Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Nexperia USA Inc. BZX8450-B39-QR

Name: BZX8450-B39-QR
Brand: Nexperia USA Inc.
SKU: BZX8450-B39-QR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: BZX8450-B39-QR

Manufacturer:: Nexperia USA Inc.

Category:: Single Zener Diodes

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

Datasheet:: BZX8450-B39-QR.pdf

Description:: DIODE ZENER 39V 250MW TO236AB

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:9,475

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

BZX8450-B39-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 39 V regulation at 50 µA test current, with ±2 % tolerance, 350 Ω dynamic resistance at 2 mA, and AEC-Q101 qualification for under-hood applications.

For engineers reviewing the BZX8450-B39-QR datasheet, BZX8450-B39-QR pinout, BZX8450-B39-QR application, or BZX8450-B39-QR equivalent, this page provides verified electrical parameters, thermal behavior, automotive-grade reliability data, and real-world use context for low-power voltage stabilization circuits.

Technical Context

This Zener diode operates in reverse breakdown mode with a specified working voltage of 38.2–39.8 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 differential resistance drops to 130 Ω at I_Z = 0.5 mA, supporting stable regulation under light-load conditions.

Designed for low-bias operation, it features intentional leakage optimization per AN90031 to reduce noise and improve switching response. The device sustains non-repetitive peak reverse power up to 40 W (100 µs pulse) and junction temperatures up to 150 °C, meeting automotive ambient requirements from −40 °C to +125 °C.

Key Specifications

Parameter	Value and Actual Design Meaning
Nominal Zener Voltage	39 V (min 38.2 V, max 39.8 V at I_Z = 50 µA - defines precise reference point for low-current bias networks)
Tolerance	±2 % (B-series grade - enables tighter voltage margin control vs. ±5 % C-series in critical analog references)
Differential Resistance	350 Ω at I_Z = 50 µA; 130 Ω at I_Z = 0.5 mA - determines output impedance and load regulation sensitivity)
Forward Voltage	≤ 0.9 V at I_F = 10 mA - ensures minimal forward conduction loss when used bidirectionally or in protection schemes)
Power Dissipation	250 mW at T_amb ≤ 25 °C on FR4 PCB - sets maximum continuous DC power handling without heatsinking)
Reverse Current	≤ 0.05 µA at V_R = 29.25 V - guarantees high impedance blocking below knee voltage in sensing or clamping paths)
Thermal Resistance	R_th(j-a) = 500 K/W (free air); R_th(j-sp) = 330 K/W (cathode solder point) - informs derating curves for PCB layout and thermal management)

Pinout & Package

SOT23 plastic surface-mount package (2.9 mm × 1.3 mm × 1.0 mm body, 1.9 mm pin pitch), optimized for automated assembly and space-constrained automotive modules.

Pin/Terminal	Circuit Role	Design Meaning
1	Anode (A)	Connects to lower-potential node in reverse-biased Zener configuration; must be held at voltage ≤ cathode minus V_Z for regulation
2	Not Connected (n.c.)	Internally unconnected terminal - must remain floating; no PCB trace or solder mask required
3	Cathode (K)	Connects to higher-potential node; carries full Zener current during regulation; serves as primary thermal path to PCB

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive under-hood use including temperature cycling, humidity, and mechanical shock per discrete semiconductor stress test standard
Low test current operation	Specified at 50 µA - enables direct battery monitoring and ultra-low-power sensor biasing without loading source
Optimized leakage profile	Intentional minor rise in leakage per AN90031 - reduces high-frequency noise and improves transient response in feedback loops
Two tolerance grades	B-series (±2 %) and C-series (≈±5 %) - allows cost/performance trade-off selection across reference, protection, and calibration functions
High-temperature stability	Junction rating up to 150 °C with SZ = +0.05 mV/K - maintains regulation accuracy across extended automotive operating range

Applications

Automotive Cabin Control Module

Portable Gas Detector Signal Conditioning

Use Scenario: Providing stable 39 V reference for microcontroller ADC input scaling in HVAC control units exposed to engine bay thermal transients.

IC Role / Device Role / Timing Role: Zener voltage reference diode - establishes fixed analog reference rail independent of supply fluctuations.

Use Value: Enables ±0.78 V absolute accuracy over −40 °C to +125 °C, reducing calibration drift and improving sensor linearity compensation.

Use Scenario: Biasing electrochemical gas sensor electrodes in handheld CO monitors powered by single-cell Li-ion batteries.

IC Role / Device Role / Timing Role: Low-current voltage regulator - supplies precise bias voltage while drawing <1 µA quiescent current in standby.

Use Value: Extends battery life beyond 2 years by minimizing idle current, while maintaining sensor sensitivity within ±2 % due to tight Zener tolerance.

