Diodes Incorporated BZX84B4V3-7-F

Overview

BZX84B4V3-7-F from Diodes Incorporated is a precision 4.3 V ±2% tolerance Zener diode in SOT23 package, rated for 350 mW power dissipation at 25°C ambient, with 90 Ω maximum Zener impedance at 5 mA test current and 3.0 µA maximum reverse leakage at 1.0 V. It serves as a stable voltage reference or overvoltage clamp in low-power analog signal conditioning and power rail regulation circuits.

For engineers reviewing the BZX84B4V3-7-F datasheet, BZX84B4V3-7-F pinout, BZX84B4V3-7-F application, or BZX84B4V3-7-F equivalent, key selection criteria include Zener voltage tolerance (±2%), thermal resistance (357 °C/W), junction-to-ambient derating behavior, and AEC-Q101 qualification status for automotive-grade reliability.

Technical Context

This device operates in reverse breakdown mode with a nominal Zener voltage of 4.3 V at 5 mA test current (IZT), exhibiting a temperature coefficient of –3.5 mV/°C near room temperature and negligible positive drift above ~70°C. Its low 90 Ω dynamic impedance ensures stable regulation under small-signal load variations.

The SOT23 package enables high-density PCB layouts and compatibility with automated pick-and-place assembly. Thermal performance is defined under two conditions: 350 mW rating assumes terminals held at ambient temperature, while 300 mW applies when mounted on FR-4 with recommended pad layout - critical for sustained power handling in compact designs.

Key Specifications

Pinout & Package

Package: SOT23 - three-terminal surface-mount plastic case with cathode-marked top-side marking (KZH), 2.4 mm × 1.3 mm footprint, 1.1 mm height, and UL 94V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ4685-7-F and BZX84-C4V3, BZX84B4V3-7-F delivers superior voltage accuracy, higher power capability, and automotive-grade reliability - making it the preferred choice for safety-critical or high-stability reference designs.

Availability

BZX84B4V3-7-F is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, USB-C protection circuits, and medical wearable battery management systems requiring stable component supply and long-term lifecycle support.

Supply support for BZX84B4V3-7-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, headquartered in Plano, Texas, with design centers across Asia and manufacturing facilities in China, Taiwan, and the U.S.

The BZX84 series belongs to Diodes' precision Zener diode product line, engineered specifically for high-reliability voltage reference and clamping applications in automotive, industrial, and medical end equipment.

FAQ

What is the maximum reverse voltage (VR) this Zener can withstand before breakdown?

The BZX84B4V3-7-F exhibits a sharp, well-defined reverse breakdown at its nominal 4.3 V Zener voltage when tested at 5 mA. Below 1.0 V reverse bias, leakage remains ≤3.0 µA; no specified absolute maximum non-breakdown voltage is defined because it functions exclusively in controlled reverse conduction - not as a blocking diode.

Is this part suitable for use in a 12 V automotive system's power rail protection?

Yes - the device is AEC-Q101 qualified and rated for 350 mW at 25°C, with a defined derating curve allowing ≥150 mW at +105°C. When used with appropriate series current limiting (e.g., 1 kΩ resistor), it reliably clamps transients up to ISO 7637-2 Pulse 1/2a levels without parametric shift or failure.

How does the –3.5 mV/°C temperature coefficient affect circuit performance?

This negative temperature coefficient means the Zener voltage decreases by approximately 3.5 mV per degree Celsius rise near 25°C. In precision references, this drift must be compensated via circuit topology (e.g., combining with a positive-TC element) or calibrated out - it is not inherently problematic but requires explicit design accounting.

Can BZX84B4V3-7-F replace older BZX84C4V3 parts in existing designs?

Yes, with functional improvement: BZX84B4V3-7-F offers ±2% tolerance versus ±5% for the 'C' version, identical SOT23 footprint and pinout, and added AEC-Q101 qualification. No layout or schematic changes are needed, and performance margins increase in voltage-critical applications.