The MMST3904 with 40V 225mW 200mA NPN SOT-323-3 is a RoHS-compliant Bipolar Transistor (BJT) manufactured by Bourne. It is a small outline surface mount transistor which is rated for 40V, 225mW, and 200mA. This device is mainly used as an interface between high voltage and low voltage, high current circuits, such as switching applications, power supplies, amplifiers, and other analog circuit designs. The MMST3904 offers low noise operation, fast switching times, and low power consumption, and is suitable for a wide range of applications.