Diodes Incorporated MMBZ5256BS-7-F

Overview

MMBZ5256BS-7-F from Diodes Incorporated is a dual isolated 30 V ±5% Zener diode pair in SOT-363 package, rated for 200 mW total power dissipation, 4.2 mA test current, and 49 Ω dynamic impedance at 1 kHz; used for precision voltage reference and overvoltage clamping in space-constrained analog signal conditioning circuits.

For engineers reviewing the MMBZ5256BS-7-F datasheet, MMBZ5256BS-7-F pinout, MMBZ5256BS-7-F application, or MMBZ5256BS-7-F equivalent, key selection criteria include nominal Zener voltage (30 V), Zener impedance (49 Ω), reverse leakage (0.1 μA at 23 V), thermal resistance (625 °C/W), and dual-diode isolation in ultra-small SOT-363.

Technical Context

This device integrates two electrically isolated Zener diodes in a single SOT-363 package, enabling bidirectional voltage regulation or independent reference generation without cross-coupling. Each diode operates with a specified 30 V nominal breakdown voltage, 28.5–31.5 V tolerance band, and low 0.1 μA reverse leakage at VR = 23 V.

Designed for surface-mount automated assembly, it features planar die construction, matte tin lead finish over Alloy 42 leadframe, and UL 94V-0 molded plastic case. Thermal performance is defined for FR4 PCB mounting per AP02001 layout, with 625 °C/W junction-to-ambient resistance and -65°C to +150°C operating range.

Key Specifications

Pinout & Package

SOT-363 (SC-70-6) surface-mount package with six terminals: two anodes (A1, A2), two cathodes (C1, C2), and two no-connect (NC) pins. Molded plastic case meets UL 94V-0 flammability rating; moisture sensitivity level 1 per J-STD-020D.

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-F uniquely delivers two isolated 30 V Zeners in one SOT-363 footprint-critical for space-limited dual-rail designs where leakage, matching, and thermal coupling matter.

Availability

MMBZ5256BS-7-F is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB port overvoltage protection, and low-power IoT node voltage reference requiring stable component supply and consistent parametric performance across production lots.

Supply support for MMBZ5256BS-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 MMBZ52xxBS series belongs to Diodes' precision Zener diode product line, engineered specifically for high-reliability, space-constrained voltage reference and transient suppression in industrial, computing, and communications equipment.

FAQ

What is the maximum continuous reverse voltage this device can withstand before breakdown?

The MMBZ5256BS-7-F has a nominal Zener voltage of 30 V with a guaranteed range of 28.5 V to 31.5 V at 4.2 mA test current. It is not rated for continuous reverse blocking above its Zener voltage; operation beyond 31.5 V will initiate controlled conduction. The absolute maximum non-repetitive surge voltage is not specified, but sustained reverse bias above 31.5 V exceeds design intent and risks thermal runaway at full 200 mW dissipation.

Can both Zener diodes be used simultaneously without interference?

Yes-both diodes are fully electrically isolated within the SOT-363 package, with no internal connection between their anodes or cathodes. Electrical testing confirms isolation resistance >10⁹ Ω between C1/A1 and C2/A2 terminals. This allows simultaneous use in independent circuits, such as dual-rail clamping or split-supply references, without crosstalk or shared thermal drift.

Is this part suitable for use in automotive applications per AEC-Q200?

No-MMBZ5256BS-7-F is not AEC-Q200 qualified. While it operates from -65°C to +150°C and meets RoHS requirements, Diodes Incorporated does not list it in their AEC-Q200 stress-tested portfolio. For automotive body control or infotainment systems, consider the AEC-Q200-qualified BZX84-A30LT1G or NZ9F30ST5G, which undergo extended temperature cycling, humidity bias, and mechanical shock validation.

How does the 625 °C/W thermal resistance impact PCB layout?

The 625 °C/W RθJA assumes mounting on FR4 with Diodes' recommended pad layout (AP02001). To maintain junction temperature below 150°C at 200 mW, ambient must stay below 25°C unless copper pour or thermal vias reduce effective resistance. Layout must replicate the 0.65 mm × 1.9 mm pad dimensions per terminal and avoid covering thermal pads with solder mask to ensure conduction through the exposed leadframe.