BUY KST4401MTF https://www.utsource.net/itm/p/11274182.html
KST4401MTF NPN 60V 0.6A 250MHZ HEF=40~300 SOT23 MARKING 2X
N-Channel Enhancement Mode Field Effect Transistor Features: rn Low On-Resistance rn Low Gate Threshold Voltage rn Fast Switching Speed rn High Input Impedance rn Low Input Capacitance rn High Avalanche Energy rn Low Leakage Current rn Low Noise rn High Frequency Operation rn High Reliability Applications: rn Switching Regulators rn DC-DC Converters rn Motor Control rn Solenoid and Relay Drivers rn Battery Chargers rn DC-AC Inverters rn Low Voltage Logic Circuits rn High Frequency Amplifiers rn High Speed Switching Applications (For reference only)