3.3V fixed output, 1A continuous — the dropout tells you the headroom
The BD33IC0MEFJ-CE2 is a fixed-output linear regulator delivering 3.3V at up to 1A from a maximum 5.5V input rail. The 0.9V dropout at full load means the input must stay above 4.2V to keep the output in regulation — a 5V rail with a 0.5V diode drop or a 4.5V battery near end-of-life may not hold margin. Part of ROHM's Automotive series with AEC-Q100 qualification, this regulator is built for under-hood and cabin electronics where the ambient temperature spans -40°C to 125°C.
Protection set and quiescent draw
On-chip protection covers over-current, over-temperature, and reverse polarity — the regulator survives a miswired battery connection or a sustained short without latching off permanently. The enable pin lets a microcontroller or ignition signal gate the output, pulling the quiescent current to near zero when the rail is not needed. Quiescent current is 700 µA typical at no load — not an ultra-low-Iq part for always-on modules, but acceptable for loads that spend most of their time active. The 700 µA supply-max figure includes the internal bias; it does not drop much under load because the pass element is a PNP or PMOS running in its linear region.
Package, footprint, and sourcing posture
The supplier device package is listed as 8-HTSOP-J, which is ROHM's designation for the same mechanical outline.