Nexperia USA Inc. BZX84-A18,235

Overview

BZX84-A18,235 from Nexperia is a ±1 % tolerance Zener voltage regulator diode in SOT23 (TO-236AB) package, rated for 18 V nominal breakdown voltage at 5 mA, 250 mW total power dissipation, and 70 Ω maximum differential resistance - used for precision voltage reference and overvoltage protection in low-power analog supply rails.

For engineers reviewing the BZX84-A18,235 datasheet, BZX84-A18,235 pinout, BZX84-A18,235 application, or BZX84-A18,235 equivalent, key selection criteria include Zener voltage tolerance (±1 %), thermal resistance (330 K/W to solder point), non-repetitive peak reverse current (1.5 A), temperature coefficient (+12.6 mV/K), and SOT23 footprint compatibility with automated PCB assembly.

Technical Context

This device operates as a two-terminal shunt regulator, maintaining stable output voltage across a load by conducting reverse current when input exceeds its 18 V Zener threshold. It exhibits a positive temperature coefficient of +12.6 mV/K at I_Z = 5 mA, indicating voltage increases with junction temperature.

Designed for low-power regulation, it supports continuous operation up to 150 °C junction temperature and withstands non-repetitive 100 μs surges up to 40 W. Its 70 Ω differential resistance ensures minimal voltage shift under varying load currents within its 200 mA forward/1.5 A surge rating.

Key Specifications

Pinout & Package

Package: SOT23 (TO-236AB), surface-mount plastic package with 3 leads, 1.9 mm × 1.1 mm body, 0.95 mm height, and standard FR4-compatible footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-A18,235, MMBZ5245B offers higher power but sacrifices voltage accuracy and regulation stiffness; BZX84-C18 matches form-factor and power but lacks the ±1 % tolerance needed for closed-loop feedback stability in precision analog systems.

Availability

BZX84-A18,235 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB-C power delivery reference design, and low-power IoT node power sequencing requiring stable component supply and consistent Zener voltage performance.

Supply support for BZX84-A18,235 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, serving automotive, industrial, and consumer markets with scalable manufacturing and rigorous quality control.

The BZX84 series belongs to Nexperia's precision Zener regulator portfolio, engineered for stable voltage reference and transient suppression in space-constrained, low-power applications where ±1 % tolerance and SOT23 compatibility are essential.

FAQ

What is the maximum continuous reverse current this diode can handle at 25 °C ambient?

The BZX84-A18,235 does not specify a maximum continuous reverse current; instead, its steady-state limit is governed by power dissipation. At 25 °C ambient on an FR4 PCB, it sustains ≤250 mW, corresponding to ~13.9 mA at 18 V. Derating applies above 25 °C per the 500 K/W junction-to-ambient thermal resistance.

Can this Zener diode be used in series with another to achieve higher regulated voltage?

Yes - stacking multiple BZX84-A18,235 diodes in series yields additive Zener voltages (e.g., two yield ~36 V), but tolerance compounds linearly (±2 % total), and thermal coupling between devices may cause mismatched temperature coefficients, reducing overall stability.

Is the "n.c." pin internally connected or should it remain unconnected on the PCB?

Pin 2 is explicitly marked "not connected" in Nexperia's official pinning diagram and has no internal bond wire connection. It must remain unconnected on the PCB; soldering or routing to this pad risks mechanical stress-induced die fracture and parametric shift.

How does the +12.6 mV/K temperature coefficient affect long-term voltage reference stability?

The +12.6 mV/K coefficient means the Zener voltage rises ~12.6 mV per °C increase in junction temperature. Over a 50 °C rise (25 °C to 75 °C), this adds ~630 mV drift - requiring thermal management or compensation in high-stability applications like precision DAC references.