BUY PZU3.9B1 https://www.utsource.net/itm/p/5631359.html
Single Zener diodes in a SOD323F package
Description: Zener Diode, 3.9V, 500mW, SOD323 Package Features: Low leakage current Low zener impedance High temperature soldering guaranteed: 260°C/10s at terminals RoHS Compliant AEC-Q101 qualified Applications: Voltage regulation Voltage stabilization Voltage reference Surge protection (For reference only)