Diodes Incorporated MMSZ5242B-13-F

Overview

MMSZ5242B-13-F from Diodes Incorporated is a 12 V, ±5% tolerance, 500 mW surface-mount Zener diode in SOD123 package, rated for 20 mA test current and 30 Ω dynamic impedance at 1 kHz, used for precision voltage regulation and reference in low-power analog circuits including power supply feedback loops and sensor biasing.

For engineers reviewing the MMSZ5242B-13-F datasheet, MMSZ5242B-13-F pinout, MMSZ5242B-13-F application, or MMSZ5242B-13-F equivalent, key selection criteria include zener voltage tolerance (±5%), thermal resistance (338 °C/W), reverse leakage (<1.0 µA at 9.1 V), and AEC-Q101 qualification for automotive-grade reliability.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load and temperature conditions. It exhibits a nominal temperature coefficient of +0.07 %/°C and supports continuous DC operation with 370 mW power dissipation at 25°C ambient.

The device uses alloy 42 leadframe with matte tin plating, conforms to J-STD-020 Level 1 moisture sensitivity, and features cathode band polarity marking. Its SOD123 package enables automated pick-and-place assembly and meets UL 94V-0 flammability requirements.

Key Specifications

Pinout & Package

Package: SOD123 - surface-mount plastic case with cathode band marking; dimensions: 2.65 mm × 1.55 mm × 1.05 mm (L × D × A); weight ≈ 0.01 g.

Key Features

Applications

Availability

MMSZ5242B-13-F is available at Aetrix Electronics and suitable for automotive ECUs, industrial sensor interfaces, power supply feedback networks, and battery-powered instrumentation requiring stable component supply with AEC-Q101 qualification and long-term lifecycle support.

Supply support for MMSZ5242B-13-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, serving industrial, computing, consumer, and automotive markets with high-reliability components.

This device belongs to the MMSZ52xxB series of general-purpose Zener diodes designed specifically for medium-current voltage regulation and reference in space-constrained, high-volume surface-mount applications.

FAQ

What is the maximum power dissipation of MMSZ5242B-13-F at 75°C ambient?

The device is rated for 500 mW power dissipation at TL = +75°C (lead temperature), as specified in the Absolute Maximum Ratings table. At TA = +25°C, it is limited to 370 mW due to higher thermal resistance to ambient air (338 °C/W). Derating follows the curve in Figure 1, reducing linearly to zero at +150°C.

Is MMSZ5242B-13-F suitable for automotive applications?

Yes - it is explicitly qualified to AEC-Q101 standards for high-reliability automotive use. The "Q" suffix denotes automotive grade, but MMSZ5242B-13-F carries commercial packaging (10,000/reel) and is functionally identical to the Q-qualified version, sharing the same die, process, and test flow per Diodes Incorporated documentation.

How does the SOD123 package affect thermal performance compared to DO-35?

The SOD123 package offers lower thermal resistance to PCB (RθJA = 338 °C/W on FR-4 with 1-inch copper pad) than legacy DO-35 glass packages, enabling better heat spreading in compact layouts. Its molded plastic construction also improves mechanical robustness and eliminates glass breakage risk during reflow or board flexure.

What is the typical Zener impedance at low test currents like 1 mA?

While datasheet values are specified at 20 mA (30 Ω), Figure 5 shows Zener impedance rises sharply below 5 mA - at 1 mA, impedance exceeds 600 Ω for this part. For low-current reference use, consider higher-voltage variants (e.g., MMSZ5250B) which maintain lower ZZK due to steeper breakdown knee.