Small-signal NPN with high gain in a tiny SMD package
The ROHM 2SD2654TLV is an NPN bipolar junction transistor rated for 50 V collector-emitter breakdown and 150 mA continuous collector current, housed in the compact SC-75 / SOT-416 surface-mount package. Its standout parameter is a minimum DC current gain (hFE) of 820 at 1 mA collector current and 5 V Vce, which makes it suited for low-drive base circuits where a small base current must switch a moderate load. The 250 MHz transition frequency gives it usable bandwidth for small-signal amplification up to VHF and for fast switching in digital interface buffers or oscillator stages. Maximum power dissipation is 150 mW, a typical ceiling for this package size, so continuous operation near the current limit needs thermal derating on the PCB.
A minimum hFE of 820 at 1 mA means the transistor can deliver 50 mA collector current with less than 61 µA of base drive. That relaxes the drive requirement from a GPIO pin or a previous stage, and it keeps the base resistor value low enough to avoid excessive voltage drop. At higher currents the gain will drop, but the 300 mV Vce saturation at 5 mA base and 50 mA collector shows the device saturates hard enough for logic-level switching without wasting headroom.
SC-75 footprint and rework notes
The SC-75 (SOT-416) package measures roughly 1.6 mm x 0.8 mm with a 0.5 mm lead pitch — small enough for dense layouts but demanding on solder paste volume and reflow profile. For hand rework, a fine-tip iron or hot-air station set to 300°C works; avoid prolonged heating beyond 10 seconds to prevent die attach degradation.
It is also ROHS3 compliant.