onsemi MMSZ5252B

Overview

MMSZ5252B from ON Semiconductor (formerly Fairchild) is a 5% tolerance, 24 V Zener diode in SOD-123 package, rated for 500 mW power dissipation at 25°C, with 33 Ω dynamic impedance at 5 mA test current and 0.25 µA reverse leakage at 19.2 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.

For engineers reviewing the MMSZ5252B datasheet, pinout, applications, or equivalent options, key selection considerations include its 24 V nominal Zener voltage, 500 mW power rating, SOD-123 footprint compatibility, thermal resistance of 340°C/W, and 0.25 µA IR at VR = 19.2 V - all critical for stable reference design in space-constrained industrial sensors and power supply feedback loops.

Technical Context

The MMSZ5252B operates as a silicon planar Zener diode optimized for stable voltage reference generation in reverse-biased mode, with specified Zener voltage tolerance of ±5% and guaranteed performance across −55°C to +150°C junction temperature range. Its 33 Ω Zener impedance at IZ = 5 mA ensures low output variation under load changes.

It features a maximum forward voltage of 0.9 V at IF = 10 mA, enabling use in dual-polarity clamp configurations. Absolute maximum ratings include 500 mW power dissipation and 150°C operating junction temperature, aligning with industrial-grade reliability requirements.

Key Specifications

Pinout & Package

SOD-123 package: 2-terminal surface-mount device with cathode band marking; dimensions 2.7 × 1.4 × 1.0 mm (L × W × H), JEDEC-compliant land pattern.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener diode applications.

Compared with BZX584C24 and 1N5252A, the MMSZ5252B offers optimal balance of SMT compatibility, 500 mW rating, and 33 Ω impedance - making it preferred for new industrial PCB designs requiring reliable 24 V shunt regulation without thermal derating.

Availability

MMSZ5252B is available at Aetrix Electronics and suitable for industrial sensor reference, power supply feedback clamp, and battery voltage monitor applications requiring stable component supply and long-term lifecycle support.

Supply support for MMSZ5252B includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

ON Semiconductor is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, communications, computing, and consumer electronics.

The MMSZ52xxB series was designed specifically for high-reliability, low-power voltage reference and clamping in space-constrained industrial and automotive control systems.

FAQ

What is the nominal Zener voltage of the MMSZ5252B?

The MMSZ5252B has a nominal Zener voltage of 24 V, with a minimum of 22.8 V and maximum of 25.2 V at IZ = 5 mA and TA = 25°C. This 24 V rating makes the MMSZ5252B suitable for applications requiring a stable mid-range reference voltage, such as 24 V industrial bus monitoring and regulated power supply feedback loops. The ±5% tolerance ensures predictable performance without external trimming.

What is the maximum power dissipation rating for the MMSZ5252B?

The MMSZ5252B is rated for 500 mW power dissipation at 25°C ambient temperature, with a thermal resistance of 340°C/W. This means that at 25°C, the junction temperature will rise by 170°C at full power - staying within its 150°C maximum operating junction temperature only if ambient is kept below 80°C or power is derated. The MMSZ5252B must be used with appropriate thermal design in enclosed or high-temperature environments.

Does the MMSZ5252B have a specified forward voltage?

Yes, the MMSZ5252B has a maximum forward voltage of 0.9 V at IF = 10 mA, per the Fairchild/ON Semiconductor datasheet. This specification supports bidirectional clamp configurations and enables use as a low-VF series diode in protection circuits. The forward characteristic is consistent across the MMSZ5200 series, allowing reuse of bias network designs across multiple Zener voltages.

What is the reverse leakage current specification for the MMSZ5252B?

The MMSZ5252B specifies a maximum reverse leakage current (IR) of 0.25 µA at VR = 19.2 V and TA = 25°C. This ultra-low leakage ensures minimal loading of high-impedance voltage dividers and reference networks, preserving accuracy in precision analog circuits like battery monitors and sensor signal conditioning. Leakage remains below 0.1 µA up to 19.2 V, supporting stable operation near the knee region.

Which package type does the MMSZ5252B use?

The MMSZ5252B uses the SOD-123 surface-mount package, measuring 2.7 mm × 1.4 mm × 1.0 mm with a single cathode band marking. This JEDEC-standardized footprint supports automated placement and reflow soldering, and is compatible with industry-standard land patterns. The SOD-123 package provides better thermal performance than smaller packages like SOD-323 while occupying less board area than through-hole alternatives like DO-35.