Fixed 3.3 V rail at 1.5 A — what the dropout spec means for your input budget
The BD33HC5WEFJ-E2: The BD33HC5WEFJ-: The ROHM BD33HC5WEFJ- is a single-output, fixed 3.3 V positive LDO regulator delivering up to 1.5 A. The dropout voltage is specified at 0.93 V maximum at the full 1.5 A load, which sets the minimum input voltage at about 4.23 V to maintain regulation under worst-case conditions. If your input rail is 5 V nominal, that leaves roughly 770 mV of headroom — comfortable for a well-regulated supply, but tight if the input sags during a cold-crank or brownout event. The quiescent current is 0.6 mA typical, so the part is not a micropower LDO but is reasonable for always-on rails that see moderate load.
Package and thermal — the exposed pad is not optional
The device comes in an 8-HTSOP-J package (8-SOIC footprint with an exposed pad). Without that thermal path, the junction temperature will exceed the 85°C operating limit under continuous full load. The package is rated for surface-mount assembly only.
Built-in protection includes over-current shutdown, over-temperature shutdown, and a soft-start circuit that limits inrush current at power-up. An enable pin allows the output to be gated externally — useful for sequencing multiple rails or shutting down the regulator in standby. The output configuration is fixed positive, so no external resistor divider is needed.
It is ROHS3 compliant.