Dual NPN pre-biased transistor in SOT-353
The Rohm Semiconductor UMG4NTR integrates two NPN pre-biased transistors in a single 5-pin SOT-353 surface-mount package. Each transistor includes a 10 kΩ base resistor (R1) on-chip, eliminating the need for an external bias resistor and reducing component count in switching and driver circuits. The device is rated for a collector-emitter breakdown voltage of 50 V and a maximum collector current of 100 mA, with a transition frequency of 250 MHz. Maximum power dissipation is 150 mW.
The 50 V Vce breakdown gives comfortable headroom for 24 V or 48 V industrial rails, with derating margin for transients. The 100 mA Ic maximum suits low-current switching loads — relay coils, LED indicators, logic-level interface buffers — where a single discrete transistor would be oversized. The 10 kΩ base resistor sets a fixed drive current; for a 5 V logic input, base current is approximately (5 V - 0.7 V) / 10 kΩ ≈ 430 µA, which saturates the transistor at collector currents up to about 43 mA (assuming hFE of 100 at 1 mA). For loads above that, verify saturation margin against the 300 mV Vce(sat) spec at 10 mA.