Diodes Incorporated MMBZ5228BW-7

Overview

MMBZ5228BW-7 from Diodes Incorporated is a 3.9 V, 200 mW surface-mount Zener diode in SOT323 package, rated for ±5% zener voltage tolerance at 20 mA test current, with 23 Ω dynamic impedance and ≤10 μA reverse leakage at 1.0 V, used for precision voltage regulation and overvoltage protection in low-power analog sensor interfaces.

For engineers reviewing the MMBZ5228BW-7 datasheet, MMBZ5228BW-7 pinout, MMBZ5228BW-7 application, or MMBZ5228BW-7 equivalent, key selection criteria include nominal zener voltage (3.9 V), power rating (200 mW), zener impedance (23 Ω @ 20 mA), reverse leakage (≤10 μA @ 1.0 V), and SOT323 package compatibility with automated PCB assembly.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable reference voltage under varying load and temperature conditions. It features a 3.9 V nominal zener voltage with tight 3.71–4.10 V range at 20 mA, and exhibits low dynamic impedance (23 Ω) ensuring minimal voltage deviation during transient current changes.

Designed for low-power signal conditioning, it delivers predictable clamping behavior with ≤10 μA reverse leakage at VR = 1.0 V and supports operation across –65 °C to +150 °C ambient temperature range, meeting AEC-Q101 reliability requirements for automotive and industrial environments.

Key Specifications

Pinout & Package

Package: SOT323 - 3-terminal plastic surface-mount package measuring 2.10 mm × 1.30 mm × 0.90 mm (L × W × H), with matte tin-plated Alloy 42 leadframe, moisture sensitivity level 1, and UL 94V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX384-B3V9 and MM3Z3V9T1G, MMBZ5228BW-7 offers the lowest zener impedance (23 Ω) in SOT323, delivering superior voltage stability during fast load transitions-critical for sensor biasing where ripple-induced measurement error must stay below 1 LSB.

Availability

MMBZ5228BW-7 is available at Aetrix Electronics and suitable for automotive sensor modules, industrial PLC analog inputs, and portable medical device power monitoring requiring stable component supply and AEC-Q101-compliant Zener regulation.

Supply support for MMBZ5228BW-7 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' AEC-Q101-qualified Zener diode product line, engineered specifically for precision voltage reference and transient suppression in automotive and industrial control systems where reliability and consistency are non-negotiable.

FAQ

What is the maximum continuous reverse current this Zener can handle at 3.9 V?

At 3.9 V, the maximum continuous reverse current is limited by its 200 mW power rating: I_Z(max) = 200 mW ÷ 3.9 V ≈ 51.3 mA. Operation above this current risks thermal runaway unless derated per Fig. 1's ambient temperature curve, especially beyond 25 °C.

Does this part support bidirectional ESD protection?

No. The MMBZ5228BW-7 is a unidirectional Zener diode optimized for reverse-bias regulation and clamping. Its forward voltage is 0.9 V at 10 mA, but it lacks symmetric breakdown characteristics required for bidirectional TVS applications-use dedicated bidirectional TVS diodes like D3V3M1U2LP for such roles.

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

The SOT323 package has a junction-to-ambient thermal resistance of 625 °C/W on FR4, significantly higher than DO-35's ~300 °C/W. This means it reaches thermal limit faster under sustained load; however, its small size enables tighter layout control and better high-frequency transient response due to lower parasitic inductance.

Is the marking code "KG3" visible on the device surface?

Yes. Per the datasheet top-view diagram and marking table, MMBZ5228BW devices are laser-marked with "KG3" on the top surface, followed by a two-character date code (e.g., "B9" for September 2014). This marking is used for traceability and verification against the Electrical Characteristics Table on page 2.