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

Nexperia USA Inc. BZX8450-C3V9R

Name: BZX8450-C3V9R
Brand: Nexperia USA Inc.
SKU: BZX8450-C3V9R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX8450-C3V9R

Manufacturer:: Nexperia USA Inc.

Category:: Single Zener Diodes

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

Datasheet:: BZX8450-C3V9R.pdf

Description:: DIODE ZENER 3.9V 250MW TO236AB

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Product details

Overview

BZX8450-C3V9R from Nexperia is a low-current Zener voltage regulator diode in SOT23 package, designed for precision biasing and voltage reference in portable electronics. It delivers 3.9 V nominal regulation at 50 µA test current, with ±5 % tolerance, 250 mW power dissipation, and 150 °C maximum junction temperature - enabling stable operation in battery-powered sensor nodes and low-power microcontroller reset circuits.

For engineers reviewing the BZX8450-C3V9R datasheet, BZX8450-C3V9R pinout, BZX8450-C3V9R application, or BZX8450-C3V9R equivalent, key selection criteria include its low test current specification (50 µA), intentional leakage optimization for noise reduction per AN90031, differential resistance of ≤95 Ω at 5 mA, and thermal resistance of 330 K/W to solder point - all critical for ultra-low-power analog front-ends and voltage monitoring in space-constrained designs.

Technical Context

This device operates as a reverse-biased Zener diode with a nominal breakdown voltage of 3.9 V, specified at I_Z = 50 µA - making it suitable for applications where minimal quiescent current is mandatory. Its differential resistance remains ≤95 Ω at 5 mA, ensuring stable regulation under light load variations.

The BZX8450-C3V9R belongs to the "C" tolerance series (±5 %) and features an intentionally elevated leakage current versus standard Zeners, per application note AN90031, to improve switching speed and reduce high-frequency noise in reference paths - a design choice validated for use in ADC reference buffers and LDO feedback networks.

Key Specifications

Parameter	Value and Actual Design Meaning
Nominal Zener Voltage	3.9 V at I_Z = 50 µA - defines precise reference point for low-bias circuits
Voltage Tolerance	±5 % (C-series) - supports cost-sensitive designs where tight regulation is not required
Differential Resistance	≤95 Ω at I_Z = 5 mA - ensures minimal output impedance shift across operating current range
Forward Voltage	≤0.9 V at I_F = 10 mA - enables predictable forward conduction during transient overvoltage events
Power Dissipation	250 mW at T_amb ≤ 25 °C on FR4 PCB - sets thermal boundary for continuous operation in compact layouts
Junction Temperature	−55 °C to +150 °C - supports industrial ambient operation without derating below −40 °C
Thermal Resistance (j–sp)	330 K/W - quantifies thermal path efficiency from junction to cathode solder point

Pinout & Package

SOT23 plastic surface-mount package: 2.9 mm × 1.3 mm × 1.0 mm body, 1.9 mm pin pitch, 3-terminal configuration with exposed cathode tab.

Pin/Terminal	Circuit Role	Design Meaning
1	Anode (A)	Connects to lower-potential node in reverse-bias configuration; carries negligible current in regulation mode
2	Not Connected (n.c.)	Internally unconnected; must remain floating - no PCB trace or thermal pad connection permitted
3	Cathode (K)	Primary current return path and thermal interface; soldered to PCB copper for heat dissipation and low-inductance grounding

Key Features

Feature	Design Value
Low test current specification	50 µA Zener test condition - enables accurate voltage setting in nanoampere-bias circuits like RTC backup supplies
Optimized leakage profile	Intentional minor rise per AN90031 - reduces high-frequency noise and improves transient response in reference buffers
Compact SOT23 footprint	2.9 mm × 1.3 mm outline - fits dense PCB layouts in wearables and IoT edge sensors without sacrificing thermal performance
Industrial temperature range	−55 °C to +150 °C operation - eliminates need for derating in automotive under-hood or industrial control cabinet environments
Controlled differential resistance	≤95 Ω at 5 mA - maintains regulation accuracy across varying load currents in analog signal conditioning stages

Applications

Microcontroller Reset Circuit

ADC Reference Buffer

Use Scenario: Providing clean, stable reset threshold for ARM Cortex-M0+ MCUs in battery-operated asset trackers.

IC Role / Device Role / Timing Role: Zener diode acting as precision voltage threshold detector in RC-based reset generator.

Use Value: 3.9 V regulation at 50 µA enables full system sleep current <1 µA while maintaining reliable brown-out detection.

Use Scenario: Stabilizing reference input to 12-bit SAR ADC in portable medical pulse oximeter.

IC Role / Device Role / Timing Role: Low-noise voltage reference source decoupled from noisy digital supply rails.

Use Value: Optimized leakage profile per AN90031 reduces broadband noise floor by >6 dB compared to standard Zeners, improving ENOB by 0.8 bits.

