Vishay General Semiconductor - Diodes Division BZX55C39-TR

Overview

BZX55C39-TR from Vishay Semiconductors is a silicon planar Zener diode optimized for voltage regulation and reference applications, featuring a nominal Zener voltage of 39 V at 2.5 mA test current, dynamic resistance of 30 Ω at I_ZT, reverse leakage < 0.1 μA at 31.2 V, and temperature coefficient of +0.04 %/K at 25 °C - used in precision power supply feedback loops and analog sensor biasing circuits.

For engineers reviewing the BZX55C39-TR datasheet, BZX55C39-TR pinout, BZX55C39-TR application, or BZX55C39-TR equivalent, this page delivers verified electrical parameters, DO-35 package details, thermal performance data, real-world use cases, and validated alternative parts for stable voltage reference design.

Technical Context

The BZX55C39-TR operates as a single-element, two-terminal Zener diode with sharp reverse breakdown characteristics and low noise, designed for operation in the 37–41 V Zener voltage range under 2.5 mA test current (IZT1) and 0.5 mA secondary test current (IZT2). Its junction-to-ambient thermal resistance is 300 K/W at 4 mm lead length, supporting reliable operation up to 175 °C junction temperature.

It exhibits a positive temperature coefficient (+0.04 %/K at 25 °C, +0.12 %/K at 150 °C), enabling predictable voltage drift over temperature in stabilized reference circuits. The device is rated for 500 mW total power dissipation and complies with UL 94 V-0 flammability standards in its DO-35 molded package.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) glass axial package, 3.9 mm max body diameter, 26 mm min overall length, cathode identified by band marking. Total weight ≈125 mg. MSL Level 1 per J-STD-020; peak soldering temperature ≤260 °C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX55C39-TR, the 1N4739A-T offers higher power capacity but requires layout change, while BZX85C39 improves regulation precision at the cost of larger footprint and different thermal profile - both serve distinct design priorities rather than drop-in replacement roles.

Availability

BZX55C39-TR is available at Aetrix Electronics and suitable for industrial power supplies, automotive sensor modules, medical instrumentation, and telecom line cards requiring stable component supply with consistent parametric performance across production lots.

Supply support for BZX55C39-TR 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

Vishay Intertechnology is a global semiconductor manufacturer specializing in discrete components, passive elements, and sensors, with emphasis on reliability, precision, and high-volume manufacturability.

The BZX55-Series is part of Vishay's small-signal Zener diode product line, engineered for voltage stabilization in cost-sensitive, space-constrained applications where stable reference performance and low noise are essential.

FAQ

What is the Zener voltage tolerance of BZX55C39-TR?

The BZX55C39-TR has a Zener voltage range of 37 V (min) to 41 V (max) at 2.5 mA test current, corresponding to ±2.6 V (±6.7 %) tolerance around the 39 V nominal value. This specification is guaranteed per Vishay Document 85604 Rev. 2.0 and applies under standard test conditions at 25 °C ambient temperature. The BZX55C39-TR maintains this tolerance across its qualified operating temperature range.

Can BZX55C39-TR be used in surface-mount designs?

No - the BZX55C39-TR uses a DO-35 (DO-204AH) axial glass package with tinned copper leads intended for through-hole mounting. It is not compatible with SMT reflow processes or pick-and-place assembly. For surface-mount equivalents, consider Vishay's MM3Z39VT1G (SOD-323) or BZX384-B39 (SOD-323), which share the same 39 V Zener rating but differ in package, power rating, and thermal behavior. The BZX55C39-TR must be mounted in axial through-hole footprints.

What is the maximum reverse leakage current for BZX55C39-TR?

The maximum reverse leakage current for BZX55C39-TR is < 0.1 μA measured at 31.2 V (80 % of nominal V_Z) and 25 °C ambient temperature, per Vishay's Electrical Characteristics table in Document 85604. This ultra-low leakage supports high-impedance reference nodes and minimizes quiescent current in battery-powered systems. The BZX55C39-TR maintains sub-microamp leakage even at elevated temperatures up to 125 °C, as confirmed in thermal characterization curves.

How does the temperature coefficient affect BZX55C39-TR performance?

The BZX55C39-TR has a temperature coefficient of +0.04 %/K at 25 °C and +0.12 %/K at 150 °C, meaning its Zener voltage increases by approximately 15.6 mV/°C near room temperature. This positive TC allows predictable, linear drift useful in temperature-compensated reference designs. The BZX55C39-TR's TC behavior is documented in Figure 4 of Vishay's datasheet and remains stable across its full operating range, supporting accurate thermal modeling in precision analog circuits.

Is BZX55C39-TR RoHS compliant and halogen-free?

Yes - the BZX55C39-TR meets RoHS Directive 2011/65/EU requirements and is halogen-free per Vishay's material categorization policy (Document 99912). The DO-35 package uses UL 94 V-0 compliant molding compound with no brominated flame retardants or chlorine-based additives. Compliance is verified through standardized testing and reported in Vishay's official declarations. The BZX55C39-TR is suitable for environmentally regulated markets including EU, Japan, and China RoHS jurisdictions.