Nexperia USA Inc. BZX8450-C3V9-QR

Overview

BZX8450-C3V9-QR from Nexperia is a low-current Zener voltage regulator diode in SOT23 package, designed for precision biasing and voltage reference in automotive and portable electronics. It delivers 3.9 V nominal regulation at 50 µA test current, ±5 % tolerance, 250 mW total power dissipation, and features AEC-Q101 qualification for under-hood use.

For engineers reviewing the BZX8450-C3V9-QR datasheet, BZX8450-C3V9-QR pinout, BZX8450-C3V9-QR application, or BZX8450-C3V9-QR equivalent, key selection criteria include low-leakage operation at microamp bias, thermal resistance (Rth(j-a) = 500 K/W), differential resistance (≤95 Ω at 5 mA), temperature coefficient (−2.7 mV/K), and automotive-grade reliability validation.

Technical Context

This Zener diode operates in reverse breakdown with a specified working voltage of 3.70 V to 4.10 V at IZ = 50 µA, exhibiting a negative temperature coefficient of −2.7 mV/K and differential resistance ≤95 Ω at 5 mA. Its low test current makes it suitable for battery-sensitive circuits where quiescent current must remain minimal.

The device uses an intentional minor leakage current optimization per AN90031 to improve switching speed and reduce noise-distinct from standard Zeners-and is qualified to AEC-Q101 with junction temperature rating up to 150 °C and ambient range from −55 °C to +150 °C.

Key Specifications

Pinout & Package

Package: SOT23 plastic surface-mount package (2.9 mm × 1.3 mm × 1.0 mm body, 1.9 mm pin pitch), optimized for high-density PCB layouts and reflow/wave soldering per Figures 10–11.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX8450-C3V9-QR, the BZX84-C3V9,115 offers identical electrical specs but lacks automotive qualification and has slightly worse thermal resistance, while MMSZ4684T1G trades qualification and compactness for higher power handling in a less space-efficient package.

Availability

BZX8450-C3V9-QR is available at Aetrix Electronics and suitable for automotive cabin sensors, portable medical monitors, industrial IoT node power management, and automotive infotainment microcontroller reset circuits requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for BZX8450-C3V9-QR 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 mobile markets.

The BZX8450-Q series belongs to Nexperia's automotive-qualified Zener diode product line, engineered specifically for low-current, high-stability voltage reference and biasing functions in harsh-environment electronics.

FAQ

What is the maximum reverse current (IR) at VR = 3.0 V for BZX8450-C3V9-QR?

At VR = 3.0 V and Tamb = 25 °C, the typical reverse current is 2.5 µA, with a maximum of 3.0 µA per Table 8. This low leakage ensures minimal parasitic loading in high-impedance bias networks and supports accurate low-power voltage sensing.

Can BZX8450-C3V9-QR be used in series with another Zener to achieve higher reference voltages?

Yes-its low dynamic impedance (≤95 Ω at 5 mA) and tight tolerance support cascaded configurations. However, thermal coupling between devices must be minimized, and total power dissipation must remain within 250 mW per device; derating is required above 25 °C ambient.

Is the n.c. pin (Pin 2) safe to ground or leave unconnected on PCB?

Pin 2 is internally not connected and must remain unconnected on the PCB-no trace, pad, or via should link it to ground or any net. Grounding it may cause unpredictable leakage or parametric shift due to stray capacitance or contamination paths.

How does the −2.7 mV/K temperature coefficient impact accuracy in a 0 °C to 70 °C operating range?

Over 0 °C to 70 °C, the voltage drift is approximately −189 mV (70 K × −2.7 mV/K), resulting in a 3.9 V nominal output shifting by ±0.189 V-or ±4.8 %-relative to 25 °C baseline. System-level compensation or tighter tempco variants (e.g., B-series) may be needed for sub-1 % stability.