Nexperia USA Inc. BZX84W-B4V7-QX

Overview

BZX84W-B4V7-QX from Nexperia is a ±2% tolerance Zener voltage regulator diode in SOT323 (SC-70) package, rated for 4.7 V nominal Zener voltage at 5 mA, 275 mW total power dissipation, and qualified to AEC-Q101 for automotive use. It provides stable voltage reference in low-power regulation circuits, ESD protection clamping, and biasing networks in engine control units and body electronics.

For engineers reviewing the BZX84W-B4V7-QX datasheet, BZX84W-B4V7-QX pinout, BZX84W-B4V7-QX application, or BZX84W-B4V7-QX equivalent, key selection criteria include Zener voltage tolerance (±2%), thermal resistance (455 K/W), reverse leakage current (3 µA at VR = 2 V), and automotive qualification status.

Technical Context

This Zener diode operates in reverse breakdown mode with a specified Zener voltage of 4.61 V to 4.79 V at IZ = 5 mA, differential resistance of 500 Ω max at IZ = 1 mA and 80 Ω max at IZ = 5 mA, and temperature coefficient of −1.4 mV/K at IZ = 5 mA. Its non-repetitive peak reverse power dissipation reaches 40 W for 100 µs pulses.

The device features a not-connected (n.c.) terminal (Pin 2), enabling layout flexibility in high-density PCB designs while maintaining anode–cathode isolation. Thermal performance is characterized with Rth(j-a) = 455 K/W on FR4 single-sided copper, defining its derating behavior above 25 °C ambient.

Key Specifications

Pinout & Package

SOT323 (SC-70) leadless surface-mount plastic package with 3 terminals, 1.3 mm × 1.8 mm footprint, 0.65 mm pitch, and 0.25 mm maximum height - optimized for automated placement and reflow soldering in space-constrained automotive modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84W-C4V7-Q, the BZX84W-B4V7-QX offers tighter regulation for calibrated analog functions; versus MMSZ4700T1G, it delivers automotive reliability in half the PCB area but at lower power rating.

Availability

BZX84W-B4V7-QX is available at Aetrix Electronics and suitable for engine control units, infotainment power sequencing, and ADAS camera bias networks requiring stable component supply with automotive-grade traceability and long-term lifecycle support.

Supply support for BZX84W-B4V7-QX 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

Nexperia is a global semiconductor expert focused on essential efficiency technologies, delivering high-performance, reliable discrete, logic, and MOSFET solutions for automotive, industrial, and consumer markets.

The BZX84W-Q series belongs to Nexperia's automotive-qualified Zener diode product line, engineered specifically for robust voltage regulation and transient suppression in harsh-temperature vehicle subsystems.

FAQ

What is the maximum continuous reverse current this Zener can handle at 4.7 V?

The BZX84W-B4V7-QX does not specify a maximum continuous reverse current (IZ) directly; instead, its safe operating limit is defined by power dissipation. At 4.7 V, the maximum DC reverse current is 58.5 mA (275 mW ÷ 4.7 V), assuming Tamb = 25 °C and no thermal derating. Actual usable IZ must be reduced per Rth(j-a) = 455 K/W to maintain Tj ≤ 150 °C.

Is Pin 2 truly unconnected, or does it serve a mechanical function?

Pin 2 is electrically not connected (n.c.) - no internal semiconductor junction or bond wire links to it. Its sole purpose is mechanical: providing structural symmetry and solder joint stability in the SOT323 package during reflow. It may be left floating or grounded for EMI shielding, but grounding adds no electrical functionality.

How does the −1.4 mV/K temperature coefficient affect regulation accuracy over temperature?

At IZ = 5 mA, the −1.4 mV/K coefficient means VZ decreases by 1.4 mV per Kelvin rise in junction temperature. Over a 100 K range (−40 °C to +60 °C), this introduces up to 140 mV drift. For applications needing <±50 mV stability, active compensation or tighter thermal management is required - confirmed by Fig. 7 in the datasheet.

Can this Zener replace a 5.1 V part in an existing design?

No - BZX84W-B4V7-QX has a nominal 4.7 V Zener voltage (4.61–4.79 V), distinct from 5.1 V devices like BZX84W-B5V1-Q (5.00–5.20 V). Substituting would shift regulation points by ~400 mV, potentially causing undervoltage lockout or ADC scaling errors. Cross-reference only within same nominal voltage grade.