The MMDT4401-7-F is a NPN Bipolar Junction Transistor (BJT) manufactured by Diodes Incorporated. It has a rated voltage of 40V and a power dissipation of 200mW. It is designed for use in a wide range of applications, including switch-mode power supplies, high-frequency amplifiers, and voltage regulators. The transistor comes in a SC-70 surface-mount package, making it suitable for mounting on a circuit board. The MMDT4401-7-F is a robust and reliable electronic part, making it a great choice for many projects.