Diodes Incorporated MMBZ5243BW-7-F

Overview

MMBZ5243BW-7-F from Diodes Incorporated is a 13V, 200mW surface-mount Zener diode in SOT323 package, rated for ±5% Zener voltage tolerance at 9.5mA test current, with 13Ω dynamic impedance and 0.5μA reverse leakage at 9.9V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.

For engineers reviewing the MMBZ5243BW-7-F datasheet, MMBZ5243BW-7-F pinout, MMBZ5243BW-7-F application, or MMBZ5243BW-7-F equivalent, key selection criteria include Zener voltage accuracy, low leakage at near-breakdown bias, thermal resistance (625°C/W), and AEC-Q101 qualification for automotive-grade reliability.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable reference voltage under varying load and temperature conditions. Its 13Ω Zener impedance at 9.5mA ensures minimal output voltage variation with current changes, while the 625°C/W junction-to-ambient thermal resistance defines derating behavior above +25°C ambient.

The device uses alloy-42 leadframe with matte tin plating, conforms to J-STD-020D Level 1 moisture sensitivity, and is halogen/antimony-free per Diodes Incorporated's "Green" definition (<900ppm Br, <900ppm Cl, <1000ppm Sb). Polarity is marked on top view with cathode band.

Key Specifications

Pinout & Package

Package: SOT323 - 3-terminal surface-mount plastic case, 0.006g weight, UL 94V-0 flammability rating, compatible with automated pick-and-place and reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX384-B13 and 1SMA5919BT3G, MMBZ5243BW-7-F delivers optimal balance of low leakage (0.5μA), moderate impedance (13Ω), and compact SOT323 packaging - ideal for space- and power-constrained automotive and industrial signal chains where AEC-Q101 validation is mandatory.

Availability

MMBZ5243BW-7-F is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, and portable medical diagnostics requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for MMBZ5243BW-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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

The MMBZ52xxBW series belongs to Diodes' automotive-qualified Zener portfolio, engineered specifically for voltage reference, overvoltage clamping, and biasing in harsh-environment control units where reliability, consistency, and regulatory compliance are critical.

FAQ

What is the maximum reverse voltage (V_R) that MMBZ5243BW-7-F can withstand without breakdown?

The device exhibits 9.9V maximum reverse voltage before reaching its specified 0.5μA leakage threshold - this is not a breakdown rating but the test condition for leakage measurement. True Zener breakdown begins at the minimum V_Z of 12.35V, and operation above 13.65V is outside specification. Exceeding 13.65V risks parametric shift or thermal runaway if power dissipation exceeds 200mW.

Is MMBZ5243BW-7-F suitable for use in a 12V automotive power rail clamp circuit?

Yes - its 13V nominal Zener voltage provides appropriate margin above nominal 12V systems, and AEC-Q101 qualification confirms performance across −40°C to +125°C. With 0.5μA leakage at 9.9V and 13Ω impedance, it clamps transients without loading the rail during normal operation, provided series current limiting keeps dissipation ≤200mW.

How does the SOT323 package affect thermal performance compared to larger packages like DO-35?

The SOT323's 625°C/W R_θJA reflects its small copper area and thin mold compound - it dissipates only 200mW at +25°C and derates linearly to zero at +150°C ambient. In contrast, DO-35 packages achieve ~300°C/W. For reliable operation, use recommended FR4 pad layout (AP02001) and avoid routing heat-sensitive components nearby.

Does MMBZ5243BW-7-F have polarity marking, and how is it identified on the device?

Yes - polarity is marked by a cathode band on the top surface of the SOT323 package, aligned with Pin 2. The top view shows "KH3" marking code followed by date code (e.g., "B9" = September 2014); the band is located adjacent to the cathode terminal, consistent with Diodes Incorporated's standard SOT323 orientation diagram in DS31037.