MMSZ4x-HF Zener Diodes Comchip Technology MMSZ4x-HF Zener Diodes are halogen-free devices featuring planar die construction and 500mW power dissipation. These Zener diodes include a wide Zener reverse voltage range and are ideally suited for automated assembly processes. The MMSZ4x-HF diodes are constructed with SOD-123, molded plastic case. These Zener diodes operate at -55°C to 150°C temperature range. The MMSZ4x-HF diodes offer 0.9V forward voltage and 150°C junction temperature.