Diodes Incorporated MMSZ5256BQ-7-F

Overview

MMSZ5256BQ-7-F from Diodes Incorporated is an automotive-grade 30 V, 4.2 mA nominal Zener diode in SOD-123 package, rated for 500 mW power dissipation at TL = +75°C and 370 mW at TA = +25°C, with 49 Ω dynamic impedance at test current and 0.1 µA reverse leakage at 23 V, used for precision voltage reference and overvoltage protection in automotive body control modules.

For engineers reviewing the MMSZ5256BQ-7-F datasheet, MMSZ5256BQ-7-F pinout, MMSZ5256BQ-7-F application, or MMSZ5256BQ-7-F equivalent, key selection criteria include Zener voltage tolerance (±3.5%), thermal resistance (338 °C/W), AEC-Q101 qualification, SOD-123 footprint compatibility, and low leakage performance under high-temperature bias conditions.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain a stable 30 V reference across varying load currents, with temperature coefficient optimized for mid-voltage range stability (≈+0.07 %/°C per Figure 6). Its 49 Ω Zener impedance at 4.2 mA ensures minimal voltage deviation under moderate dynamic loading.

The device uses alloy 42 leadframe with matte tin plating, qualified to AEC-Q101 for automotive reliability, and features halogen- and antimony-free green molding compound compliant with UL 94V-0 flammability rating and J-STD-020 moisture sensitivity Level 1.

Key Specifications

Pinout & Package

Package: SOD-123 surface-mount plastic case with cathode band marking; dimensions: 2.65 mm × 1.55 mm × 1.05 mm (L × W × H); weight ≈ 0.01 g; RoHS-compliant matte tin finish on alloy 42 leadframe.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C30LT1G and MMSZ5256BS-7-F, the MMSZ5256BQ-7-F delivers guaranteed AEC-Q101 reliability and tighter thermal impedance control in the SOD-123 footprint, making it the only option qualified for under-hood automotive voltage reference and clamping functions requiring long-term stability at 150°C junction temperature.

Availability

MMSZ5256BQ-7-F is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor interfaces, LED driver feedback loops, and portable medical device power supervision requiring stable component supply with full traceability and AEC-Q101 compliance.

Supply support for MMSZ5256BQ-7-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, specializing in high-reliability components for automotive, industrial, and computing markets with ISO/TS 16949-certified production.

The MMSZ52xxB series targets automotive and industrial Zener applications demanding AEC-Q101 qualification, green packaging, and stable voltage reference performance across extended temperature ranges.

FAQ

What is the Zener voltage tolerance for MMSZ5256BQ-7-F at 4.2 mA?

The Zener voltage is specified as 30 V nominal with a minimum of 28.5 V and maximum of 31.5 V at I_ZT = 4.2 mA, representing a ±3.5% tolerance band. This range is confirmed in the Electrical Characteristics table of DS18010 Rev. 28-2 and applies under standard +25°C test conditions with short-duration pulse testing to minimize self-heating effects.

Is MMSZ5256BQ-7-F compatible with lead-free reflow soldering processes?

Yes - the device uses matte tin-plated alloy 42 leadframe and is qualified for lead-free reflow per JEDEC J-STD-020, with moisture sensitivity level 1. The SOD-123 package withstands peak reflow temperatures up to 260°C, and the green molding compound meets UL 94V-0 flammability requirements without halogen or antimony additives.

How does the thermal resistance of MMSZ5256BQ-7-F affect its power handling at elevated ambient temperatures?

With R_θJA = 338 °C/W on FR-4 with 1-inch copper pad, junction temperature rises 338°C per watt. At T_A = +85°C, maximum allowable power drops to ~220 mW to keep T_J ≤ +150°C. Derating follows the curve in Figure 1: linear reduction from 370 mW at 25°C to 0 mW at 125°C ambient.

Can MMSZ5256BQ-7-F be used as a replacement for MMSZ5256BS-7-F in existing designs?

Yes - electrically identical and pin-compatible in SOD-123, but MMSZ5256BQ-7-F adds AEC-Q101 qualification, enhanced thermal cycling endurance, and stricter lot-level screening. No layout or schematic change is needed; however, qualification documentation and traceability records differ, requiring review for automotive PPAP submission.