Diodes Incorporated BZT52C39-7-F

Overview

BZT52C39-7-F from Diodes Incorporated is a surface-mount 39 V Zener diode in SOD123 package, rated for 500 mW peak power dissipation at TL = +75°C and 370 mW at TA = +25°C, with ±5% nominal voltage tolerance (37.0–41.0 V), 130 Ω maximum Zener impedance at 2 mA test current, and 0.1 µA maximum reverse leakage at 33.4 V. It serves as a precision voltage reference or overvoltage clamp in low-power DC regulation circuits.

For engineers reviewing the BZT52C39-7-F datasheet, BZT52C39-7-F pinout, BZT52C39-7-F application, or BZT52C39-7-F equivalent, key selection criteria include its 39 V nominal Zener voltage, SOD123 footprint compatibility, AEC-Q101 qualification for automotive use, thermal resistance (RθJA = 338 °C/W), and low reverse leakage under specified VR.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable voltage across its terminals under controlled current conditions. Its planar die construction ensures consistent breakdown characteristics, while the matte tin–plated Alloy 42 leadframe supports reliable solderability per MIL-STD-202.

The device exhibits a negative temperature coefficient of –3.5 mV/°C below 5 V and transitions toward zero near 39 V, enabling predictable thermal drift behavior in bias networks. Its 0.010 g mass and UL 94V-0 molded plastic case support high-density PCB layouts and automated reflow assembly.

Key Specifications

Pinout & Package

Two-terminal device in SOD123 package: cathode marked by band on body; anode and cathode leads extend from opposite ends of molded plastic case. Dimensions: L = 0.30 mm (lead length), D = 1.55 mm (width), E = 2.65 mm (length), A = 1.05 mm (height).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ5242B-7-F and BZX84-C39, BZT52C39-7-F delivers superior thermal performance in compact SOD123 form factor and certified automotive reliability-critical for designs requiring long-term stability in harsh environments without thermal derating penalties.

Availability

BZT52C39-7-F is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor interfaces, consumer power adapter feedback loops, and medical diagnostic equipment requiring stable component supply and AEC-Q101 assurance.

Supply support for BZT52C39-7-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 automotive, industrial, and computing markets.

BZT52C39-7-F belongs to the BZT52C series of general-purpose Zener diodes designed for medium-current voltage regulation and overvoltage protection in space-constrained, high-volume surface-mount applications.

FAQ

What is the maximum continuous Zener current for BZT52C39-7-F at +25°C ambient?

At TA = +25°C, the device is rated for 370 mW power dissipation. With a nominal Zener voltage of 39 V, the maximum continuous Zener current is approximately 9.5 mA (370 mW ÷ 39 V). Exceeding this value risks thermal runaway unless board-level heatsinking is implemented.

Is BZT52C39-7-F suitable for use in automotive under-hood applications?

Yes - it is qualified to AEC-Q101 standards and rated for operation from –65°C to +150°C junction temperature. Its SOD123 package, matte tin plating, and moisture sensitivity level 1 make it compatible with automotive reflow processes and under-hood thermal cycling requirements.

How does the Zener impedance affect regulation accuracy in a reference circuit?

With a maximum ZZT of 130 Ω at 2 mA, the BZT52C39-7-F introduces up to 1.3 V of voltage variation for every 10 mA change in Zener current. This must be accounted for in feedback divider design to maintain regulation accuracy within ±1% under dynamic load conditions.

Can BZT52C39-7-F replace BZT52C36-7-F in an existing design?

No - the 39 V and 36 V variants have non-overlapping Zener voltage ranges (37.0–41.0 V vs. 34.0–38.0 V). Substitution would shift regulation thresholds by ~3 V, potentially causing overvoltage stress on downstream ICs or failure to trigger protection circuits at intended levels.