Diodes Incorporated MMBZ5255BS-7-F

Overview

MMBZ5255BS-7-F from Diodes Incorporated is a dual isolated 28 V ±5% Zener diode pair in SOT-363 package, rated for 200 mW total power dissipation, 44 Ω zener impedance at 4.5 mA test current, and 0.1 μA reverse leakage at 21 V, used for precision voltage reference and overvoltage clamping in space-constrained analog signal conditioning circuits.

For engineers reviewing the MMBZ5255BS-7-F datasheet, MMBZ5255BS-7-F pinout, MMBZ5255BS-7-F application, or MMBZ5255BS-7-F equivalent, key selection criteria include nominal zener voltage tolerance (±5%), low leakage (<0.1 μA @ VR = 21 V), dual-diode isolation integrity, thermal resistance (625 °C/W), and RoHS-compliant matte tin plating on Alloy 42 leadframe.

Technical Context

This dual-Zener device integrates two electrically isolated 28 V zener elements in a single ultra-small SOT-363 surface-mount package, enabling compact bidirectional voltage regulation or independent reference generation without cross-coupling. Each diode operates with identical electrical specs: 4.5 mA test current, 44 Ω dynamic impedance at 1 kHz, and guaranteed breakdown within 26.6–29.4 V range at 25 °C.

The planar die construction ensures stable parametric performance across -65 °C to +150 °C operating temperature, while the UL 94V-0 molded plastic case and moisture sensitivity level 1 rating support high-reliability automated PCB assembly without baking preconditioning.

Key Specifications

Pinout & Package

SOT-363 (SC-70-6) package: 6-pin ultra-small outline transistor with dual isolated Zener dies. Dimensions: 2.20 × 1.35 × 0.95 mm (L × W × H); weight ≈ 0.006 g; UL 94V-0 flammability rating; moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C27LT1G and MMBZ5254BS-7-F, MMBZ5255BS-7-F uniquely delivers dual 28 V references in one RoHS-compliant SOT-363, enabling space-constrained bidirectional clamping or matched reference pairs without inter-device mismatch or layout overhead.

Availability

MMBZ5255BS-7-F is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB port ESD protection interface, and automotive body control module (BCM) input protection requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MMBZ5255BS-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 and manufacturing operations across Asia and the Americas.

The MMBZ52xxBS series belongs to Diodes' precision Zener diode product line, engineered specifically for high-density voltage reference and transient suppression in portable, automotive, and industrial electronics where miniaturization and reliability are critical.

FAQ

What is the maximum reverse voltage (VR) that MMBZ5255BS-7-F can withstand without breakdown?

The datasheet specifies a maximum reverse leakage current of 0.1 μA at VR = 21 V. This indicates the device remains in its high-impedance blocking state up to at least 21 V; breakdown begins near the nominal 28 V zener voltage, with full conduction established at 26.6 V (minimum VZ). Operation above 21 V but below 26.6 V is permissible but yields nonlinear, non-regulated behavior.

Can both Zener diodes in MMBZ5255BS-7-F be used simultaneously in the same circuit?

Yes-both Zeners are fully isolated and may be biased independently. The device schematic confirms separate anode/cathode terminals (C1/A1 and C2/A2), allowing concurrent use for dual-rail clamping, complementary reference generation, or redundant protection paths. No internal coupling affects performance when both are active.

Is MMBZ5255BS-7-F compatible with lead-free reflow soldering profiles?

Yes-the device uses matte tin plating over Alloy 42 leadframe and is rated for lead-free reflow. Its moisture sensitivity level 1 classification means it can be placed directly onto PCBs without baking, and it withstands peak reflow temperatures up to 260 °C per J-STD-020D, matching standard Pb-free SAC305 process requirements.

How does the 625 °C/W thermal resistance affect real-world power handling?

At 25 °C ambient, the 200 mW rating applies fully. With RθJA = 625 °C/W, each 100 mW of dissipated power raises junction temperature by 62.5 °C. Thus, at 85 °C ambient, maximum safe continuous power drops to ~100 mW to keep TJ ≤ 150 °C. Derating curves in Figure 1 confirm this linear reduction above 25 °C.