600 mA automotive buck — fixed 1.15 V rail, synchronous rectifier
The BD9SD11NUX-CE2 from ROHM is a single-output step-down buck regulator rated for 600 mA continuous output at a fixed 1.15 V. Synchronous rectification is built in — the internal low-side FET replaces the external catch diode, saving one BOM line and one placement. The efficiency gain matters most at light loads where a diode's forward drop would dominate conduction loss.
This covers under-hood and cabin-mounted ECUs where the local ambient can reach 105°C and the regulator's own dissipation adds another 10-15°C junction rise. ROHS3 compliance is confirmed — no restricted substances in the package or plating.
VSON008X2020 — thermal pad and board-level integration
The 8-UFDFN exposed-pad package (VSON008X2020) requires a thermal land on the PCB to draw heat from the die into the board copper. The exposed pad is the main thermal path — the package's RthJA depends on the number and size of the thermal vias under the pad. Tape & Reel packaging is the standard delivery format; Cut Tape is also available for prototype or low-volume builds. The reel quantity is the usual 3000 pieces for this package size.