Diodes Incorporated MMBZ5251BS-7

Overview

MMBZ5251BS-7 from Diodes Incorporated is a dual isolated 22 V, 200 mW surface-mount Zener diode in SOT-363 package, with nominal zener voltage 22 V (min 20.9 V, max 23.1 V), test current 5.6 mA, and zener impedance 29 Ω at 1 kHz; used for precision voltage regulation and overvoltage protection in low-power analog signal conditioning circuits.

For engineers reviewing the MMBZ5251BS-7 datasheet, MMBZ5251BS-7 pinout, MMBZ5251BS-7 application, or MMBZ5251BS-7 equivalent, key selection criteria include zener voltage tolerance, dynamic impedance at specified test current, power derating above 25°C, reverse leakage at rated VR, and dual-diode isolation integrity in compact SOT-363 layout.

Technical Context

This device integrates two electrically isolated Zener diodes in a single ultra-small SOT-363 package, enabling bidirectional clamping or independent reference generation without cross-coupling. Each diode exhibits tight 5% zener voltage tolerance (20.9–23.1 V) and low dynamic impedance (29 Ω at 5.6 mA, 1 kHz).

Thermal performance is defined by 625°C/W junction-to-ambient resistance on FR4 PCB with recommended pad layout, supporting stable operation from –65°C to +150°C. Reverse leakage remains ≤0.1 μA at 17 V, ensuring minimal standby current in battery-sensitive designs.

Key Specifications

Pinout & Package

SOT-363 package features six terminals in a 2.2 mm × 1.35 mm footprint with 0.65 mm pitch; molded plastic case rated UL 94V-0, moisture sensitivity level 1, and matte tin-plated Alloy 42 leadframe.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ5251BS-7, the -7-F variant offers identical performance in optimized packaging, while BZX84-C22LT1G trades dual isolation for higher power and simpler layout-selection depends on whether circuit-level isolation or thermal margin dominates design priority.

Availability

MMBZ5251BS-7 is available at Aetrix Electronics and suitable for industrial sensor interfaces, USB ESD protection circuits, low-power IoT voltage monitoring, and automotive cabin control panels requiring stable component supply and RoHS-compliant sourcing.

Supply support for MMBZ5251BS-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 centers across Asia and manufacturing in China, Taiwan, and the U.S.

The MMBZ52xxBS series belongs to Diodes' precision Zener portfolio, engineered specifically for space-constrained, low-power voltage reference and clamping applications where dual-element isolation and tight tolerance are critical.

FAQ

What is the maximum reverse leakage current for MMBZ5251BS-7 at 17 V?

The maximum reverse leakage current is 0.1 μA at 17 V and 25°C, as specified in the Electrical Characteristics table. This value remains valid up to +150°C ambient, though actual leakage increases exponentially with junction temperature-designers should verify worst-case leakage using the device's thermal resistance (625°C/W) and expected power dissipation.

Can both Zener diodes in the MMBZ5251BS-7 be used simultaneously without interference?

Yes-the two Zener diodes are fully electrically isolated within the SOT-363 package, with no shared substrate or internal connection. Measurements confirm isolation resistance >1 GΩ between A1–A2 and C1–C2 terminals. This allows simultaneous use for independent reference generation, bidirectional clamping, or differential voltage sensing without crosstalk.

Does MMBZ5251BS-7 support reflow soldering per J-STD-020?

Yes-it is qualified for standard Pb-free reflow profiles per J-STD-020D, with moisture sensitivity level 1 (unlimited floor life at ≤30°C/60% RH). The device uses matte tin plating over Alloy 42 leadframe and passes MIL-STD-202 Method 208 solderability testing, making it compatible with automated SMT assembly lines.

How does the 29 Ω zener impedance affect regulation accuracy under load variation?

At 5.6 mA test current, 29 Ω impedance means a ±1 mA load change causes ±29 mV output shift-translating to ±0.13% error at 22 V. For applications requiring tighter regulation, designers should limit dynamic load current swing or add post-regulation filtering; the low impedance also improves high-frequency noise rejection above 10 kHz.