9V fixed rail with 300mA headroom
The BD90GA3WEFJ-E2: The ROHM BD90GA3WEFJ- is a single-output positive LDO delivering a fixed 9V at up to 300 mA continuous. The 0.9V max dropout at full load means the input rail needs to stay above 9.9V to keep the output in regulation; below that headroom the pass transistor enters dropout and the output falls off. Quiescent current sits at 0.6 mA typical, with a maximum supply current of 900 µA — the regulator's own draw is low enough for always-on rails in battery-powered equipment where the load spends most of its time in a light sleep state.
Package and thermal interface
Housed in an 8-SOIC with exposed pad (0.154" body width, 3.90 mm), the HTSOP-J package routes the die-attach paddle to the underside of the board. The Enable and Soft Start control pins let the system sequence the rail on startup and limit inrush current into capacitive loads.
Protection and operating envelope
On-chip protection includes over-current limiting and thermal shutdown — the regulator folds back output current when the junction exceeds the die temperature threshold, then re-enables once it cools. The Soft Start feature ramps the output voltage on Enable, preventing a current surge into the output capacitor that could trip the upstream supply. Input voltage range extends to 14V maximum, which covers common 12V rails with margin for ripple. The operating temperature span of -25°C to 85°C covers indoor and sheltered outdoor environments but does not reach automotive grade — for under-hood or engine-bay deployment, a wider-temperature variant would be needed.