulator's own draw stays low enough for always-on peripherals on a 5V bus where every milliamp of overhead cuts into the downstream budget. Over-current and over-temperature protection, plus a soft-start circuit, cover the common fault modes on a 1A rail: a shorted load or a hot environment triggers the thermal shutdown before the junction exceeds the safe operating area. The enable control pin lets the system processor gate the 1.8V rail — pulling it low drops the output and cuts the quiescent draw to near zero, useful for sequencing or sleep-mode power gating.