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

Nexperia USA Inc. BZX84W-B12X

Name: BZX84W-B12X
Brand: Nexperia USA Inc.
SKU: BZX84W-B12X
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX84W-B12X

Manufacturer:: Nexperia USA Inc.

Category:: