Diodes Incorporated MMBZ5257BTS-7-F

Overview

MMBZ5257BTS-7-F from Diodes Incorporated is a triple-surface-mount Zener diode array in SOT363 package, providing three isolated 33 V ±3.15 V Zener elements with 3.8 mA test current, 58 Ω dynamic impedance at 3.8 mA, and 0.1 µA reverse leakage at 25 V, used for precision voltage regulation and overvoltage protection in compact power management circuits.

For engineers reviewing the MMBZ5257BTS-7-F datasheet, MMBZ5257BTS-7-F pinout, MMBZ5257BTS-7-F application, or MMBZ5257BTS-7-F equivalent, key selection criteria include nominal Zener voltage tolerance (±3.15 V), low thermal resistance (625 °C/W), AEC-Q101 qualification, triple-diode integration in ultra-small footprint, and RoHS-compliant lead-free plating.

Technical Context

This device integrates three electrically isolated Zener diodes in a single SOT363 package, each operating independently with identical electrical characteristics. It supports stable voltage reference generation and transient clamping in space-constrained PCB layouts where discrete placement of three separate Zeners would increase board area and assembly cost.

The array is rated for 200 mW total power dissipation per diode, derates linearly above +25°C ambient per Fig. 1, and exhibits typical capacitance of ~15 pF at 0 V bias (inferred from Fig. 2 curve at 33 V). Its 625 °C/W junction-to-ambient thermal resistance assumes FR4 mounting with recommended pad layout (AP02001).

Key Specifications

Pinout & Package

Package: SOT363 - ultra-small surface-mount plastic package (2.10 mm × 1.30 mm × 0.95 mm), UL 94V-0 rated, moisture sensitivity level 1, lead-free matte tin plating over Alloy 42 leadframe.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C33LT1G and MMBZ5257BS-7-F, MMBZ5257BTS-7-F uniquely delivers three matched, isolated Zener functions in one SOT363 package-reducing component count, minimizing layout asymmetry, and enabling simultaneous regulation of multiple voltage domains without interaction.

Availability

MMBZ5257BTS-7-F is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC I/O protection circuits, medical patient monitor power rails, and telecom PoE PD interfaces requiring stable component supply with AEC-Q101 reliability assurance.

Supply support for MMBZ5257BTS-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 MMBZ52xxBTS series belongs to Diodes' high-reliability Zener diode portfolio, engineered specifically for space-constrained, high-stability voltage reference and protection applications in automotive, industrial, and medical electronics.

FAQ

What is the maximum reverse voltage rating for MMBZ5257BTS-7-F?

The device has no explicit "maximum reverse voltage" rating beyond its Zener breakdown specification. Its reverse leakage is guaranteed ≤0.1 µA at 25 V, and it operates stably up to its nominal 33 V Zener voltage with 3.15 V tolerance. Operation above 34.65 V may cause uncontrolled conduction or thermal runaway unless externally limited by series resistance.

Can MMBZ5257BTS-7-F be used in place of a single Zener diode?

Yes - any one anode-cathode pair (e.g., A1–C1) functions as a standalone 33 V Zener diode with identical specs to the full array. The other two diodes remain electrically isolated and inactive unless biased, making it backward-compatible with single-Zener designs while offering future expansion capability.

Is thermal derating required for operation above +25°C ambient?

Yes - the device's 200 mW power rating applies only at +25°C. Above that, power must be reduced linearly at 0.32 mW/°C (per Fig. 1), reaching zero at +150°C. For example, at +85°C ambient, maximum allowable power per diode drops to 180 mW to maintain safe junction temperature.

Does MMBZ5257BTS-7-F support bidirectional transient suppression?

No - it is a unidirectional Zener diode array optimized for forward-biased anode operation and reverse-biased cathode clamping. It does not provide symmetrical surge suppression like a bidirectional TVS diode; for AC line or differential signal protection, a dedicated bidirectional device is required.