Diodes Incorporated MMBZ5259BS-7-F

Overview

MMBZ5259BS-7-F from Diodes Incorporated is a dual-isolated 39 V, 3.2 mA Zener diode pair in SOT-363 package, rated for 200 mW power dissipation and 80 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 MMBZ5259BS-7-F datasheet, MMBZ5259BS-7-F pinout, MMBZ5259BS-7-F application, or MMBZ5259BS-7-F equivalent, key selection criteria include nominal Zener voltage (39 V), test current (3.2 mA), maximum reverse leakage (0.1 µA at 30 V), thermal resistance (625 °C/W), and dual-diode isolation in ultra-small SOT-363.

Technical Context

This dual-Zener device integrates two electrically isolated 39 V Zener junctions in a single SOT-363 package, enabling independent voltage regulation or bidirectional clamping without cross-coupling. Each diode exhibits 37.05–40.95 V breakdown range at 3.2 mA and maintains ≤0.1 µA reverse leakage at VR = 30 V.

Thermal performance is defined for FR4 PCB mounting with specified pad layout: 625 °C/W junction-to-ambient resistance enables stable operation up to +150 °C ambient, while derating begins above +75 °C per Figure 1.

Key Specifications

Pinout & Package

SOT-363 surface-mount package with six terminals: two anodes (A1, A2), two cathodes (C1, C2), and two no-connect (NC) pins. Dual diodes share no internal connection-enabling independent use of each Zener pair.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C39LT1G and MMBZ5259B-7-F, MMBZ5259BS-7-F uniquely delivers two isolated 39 V Zeners in SOT-363-enabling space-efficient differential clamping or dual-reference architectures impossible with single-diode alternatives.

Availability

MMBZ5259BS-7-F is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB port ESD protection, and automotive body control module designs requiring stable component supply and RoHS-compliant packaging.

Supply support for MMBZ5259BS-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, specializing in high-reliability components for industrial, automotive, and computing markets.

This device belongs to the MMBZ52xxBS series of dual Zener diodes designed specifically for space-constrained voltage reference and bidirectional transient suppression in high-density PCB assemblies.

FAQ

What is the maximum allowable continuous power dissipation for MMBZ5259BS-7-F at 25°C ambient?

The device is rated for 200 mW continuous power dissipation at TA = 25°C when mounted on an FR4 PCB using the recommended pad layout per AP02001. Derating begins linearly above +75°C ambient, reaching zero dissipation at +150°C per Figure 1 of DS31039 Rev. 15-2.

How are the two Zener diodes isolated within the SOT-363 package?

The two Zener junctions share no internal electrical connection-C1/A1 and C2/A2 form fully independent circuits. The SOT-363 die layout physically separates the junctions, and the NC pins confirm absence of substrate ties. This isolation enables true differential clamping without crosstalk.

Can MMBZ5259BS-7-F be used for bidirectional TVS protection?

No-it is not rated as a TVS device. While it provides clamping at 39 V in reverse bias, its 200 mW rating and 80 Ω impedance are insufficient for surge energy absorption. It functions as a precision Zener reference or low-energy clamp, not a transient voltage suppressor per IEC 61000-4-2.

What does the "S" suffix in MMBZ5259BS-7-F indicate?

The "S" denotes the dual-diode variant in SOT-363 package. Diodes Incorporated uses "S" to distinguish this dual-isolated configuration from single-diode versions like MMBZ5259B-7-F (SOT-23) and MMBZ5259BLT1G (SOT-23). The marking code "KM4" on the device confirms the 39 V rating.