Taiwan Semiconductor Corporation BZX85C56

Overview

BZX85C56 from Taiwan Semiconductor is a 56 V ±5% tolerance, 1.3 W glass-encapsulated Zener diode in DO-41 package, rated for 120 mA test current (IZT), 2000 Ω dynamic impedance (ZZT), and 0.25 µA leakage at 39 V reverse voltage - used as a precision voltage reference in DC/DC converter feedback networks.

For engineers reviewing the BZX85C56 datasheet, BZX85C56 pinout, BZX85C56 application, or BZX85C56 equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (130 °C/W), junction temperature limit (200 °C), DO-41 mechanical compatibility, and low-leakage performance at near-rated reverse bias.

Technical Context

The BZX85C56 operates as a single-die, cathode-banded, silicon planar Zener diode with hermetically sealed glass package. It delivers stable reverse breakdown at nominal 56 V under 120 mA DC pulse test conditions (10 ms), with ±5% tolerance and specified dynamic impedance measured using 10% RMS AC superimposed on IZT.

Its thermal design relies on DO-41 package characteristics: junction-to-ambient thermal resistance of 130 °C/W, maximum junction temperature of +200 °C, and storage range from –65 °C to +200 °C - enabling reliable operation in ambient temperatures up to +150 °C when derated per power dissipation curves.

Key Specifications

Pinout & Package

DO-41 axial-leaded glass package with cathode indicated by a painted band; leads are pure tin plated and solderable per J-STD-002. No separate anode/cathode pin numbering - device has two terminals: anode (unbanded end) and cathode (banded end).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5388B and BZX55C56, the BZX85C56 offers balanced performance: sufficient 1.3 W power for most mid-range shunt applications, DO-41 compatibility with legacy layouts, and superior thermal resistance over BZX55C56 while avoiding the oversized footprint of 1N5388B.

Availability

BZX85C56 is available at Aetrix Electronics and suitable for low-voltage stabilizers, on-board DC/DC converters, lighting applications, and adapter designs requiring stable component supply with full traceability and RoHS compliance.

Supply support for BZX85C56 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global industrial, automotive, and consumer markets since 1979.

The BZX85 series belongs to TSC's general-purpose Zener diode product line, engineered for cost-effective, high-reliability voltage reference and regulation in through-hole power supply and protection circuits.

FAQ

What is the nominal Zener voltage and tolerance of the BZX85C56?

The BZX85C56 has a nominal Zener voltage of 56 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 52.0 V and 60.0 V when tested at 120 mA under pulse conditions. This tolerance is standardized across the BZX85C series and verified per Taiwan Semiconductor's H2301 specification revision. The BZX85C56 maintains this rating within its full operating temperature range.

What is the maximum power dissipation and thermal resistance of the BZX85C56?

The BZX85C56 is rated for 1.3 W maximum power dissipation at 25 °C ambient temperature, with a junction-to-ambient thermal resistance (R_θJA) of 130 °C/W. Its junction temperature must not exceed +200 °C, and derating is required above 25 °C ambient per the published thermal curve. The BZX85C56 achieves this performance in its DO-41 glass package with tin-plated leads.

How is polarity identified on the BZX85C56, and what is its package type?

The BZX85C56 uses a DO-41 axial-leaded glass package with polarity indicated by a cathode band painted on the body. The banded end is the cathode; the opposite end is the anode. This marking aligns with JEDEC DO-41 standards and is visible before and after soldering. The BZX85C56's mechanical dimensions match HQ2SD07-DO41-059 REV A drawing, including 2.80 mm diameter and 5.20 mm body length.

What is the Zener impedance and leakage current specification for the BZX85C56?

The BZX85C56 exhibits a typical Zener impedance (Z_ZT) of 2000 Ω at 120 mA test current (I_ZT), and a maximum leakage current (I_R) of 0.25 µA at 39 V reverse voltage. These values are measured per Taiwan Semiconductor's H2301 test methodology - Z_ZT derived from 10% RMS AC superimposed on I_ZT, and I_R confirmed at 70% of nominal V_Z. The BZX85C56 maintains these parameters across its qualified temperature range.

Is the BZX85C56 RoHS compliant and suitable for industrial applications?

Yes, the BZX85C56 is RoHS compliant, using green compound encapsulation and lead-free tin-plated leads conforming to J-STD-002 solderability standards. It is rated for junction temperatures up to +200 °C and storage from –65 °C to +200 °C, making it suitable for industrial power supplies, lighting ballasts, and adapter designs. Taiwan Semiconductor explicitly states the BZX85C56 is not intended for medical or life-sustaining applications.