Nexperia USA Inc. BZX84W-C43X

Overview

BZX84W-C43X from Nexperia is a ±5 % tolerance Zener diode optimized for voltage regulation and reference functions in space-constrained SMD designs, featuring a nominal Zener voltage of 43 V, 275 mW total power dissipation, 375 Ω typical differential resistance at I_Z = 2 mA, and 41.2 mV/K temperature coefficient - deployed in precision analog supply rails and overvoltage protection circuits.

For engineers reviewing the BZX84W-C43X datasheet, BZX84W-C43X pinout, BZX84W-C43X application, or BZX84W-C43X equivalent, this page delivers verified electrical parameters, SOT323 package layout, thermal performance data, and direct alternative comparisons for stable low-power voltage reference selection.

Technical Context

This Zener diode operates in reverse breakdown with tightly controlled V_Z = 40.0 V to 46.0 V (±5 %) at I_Z = 2 mA, exhibiting 375 Ω differential resistance and 41.2 mV/K temperature coefficient - enabling predictable regulation across industrial ambient ranges (−55 °C to +150 °C).

Its SOT323 package delivers 455 K/W junction-to-ambient thermal resistance on FR4 PCBs, supports non-repetitive peak reverse power up to 40 W (100 µs pulse), and maintains leakage current ≤50 nA at 0.7 × V_Znom, ensuring stability in high-frequency decoupling and reference buffering.

Key Specifications

Pinout & Package

SOT323 (SC-70) leadless surface-mount plastic package: 1.35 mm × 1.75 mm footprint, 0.65 mm pitch, 0.9 mm height, tin-plated terminations compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84W-C43X, BZX84W-B43 offers tighter regulation at higher cost and different test current, while MMBZ5261BS trades single-diode simplicity for dual functionality and higher power - all share SOT323-compatible footprints but differ in thermal derating and leakage behavior.

Availability

BZX84W-C43X is available at Aetrix Electronics and suitable for industrial power monitoring, telecom line protection, medical calibration, and automotive sensor reference requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for BZX84W-C43X 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 high-volume, high-reliability discrete and logic devices, headquartered in Nijmegen, Netherlands, with manufacturing in Asia and Europe.

The BZX84W series belongs to Nexperia's general-purpose Zener diode product line, engineered for compact, cost-effective voltage regulation and reference in consumer, industrial, and communications equipment where SMT scalability and parametric consistency are essential.

FAQ

What is the maximum continuous reverse current the BZX84W-C43X can handle at 25 °C?

The device supports up to 200 mA forward current, but its Zener operation relies on controlled reverse bias. At V_Z = 43 V, the maximum continuous reverse current is derived from P_tot = 275 mW: I_Z(max) = 275 mW / 43 V ≈ 6.4 mA. Exceeding this risks thermal runaway due to 455 K/W R_th(j-a).

Does the 'n.c.' pin on the SOT323 package require PCB routing or grounding?

No. Pin 2 is internally not connected and must remain un-routed and un-soldered. Connecting it risks introducing parasitic capacitance or leakage paths that degrade high-frequency performance and increase reverse leakage beyond the specified 50 nA limit at 0.7 × V_Znom.

How does the temperature coefficient of +41.2 mV/K affect regulation accuracy over −40 °C to +85 °C?

Over this 125 K range, V_Z shifts by +41.2 mV/K × 125 K = +5.15 V - resulting in a potential span from ~38 V to ~48 V. This is inherent to the 43 V Zener physics and must be accommodated in system tolerance budgets; no external compensation is integrated.

Can BZX84W-C43X replace BZX84-C43 in existing designs without layout changes?

Yes - both use identical SOT323 (SC-70) package dimensions and pinout (Anode–n.c.–Cathode). However, BZX84W-C43X has improved thermal resistance (455 K/W vs. ~500 K/W for legacy BZX84) and tighter process control per Rev. 2 datasheet, allowing direct drop-in with enhanced power handling margin.