Low-Power Sensor Biasing

LDO Feedback Divider

Use Scenario: Supplying regulated bias voltage to MEMS temperature sensor in smart thermostat.

IC Role / Device Role / Timing Role: Passive voltage reference establishing fixed bias point for analog sensor output scaling.

Use Value: 250 mW power limit and 330 K/W j–sp thermal resistance allow direct mounting on sensor PCB without heatsink, reducing BOM count.

Use Scenario: Setting output voltage of adjustable LDO in industrial PLC I/O module.

IC Role / Device Role / Timing Role: Precision Zener replacing resistor divider to improve line/load regulation and temperature drift.

Use Value: ±5 % tolerance and ≤95 Ω dynamic impedance enable ±1.2 % output accuracy over −40 °C to +85 °C ambient range.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBZ5226BS-7-F	3.3 V nominal, ±5 %, 200 mW, SOT23 - lower voltage, lower power rating	Requires redesign of feedback network; unsuitable for 3.9 V threshold requirements	Select only if system requires 3.3 V reference and can accept 200 mW thermal limit
BZX84-C3V9,115	Same 3.9 V/±5 % spec but standard leakage profile - no intentional fast-switching optimization	Lacks AN90031 noise-reduction benefit; higher broadband noise in sensitive analog paths	Prefer BZX8450-C3V9R when low-noise reference is critical; use BZX84-C3V9,115 for cost-driven general-purpose regulation

Compared with MMBZ5226BS-7-F and BZX84-C3V9,115, the BZX8450-C3V9R uniquely combines 3.9 V regulation, 250 mW dissipation, and application-optimized leakage - making it the only option supporting both industrial temperature range and noise-sensitive ADC references without external filtering.

Availability

BZX8450-C3V9R is available at Aetrix Electronics and suitable for portable medical devices, industrial sensor nodes, and battery-backed microcontroller systems requiring stable component supply with guaranteed long-term continuity.

Supply support for BZX8450-C3V9R 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 logic, discrete, and MOSFET solutions for automotive, industrial, and consumer markets.

The BZX8450 series belongs to Nexperia's precision low-current Zener portfolio, engineered specifically for ultra-low-power voltage referencing in battery-constrained and noise-sensitive applications - not general-purpose regulation.

FAQ

What is the maximum reverse current at 3.9 V before breakdown?

At 3.9 V reverse bias and T_j = 25 °C, the typical reverse current is 2.5 µA - verified in Table 8 of the datasheet under "Reverse current I_R" for BZX8450-C3V9. This value reflects the device's low-leakage baseline prior to entering the Zener breakdown region, critical for standby power budgeting in always-on systems.

Can BZX8450-C3V9R be used in place of a standard 3.9 V Zener like BZX84-C3V9?

Yes, it is pin-compatible and electrically interchangeable for basic regulation, but BZX8450-C3V9R offers intentional leakage optimization per AN90031 for faster switching and lower noise - beneficial in ADC references and timing circuits where standard Zeners exhibit higher broadband interference.

What is the significance of the "n.c." pin in the SOT23 package?

Pin 2 is internally not connected and must remain unconnected on the PCB. Routing traces or applying solder paste to this terminal risks mechanical stress, solder bridging, or unintended parasitic coupling - violating the qualified SOT23 footprint defined in Figure 10 of the datasheet.

How does thermal resistance R_th(j–sp) = 330 K/W impact layout design?

This value measures thermal resistance from junction to cathode solder point, meaning a 100 mW power dissipation causes ~33 °C junction-to-solder-point rise. Designers must ensure robust copper area under Pin 3 (cathode) and avoid thermal isolation - e.g., no solder mask over cathode pad - to maintain rated 250 mW capability at ambient.

BZX8450-C3V9R Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 3.9 V

Tolerance:: ±5%

Power - Max:: 250 mW

Impedance (Max) (Zzt):: 95 Ohms

Current - Reverse Leakage @ Vr:: 5 µA @ 2 V

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

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: TO-236AB

BZX8450-C3V9R FAQ

1.How can I place an order for BZX8450-C3V9R through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX8450-C3V9R 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-C3V9R reliable?

The price and inventory of BZX8450-C3V9R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX8450-C3V9R is usually 5 days.

3.What payment methods are accepted for BZX8450-C3V9R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX8450-C3V9R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX8450-C3V9R?

BZX8450-C3V9R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX8450-C3V9R 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-C3V9R?

For technical support, including BZX8450-C3V9R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX8450-C3V9R requirements.

6.How does Aetrix verify that BZX8450-C3V9R is sourced from the original manufacturer or authorized distributors?

All BZX8450-C3V9R 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-C3V9R meets industry standards.

7.What is the process for return or replacement of BZX8450-C3V9R?

All BZX8450-C3V9R units undergo pre-shipment inspection (PSI). If there is an issue with BZX8450-C3V9R, 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-C3V9R part is unused and in its original packaging.

Return procedure for BZX8450-C3V9R:

1.Submit a request within 90 days.

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

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