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Home > Products > Discrete Semiconductor Products > Diodes > Zener > Single Zener Diodes

Nexperia USA Inc. BZX8450-B33-QR

Name: BZX8450-B33-QR
Brand: Nexperia USA Inc.
SKU: BZX8450-B33-QR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX8450-B33-QR

Manufacturer:: Nexperia USA Inc.

Category:: Single Zener Diodes

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BZX8450-B33-QR.pdf

Description:: DIODE ZENER 33V 250MW TO236AB

Quantity:: RFQ Add To RFQ list

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Inventory:6,987

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Product details

Overview

BZX8450-B33-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 a nominal 33 V regulation at 50 µA test current, with ±2 % tolerance, 250 mW total power dissipation, and AEC-Q101 qualification for under-hood applications.

For engineers reviewing the BZX8450-B33-QR datasheet, BZX8450-B33-QR pinout, BZX8450-B33-QR application, or BZX8450-B33-QR equivalent, this page provides verified electrical characteristics, thermal resistance data, leakage behavior at low bias, and automotive-grade reliability context - all critical for low-power analog reference design and ESD-robust signal conditioning.

Technical Context

This device operates as a two-terminal shunt voltage regulator, maintaining stable reverse breakdown at 32.3–33.7 V (B-series ±2 %) with differential resistance ≤325 Ω at 5 mA. Its specified 50 µA test current enables ultra-low quiescent operation ideal for battery-backed sensors and microcontroller reset circuits.

Thermal resistance from junction to ambient is 500 K/W on FR4 PCB, and its intentional minor leakage rise improves switching speed and noise reduction per AN90031. The SOT23 package supports reflow and wave soldering with defined footprint dimensions and solder paste stencil recommendations.

Key Specifications

Parameter	Value and Actual Design Meaning
Nominal Zener Voltage	33 V (min 32.3 V, max 33.7 V at I_Z = 50 µA)
Tolerance	±2 % (B-series tight tolerance for precision reference)
Power Dissipation	250 mW (max at T_amb ≤ 25 °C on standard FR4 PCB)
Forward Voltage	≤ 0.9 V at I_F = 10 mA (low forward drop for bidirectional protection use)
Differential Resistance	≤ 325 Ω at I_Z = 5 mA (ensures stable regulation under small load variations)
Junction Temperature	−55 °C to +150 °C (supports extended automotive temperature range)
AEC-Q101 Qualified	Yes (validated for automotive discrete semiconductor stress testing)

Pinout & Package

Package: SOT23 plastic surface-mount package (2.9 mm × 1.3 mm × 1.0 mm body, 1.9 mm pin pitch), qualified for automotive reflow and wave soldering per Figures 10 and 11.

Pin/Terminal	Circuit Role	Design Meaning
1	Anode (A)	Connected to lower-potential node; reverse-biased during regulation
2	Not Connected (n.c.)	Electrically isolated; no internal connection or bonding wire
3	Cathode (K)	Connected to higher-potential node; defines regulated output reference point

Key Features

Feature	Design Value
Low Test Current Operation	Specified at 50 µA - enables regulation in µA-level bias networks without loading sensitive sources
Optimized Leakage Profile	Intentional minor IR rise reduces switching transients and high-frequency noise in feedback paths
Automotive Qualification	AEC-Q101 compliant - validated for vibration, temperature cycling, and HTRB stress in automotive ECUs
Thermal Performance	R_th(j-a) = 500 K/W on FR4 - allows accurate derating in compact PCB layouts without heatsinking

Applications

Automotive Sensor Biasing

Microcontroller Reset Reference

Use Scenario: Providing stable 33 V reference for analog front-end amplifiers in engine coolant temperature or pressure sensors.

IC Role / Device Role / Timing Role: Shunt voltage reference establishing precise bias point for op-amp input stages.

Use Value: ±2 % tolerance and low 50 µA test current minimize sensor offset drift and extend battery life in always-on modules.

Use Scenario: Generating clean, temperature-stable reset threshold for 3.3 V or 5 V microcontrollers in telematics control units.

IC Role / Device Role / Timing Role: Zener-based voltage monitor triggering POR (power-on reset) circuitry.

Use Value: AEC-Q101 qualification ensures reliable reset assertion across −40 °C to +125 °C ambient conditions.

Portable Battery Monitoring

Industrial Signal Conditioning

Use Scenario: Scaling high-voltage battery packs (e.g., 24–48 V Li-ion) down to ADC-input range using resistive divider with reference stabilization.

IC Role / Device Role / Timing Role: Low-current voltage clamp stabilizing divider midpoint against supply ripple.

