Nexperia USA Inc. BZX38450-B12-QX

Overview

BZX38450-B12-QX from Nexperia is a low-current Zener voltage regulator diode in SOD323 (SC-76) package, rated for 12 V nominal regulation at 50 µA test current, with ±2 % tolerance, 300 mW power dissipation, and AEC-Q101 qualification for automotive use.

For engineers reviewing the BZX38450-B12-QX datasheet, BZX38450-B12-QX pinout, BZX38450-B12-QX application, or BZX38450-B12-QX equivalent, this page delivers verified electrical characteristics, thermal resistance data, cathode/anode terminal mapping, automotive-grade reliability context, and direct alternative part comparisons with documented parameter differences.

Technical Context

This device operates as a precision shunt voltage reference, maintaining stable 12 V output across load variations using reverse-biased Zener breakdown at low bias currents. Its 150 °C maximum junction temperature and 110 K/W junction-to-solder-point thermal resistance support reliable operation in constrained automotive PCB environments.

Specified at I_Z = 50 µA, it achieves 11.8–12.2 V regulation with 150 Ω typical differential resistance and +6.0 mV/K temperature coefficient, enabling low-power sensing and biasing where minimal quiescent current is critical.

Key Specifications

Pinout & Package

SOD323 (SC-76) plastic surface-mount package: 1.7 mm × 1.25 mm × 0.95 mm body, 1.3 mm lead pitch, cathode marked by bar on top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX38450-B12-QX, MMSZ5242B-TP offers higher power but lacks automotive qualification and tight tolerance, while BZX84-C12 matches qualification but sacrifices regulation precision and thermal performance due to larger package and higher dynamic impedance.

Availability

BZX38450-B12-QX is available at Aetrix Electronics and suitable for automotive cabin sensors, portable medical monitors, industrial IoT edge nodes, and automotive body control modules requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for BZX38450-B12-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 high-volume, high-reliability discrete and logic devices, with leadership in automotive-qualified components and advanced packaging technologies.

The BZX38450-Q series belongs to Nexperia's automotive-grade Zener regulator portfolio, engineered specifically for low-current, high-stability voltage reference and clamping in harsh-environment electronic control units.

FAQ

What is the maximum reverse voltage this diode can withstand before breakdown?

The BZX38450-B12-QX has a nominal Zener voltage of 12 V with guaranteed regulation between 11.8 V and 12.2 V at 50 µA. Its absolute maximum non-repetitive peak reverse voltage is defined by the 40 W surge rating at 100 µs pulse width, corresponding to ~126 V at 315 mA peak current. Continuous reverse operation above 12.2 V will cause uncontrolled conduction and thermal runaway unless current-limited.

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

Yes, multiple BZX38450-B12-QX diodes may be connected in series to increase total regulation voltage, but each must share current equally via balancing resistors due to manufacturing spread in Zener voltage (±2 %). Series connection increases total dynamic impedance proportionally and reduces overall power derating margin - for 24 V regulation, total P_tot remains 300 mW, limiting usable current to ~12.5 mA at full regulation.

How does the 50 µA test current affect circuit design compared to standard 5 mA Zeners?

The 50 µA test current means the diode achieves specified regulation at extremely low bias, enabling microampere-level reference circuits. Designers must ensure external current sources or divider networks deliver ≥50 µA under all operating conditions; below this, regulation degrades rapidly. This contrasts with 5 mA Zeners that require 100× more quiescent current but offer lower dynamic impedance.

Is the SOD323 package compatible with standard reflow soldering profiles?

Yes, the SOD323 package is qualified for lead-free reflow soldering per J-STD-020. Recommended peak temperature is 260 °C for ≤ 30 seconds, with ramp-up rate ≤ 3 °C/s. The 0.95 mm height and 1.3 mm pitch align with standard stencil apertures; Figure 10 in the datasheet provides exact solder land dimensions (0.6 mm × 0.5 mm pads with 1.15 mm center-to-center spacing).