Fixed 2.5V rail with 300mA headroom
The BD25HA3MEFJ-LBH2 is a single-output positive LDO from ROHM that delivers a fixed 2.5V output at up to 300mA. The 1.2V maximum dropout at full load means the input rail must stay above 3.7V to maintain regulation — a common constraint when deriving a clean 2.5V sensor bias from a 3.3V or 5V bus. An enable pin allows the regulator to be gated by a microcontroller GPIO or power-sequence controller, and integrated soft start limits inrush during turn-on.
Dropout and thermal budget at 300mA
At 300mA, the 1.2V dropout ceiling sets the minimum input voltage at 3.7V. The exposed pad on the 8-HTSOP-J package must be soldered to a PCB copper plane to keep the junction temperature within the -40°C to 105°C range — without that thermal path, the 1.2V × 300mA = 360mW dissipation can push the die above the rated limit in still air. Protection features include over-current and over-temperature shutdown, which guard against output shorts or excessive ambient heat without external clamp diodes.