100 V N-channel — sizing the voltage headroom
The RJK1055DPB-00#J5 is a 100 V N-channel MOSFET from Renesas in the LFPAK (SOT-669) package. The 100 V drain-source rating gives comfortable headroom for 48 V bus rails (2× derating) and can handle 72 V telecom supplies with margin.
Gate charge and switching — driver budget
Total gate charge is 35 nC at 10 V. At a 100 kHz switching frequency, the average gate drive current needed is 3.5 mA — well within the capability of a standard half-bridge driver. The input capacitance Ciss is 2550 pF at 10 V drain-source, which sets the Miller plateau duration and the switching edge rate.
Thermal and package — board-level reality
Maximum power dissipation is 60 W at case temperature, but the junction is limited to 150 °C. The LFPAK (SC-100 / SOT-669) package has an exposed drain pad on the bottom — the PCB copper area under that pad is the primary heat path. For continuous 23 A operation, a 2 oz copper pour of at least 1 in² on the top layer is recommended to keep junction rise within limits.
Lifecycle and compliance — production status
ROHS3 compliant per the listed compliance grade.