MMSZ5259BT1G

The MMSZ5259BT1G is a 39V Zener diode from onsemi, part of the MMSZ52xxxT1G series of 500mW surface mount Zener voltage regulators. It offers a nominal Zener voltage of 39V with a tolerance of ±5%, making it suitable for precision voltage reference and regulation applications. The device is designed for general purpose, medium current use and provides reliable overvoltage protection.

Key electrical specifications include a maximum forward voltage of 900mV at 10mA, a Zener impedance of 80Ω, and a reverse leakage current of 100nA at 30V. The diode is rated for continuous power dissipation of 500mW on standard FR-4 or FR-5 boards, with derating above 75°C. It operates over a junction temperature range of -55°C to +150°C and features a thermal resistance of 340°C/W junction-to-ambient.

The MMSZ5259BT1G is housed in a compact SOD-123 surface mount package, which is optimized for automated board assembly and high density applications. It supports a maximum soldering temperature of 260°C for 10 seconds. The device carries an ESD rating of Class 3 (>16kV) per the Human Body Model and is Pb-Free with UL 94 V-0 flammability rating.

This Zener diode is commonly used in voltage regulation, clamping, and protection circuits across consumer, industrial, and automotive applications. The SZ prefix variant is AEC-Q101 qualified for automotive use.