Taiwan Semiconductor Corporation BZX585B43

Overview

BZX585B43 from Taiwan Semiconductor is a surface-mount Zener diode with nominal zener voltage 43 V ±2%, 200 mW power dissipation, 150 Ω maximum zener impedance at 2 mA test current, and SOD-523F package. It provides precise voltage regulation in low-power biasing, reference, and overvoltage protection circuits for portable electronics and sensor interfaces.

For engineers reviewing the BZX585B43 datasheet, BZX585B43 pinout, BZX585B43 application, or BZX585B43 equivalent, key selection criteria include zener voltage tolerance (±2%), low leakage (<0.045 µA at 10 V), temperature coefficient (+10 mV/°C), and MSL1 handling capability for reflow compatibility.

Technical Context

The BZX585B43 operates as a two-terminal voltage reference device, conducting in reverse breakdown to maintain stable voltage across its terminals under controlled current. Its 43 V nominal zener voltage is specified at 2 mA test current (IZT), with dynamic impedance of 150 Ω and temperature coefficient of +10 mV/°C - indicating positive drift with rising junction temperature.

Designed for ambient temperatures up to +150°C and storage from –65°C to +150°C, it features halogen-free epoxy, Pb-free terminations, and guaranteed 260°C/10s soldering tolerance. The SOD-523F package enables high-density PCB layouts while maintaining thermal resistance (RθJA) of 353°C/W.

Key Specifications

Pinout & Package

SOD-523F is a two-terminal surface-mount package with cathode marked by a band. Terminals are non-polarized in function but polarity-sensitive in circuit connection: anode (unmarked 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 MMBZ5265BS-7-F and BZX384-B43,115, the BZX585B43 delivers tighter voltage control at low test current (2 mA), lower leakage (<0.045 µA), and optimized thermal performance in the smaller SOD-523F footprint - making it preferred for space-constrained, low-quiescent-current designs.

Availability

BZX585B43 is available at Aetrix Electronics and suitable for portable power management, sensor signal conditioning, automotive body control modules, and IoT edge node protection requiring stable component supply and full RoHS/halogen-free compliance.

Supply support for BZX585B43 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 is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global industrial, automotive, and consumer markets since 1979.

The BZX585B43 belongs to the Small Signal Product line, engineered for high-reliability voltage reference and protection functions in miniaturized, thermally demanding applications where precision, consistency, and regulatory compliance are critical.

FAQ

What is the zener voltage tolerance of BZX585B43?

The BZX585B43 has a zener voltage tolerance of ±2% at 2 mA test current, meaning its actual breakdown voltage falls between 42.14 V and 43.86 V under standard conditions. This tight tolerance supports accurate voltage referencing in production-grade circuits without calibration. The BZX585B43 achieves this specification across its qualified temperature range and is verified per Taiwan Semiconductor's C1607 datasheet revision.

Is BZX585B43 compatible with lead-free reflow processes?

Yes, the BZX585B43 is qualified for lead-free reflow with guaranteed performance after exposure to 260°C for 10 seconds - meeting IPC/JEDEC J-STD-020 requirements. Its terminations are Pb-free and RoHS compliant, and the SOD-523F package remains structurally and electrically stable under these conditions. The BZX585B43 also carries MSL1 rating, eliminating the need for pre-baking prior to assembly.

What is the maximum reverse leakage current for BZX585B43?

The maximum reverse leakage current (IR) for BZX585B43 is 0.045 µA at 10 V reverse bias and 25°C ambient temperature. This ultra-low leakage preserves signal integrity in high-impedance bias networks and reduces standby power consumption in battery-operated systems. The BZX585B43 maintains this specification across its rated storage temperature range (–65°C to +150°C), as confirmed in the official electrical characteristics table.

Does BZX585B43 have a specified temperature coefficient?

Yes, the BZX585B43 has a nominal temperature coefficient (Tc) of +10 mV/°C at 2 mA test current, indicating its zener voltage increases predictably with rising junction temperature. This value is documented in the "Typical Temperature Coefficient" column of the datasheet's electrical characteristics table and supports thermal compensation design in precision analog circuits using the BZX585B43.

What packaging format is used for BZX585B43?

The BZX585B43 is supplied in 7-inch reels containing 8,000 units per reel (packing code RSG). The SOD-523F package features green compound encapsulation and complies with IEC 61249-2-21 for halogen-free materials. This packaging supports high-speed pick-and-place assembly and is traceable per Taiwan Semiconductor's ordering nomenclature - BZX585B43 RSG denotes the standard reel configuration for the BZX585B43.