Industrial PLC Input Protection

Medical Infusion Pump Power Monitoring

Use Scenario: Clamping 4–20 mA loop transients in programmable logic controller analog input stages subjected to ESD and inductive kickback.

IC Role / Device Role / Timing Role: Transient voltage suppressor - absorbs fast spikes up to 40 W (100 µs) without degradation.

Use Value: Prevents false triggering and ADC saturation during field wiring faults, meeting IEC 61000-4-2 Level 4 immunity requirements.

Use Scenario: Monitoring 36–42 V DC power rail integrity in battery-backed infusion pumps requiring fail-safe shutdown at undervoltage thresholds.

IC Role / Device Role / Timing Role: Precision undervoltage detection element - triggers comparator when rail drops below 38.2 V (Zener knee).

Use Value: Delivers sub-100 ms response to brownout events with zero external components, satisfying ISO 60601-1 safety-critical timing constraints.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BZX84-C39-Q	±5 % tolerance (vs. ±2 %), higher r_diff (375 Ω at 2 mA), same 39 V nominal, non-AEC-Q101	Acceptable for non-automotive industrial references where cost outweighs precision; unsuitable for AEC-compliant designs	Select only if budget constraints dominate and ±5 % regulation error is acceptable in final system tolerance stack-up
MMSZ4702T1G	39 V nominal, ±5 %, 500 mW P_tot, SOD-123 package, no AEC-Q101, r_diff = 120 Ω at 10 mA	Higher power capability but larger footprint; lacks automotive qualification and low-current optimization	Prefer for high-reliability non-automotive systems needing >250 mW dissipation, but avoid where SOT23 board space or AEC compliance is mandatory

Compared with BZX8450-B39-QR, the BZX84-C39-Q trades precision and qualification for cost, while MMSZ4702T1G offers higher power at the expense of automotive suitability and low-bias performance - making BZX8450-B39-QR uniquely suited for space-constrained, AEC-Q101–required 39 V reference nodes.

Availability

BZX8450-B39-QR is available at Aetrix Electronics and suitable for automotive cabin control modules, portable gas detectors, industrial PLC input protection, and medical infusion pump power monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BZX8450-B39-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 essential semiconductors for automotive, industrial, and consumer markets.

The BZX8450-Q series belongs to Nexperia's AEC-Q101–qualified Zener diode product line, engineered specifically for low-current voltage reference and regulation in harsh-environment automotive electronics.

FAQ

What is the maximum continuous reverse power dissipation for BZX8450-B39-QR at 85 °C ambient?

At T_amb = 85 °C, derating applies: P_tot = 250 mW × (1 − (85 − 25)/500) = 250 mW × 0.88 = 220 mW. This value assumes mounting on FR4 PCB with single-sided 70 µm copper and standard SOT23 footprint per datasheet condition [2]. Junction temperature remains within 150 °C limit.

Can BZX8450-B39-QR be used in forward conduction mode?

Yes - its forward voltage is specified ≤ 0.9 V at 10 mA, making it suitable for low-drop rectification or polarity protection. However, its primary design intent is reverse-bias Zener regulation; forward characteristics are secondary and not optimized for high-current switching.

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

Per AN90031, this controlled leakage reduces high-frequency noise and improves transient response in feedback paths by lowering effective junction capacitance modulation. It enhances stability in precision reference buffers and low-noise sensor front-ends without compromising DC accuracy.

Is pin 2 (n.c.) electrically isolated or internally tied to substrate?

Pin 2 is fully unconnected - no internal bond wire, die attachment, or metallization links it to anode, cathode, or substrate. It must remain un-soldered and un-traced on PCB; routing a trace to it risks mechanical stress or unintended coupling in high-frequency layouts.

BZX8450-B39-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):: 39 V

Tolerance:: ±2%

Power - Max:: 250 mW

Impedance (Max) (Zzt):: 130 Ohms

Current - Reverse Leakage @ Vr:: 50 nA @ 29.6 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-B39-QR FAQ

1.How can I place an order for BZX8450-B39-QR through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX8450-B39-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-B39-QR reliable?

The price and inventory of BZX8450-B39-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-B39-QR is usually 5 days.

3.What payment methods are accepted for BZX8450-B39-QR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX8450-B39-QR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX8450-B39-QR?

BZX8450-B39-QR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX8450-B39-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-B39-QR?

For technical support, including BZX8450-B39-QR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX8450-B39-QR requirements.

6.How does Aetrix verify that BZX8450-B39-QR is sourced from the original manufacturer or authorized distributors?

All BZX8450-B39-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-B39-QR meets industry standards.

7.What is the process for return or replacement of BZX8450-B39-QR?

All BZX8450-B39-QR units undergo pre-shipment inspection (PSI). If there is an issue with BZX8450-B39-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-B39-QR part is unused and in its original packaging.

Return procedure for BZX8450-B39-QR:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-03 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-01 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…