Diodes Incorporated MMBZ5256BS-7

Overview

MMBZ5256BS-7 from Diodes Incorporated is a dual isolated 30 V, 4.2 mA Zener diode pair in SOT-363 package, rated for 200 mW power dissipation and 625 °C/W thermal resistance, used for precision voltage reference and overvoltage clamping in low-power analog signal conditioning circuits.

For engineers reviewing the MMBZ5256BS-7 datasheet, MMBZ5256BS-7 pinout, MMBZ5256BS-7 application, or MMBZ5256BS-7 equivalent, key selection criteria include nominal Zener voltage (30 V), test current (4.2 mA), max Zener impedance (49 Ω at 1 kHz), reverse leakage (0.1 μA at 23 V), and SOT-363 dual-diode layout compatibility with space-constrained PCB designs.

Technical Context

This device integrates two independent Zener diodes in a single ultra-small SOT-363 surface-mount package, enabling bidirectional voltage regulation or dual-rail clamping without discrete placement. Each diode exhibits tightly controlled 30 V nominal breakdown (±5% tolerance) with 49 Ω dynamic impedance at 1 kHz and 0.1 μA reverse leakage at VR = 23 V.

Thermal performance is defined by 625 °C/W junction-to-ambient resistance on FR4 board with recommended pad layout, supporting stable operation from –65 °C to +150 °C. The planar die construction ensures repeatable breakdown characteristics under transient pulse conditions per Fig. 6 surge rating.

Key Specifications

Pinout & Package

SOT-363 is a 6-pin ultra-small plastic surface-mount package with dual isolated Zener diodes and two no-connect terminals. Dimensions comply with JEDEC MO-203AA, including 2.0–2.2 mm body length, 1.15–1.35 mm width, and 0.10–0.30 mm thickness.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-Zener voltage reference applications.

Compared with BZX84-C30LT1G and MMBZ5256B-7-F, MMBZ5256BS-7 uniquely delivers two electrically isolated 30 V Zeners in one SOT-363 footprint-enabling compact differential clamping, dual-rail referencing, or space-constrained ESD protection without sacrificing specification fidelity.

Availability

MMBZ5256BS-7 is available at Aetrix Electronics and suitable for industrial sensor interfaces, USB port protection, battery monitor references, and automotive body control modules requiring stable component supply and RoHS-compliant sourcing.

Supply support for MMBZ5256BS-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, specializing in high-reliability components for industrial, computing, and consumer applications.

The MMBZ52xxBS series belongs to Diodes' precision Zener diode product line, engineered specifically for space-constrained voltage regulation, reference, and transient suppression in automated SMT assembly environments.

FAQ

What is the maximum continuous reverse voltage (VR) that MMBZ5256BS-7 can withstand without breakdown?

The device maintains ≤0.1 μA reverse leakage up to VR = 23 V, per Electrical Characteristics table. Breakdown occurs at nominal 30 V (28.5–31.5 V range) when reverse current reaches 4.2 mA. Operation above 23 V but below 28.5 V is permissible only in non-breakdown, high-impedance mode with negligible current flow.

Can both Zener diodes in MMBZ5256BS-7 be used simultaneously in the same circuit?

Yes-C1/A1 and C2/A2 form two fully independent Zener junctions. They share no internal connection, allowing simultaneous use for differential clamping (e.g., across a signal pair), dual-rail referencing (e.g., ±15 V supplies), or redundant protection paths without interaction or crosstalk.

Is MMBZ5256BS-7 suitable for IEC 61000-4-2 Level 4 ESD protection?

Yes-its 30 V breakdown, low 49 Ω impedance, and fast response support robust ESD clamping. When placed within 2 mm of the connector with proper grounding, it achieves ≥15 kV contact discharge protection. However, system-level validation per IEC 61000-4-2 is required to confirm full compliance.

How does the SOT-363 package affect thermal performance compared to SOT-23?

SOT-363 has higher thermal resistance (625 °C/W) than typical SOT-23 Zeners (~400–500 °C/W) due to smaller copper exposure and dual-die layout. Derating begins at 25 °C ambient; at 70 °C, usable power drops to ~140 mW. Layout optimization using thermal vias under exposed pads is strongly recommended.