Use Value: 250 mW rating and 325 Ω r_diff maintain accuracy even with ±10 % input variation and minimal board space.

Use Scenario: Protecting analog inputs of PLC I/O modules from overvoltage while preserving signal integrity.

IC Role / Device Role / Timing Role: Bidirectional clamping element (forward + reverse) limiting transient excursions.

Use Value: 0.9 V forward voltage and controlled leakage reduce insertion loss and avoid false triggering in 4–20 mA loops.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BZX84-C33-Q	±5 % tolerance (C-series), higher leakage at low bias, same SOT23 package	Less precise regulation; suitable for non-critical bias where cost is prioritized over stability	Select when ±5 % tolerance is acceptable and AEC-Q101 is not required
MMSZ5256B-TP	±5 % tolerance, 500 mW P_tot, 33 V nominal, no AEC-Q101 qualification	Higher power handling but unqualified for automotive; lacks optimized leakage profile	Choose for industrial power supplies needing higher dissipation, not automotive environments

Compared with BZX8450-B33-QR, the BZX84-C33-Q trades precision for cost and broader availability, while MMSZ5256B-TP offers higher power margin but omits automotive qualification and low-bias noise optimization - making BZX8450-B33-QR uniquely suited for AEC-Q101-compliant, low-noise analog references.

Availability

BZX8450-B33-QR is available at Aetrix Electronics and suitable for automotive sensor biasing, microcontroller reset reference, and portable battery monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BZX8450-B33-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 high-volume, high-reliability logic, discrete, and MOSFET solutions, with deep expertise in automotive-qualified components.

The BZX8450-Q series belongs to Nexperia's automotive-grade Zener regulator portfolio, engineered specifically for low-current, low-noise voltage reference in harsh-environment electronics such as ADAS sensors and body control modules.

FAQ

What is the maximum reverse voltage before breakdown for BZX8450-B33-QR?

The BZX8450-B33-QR has a nominal Zener voltage of 33 V with a guaranteed range of 32.3 V to 33.7 V at 50 µA test current. Its absolute maximum non-repetitive peak reverse voltage is not specified; instead, it is rated for 40 W non-repetitive surge (tp = 100 µs) and must remain within its 250 mW steady-state dissipation limit under continuous operation.

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

Pin 2 is electrically unconnected (n.c.) - no internal semiconductor junction or bond wire connects to it. It serves only as a mechanical lead for SOT23 package alignment and solder joint reliability; routing traces to it is unnecessary and may risk unintended coupling in high-impedance analog nodes.

How does the "intentional minor rise of leakage current" improve performance?

Per AN90031, the controlled increase in reverse leakage at low bias reduces minority-carrier storage time, enabling faster turn-off during transient suppression and lowering high-frequency noise generation in feedback loops - critical for precision analog references in automotive sensor interfaces.

Can BZX8450-B33-QR be used in forward conduction mode?

Yes - its forward voltage is specified ≤ 0.9 V at 10 mA, making it usable as a low-drop rectifier or ESD clamp in bidirectional protection schemes. However, its primary design intent and characterization are for reverse-biased Zener regulation; forward-mode current must stay within the 200 mA absolute maximum rating.

BZX8450-B33-QR Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: BZX8450-Q

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 33 V

Tolerance:: ±2%

Power - Max:: 250 mW

Impedance (Max) (Zzt):: 80 Ohms

Current - Reverse Leakage @ Vr:: 50 nA @ 25 V

Voltage - Forward (Vf) (Max) @ If:: 900 mV @ 10 mA

Operating Temperature:: 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: TO-236AB

BZX8450-B33-QR FAQ

1.How can I place an order for BZX8450-B33-QR through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX8450-B33-QR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BZX8450-B33-QR reliable?

The price and inventory of BZX8450-B33-QR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX8450-B33-QR is usually 5 days.

3.What payment methods are accepted for BZX8450-B33-QR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX8450-B33-QR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX8450-B33-QR?

BZX8450-B33-QR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX8450-B33-QR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BZX8450-B33-QR?

For technical support, including BZX8450-B33-QR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX8450-B33-QR requirements.

6.How does Aetrix verify that BZX8450-B33-QR is sourced from the original manufacturer or authorized distributors?

All BZX8450-B33-QR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BZX8450-B33-QR meets industry standards.

7.What is the process for return or replacement of BZX8450-B33-QR?

All BZX8450-B33-QR units undergo pre-shipment inspection (PSI). If there is an issue with BZX8450-B33-QR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BZX8450-B33-QR part is unused and in its original packaging.

Return procedure for BZX8450-B33-QR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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