BUY LR645N5 https://www.utsource.net/itm/p/1030056.html
High Input Voltage SMPS Start-up / Linear Regulator
Description: N-Channel Enhancement Mode MOSFET Features: - Low On-Resistance - Low Input Capacitance - Low Gate Charge - Low Threshold Voltage - Fast Switching Speed - High Input Impedance Applications: - Power Management - Motor Control - Switching Regulators - Load Switching - Battery Management - DC-DC Converters (For reference only)