Nexperia USA Inc. BZX8450-B33R

Overview

BZX8450-B33R from Nexperia is a low-current Zener voltage regulator diode in SOT23 package, designed for precision biasing and voltage reference in ultra-low-power circuits. It delivers a nominal 33 V regulation at 50 µA test current, with ±2 % tolerance, 250 mW total power dissipation, and 325 Ω differential resistance at 5 mA, enabling stable operation in portable battery-powered sensors and microcontroller reset circuits.

For engineers reviewing the BZX8450-B33R datasheet, BZX8450-B33R pinout, BZX8450-B33R application, or BZX8450-B33R equivalent, this page provides verified electrical characteristics, thermal behavior, SOT23 terminal mapping, and real-world use cases for low-current regulation where leakage control and fast transient response are critical.

Technical Context

This Zener diode operates in reverse breakdown mode with a specified working voltage of 32.3 V to 33.7 V at I_Z = 50 µA, exhibiting a temperature coefficient of +0.05 mV/K and diode capacitance of 45 pF at 0 V. Its non-repetitive peak reverse power dissipation reaches 40 W for 100 µs pulses, supporting surge immunity in compact power rails.

The device features intentional minor leakage current optimization per AN90031 for improved switching speed and noise reduction. Thermal resistance from junction to ambient is 500 K/W on standard FR4 PCB, limiting continuous power handling under natural convection without heatsinking.

Key Specifications

Pinout & Package

SOT23 plastic surface-mounted package: 2.9 mm × 1.3 mm × 1.0 mm body, 1.9 mm lead pitch, single-sided FR4 mounting with tin-plated copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX8450-B33R, BZX84-C33 trades accuracy and noise performance for lower unit cost, while MMSZ5257B offers better thermal handling at the expense of PCB area and assembly compatibility-making BZX8450-B33R optimal for miniaturized, low-leakage, high-stability designs.

Availability

BZX8450-B33R is available at Aetrix Electronics and suitable for portable medical devices, industrial sensor nodes, and IoT edge controllers requiring stable component supply with guaranteed long-term continuity and full traceability.

Supply support for BZX8450-B33R 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 delivering high-performance, reliable discrete, logic, and MOSFET solutions with focus on efficiency, miniaturization, and robustness for mass-market electronics.

The BZX8450 series belongs to Nexperia's precision low-current Zener portfolio, engineered specifically for battery-powered and space-constrained applications demanding tight voltage tolerance, ultra-low leakage, and optimized dynamic response.

FAQ

What is the maximum continuous reverse voltage that BZX8450-B33R can regulate without degradation?

BZX8450-B33R is rated for continuous reverse operation up to its nominal Zener voltage of 33 V, with absolute maximum reverse voltage limited to 33.7 V at I_Z = 50 µA. Exceeding 33.7 V risks irreversible breakdown or parametric shift due to thermal runaway, especially above 25 °C ambient. Derating is required per R_th(j-a) = 500 K/W to maintain T_j ≤ 150 °C.

Can BZX8450-B33R be used in forward-bias mode as a standard silicon diode?

Yes-BZX8450-B33R exhibits a forward voltage ≤ 0.9 V at 10 mA, matching typical silicon diode behavior. However, its anode (Pin 1) and cathode (Pin 3) are asymmetrically constructed for optimized reverse breakdown, so forward conduction is secondary. It is not characterized or guaranteed for sustained forward rectification duty cycles.

How does the "intentional minor rise of leakage current" affect circuit design?

This feature, documented in AN90031, introduces controlled leakage near breakdown to reduce minority-carrier storage time-improving turn-off speed and suppressing high-frequency ringing in feedback loops. Designers benefit from faster transient recovery without adding snubbers, but must verify that added leakage (typically <100 nA above spec) does not compromise ultra-low-power sleep modes.

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

Pin 2 is electrically unconnected (n.c.) per datasheet Table 2 and internal construction. It has no electrical role and must remain floating-no connection, pull-up, or grounding is permitted. Mechanically, it provides structural symmetry for SOT23 mold integrity and thermal balance during reflow, but contributes no thermal path; R_th(j-sp) is measured only at the cathode tab (Pin 3).