Dual NPN pre-biased transistor in SOT-363
The UMH33NTN from ROHM Semiconductor is a dual NPN pre-biased (digital) transistor array in a 6-pin SOT-363 surface-mount package. With a maximum collector current of 400 mA and a collector-emitter breakdown voltage of 20 V, it suits low-side switching of relays, LEDs, small motors, and logic-level interface circuits in consumer and industrial control applications.
ROHS3 compliant.
Key ratings and their design impact
The 2.2 kΩ base resistor sets the input threshold and saturation drive. At 5 V logic, base current is roughly (5 V – 0.7 V) / 2.2 kΩ ≈ 2 mA, enough to saturate the transistor with a collector load up to 30 mA (Vce(sat) max 100 mV at 3 mA base, 30 mA collector). The 400 mA continuous collector rating and 150 mW power dissipation limit define the load budget — at 20 V Vce, derate continuous current to stay within the package thermal ceiling.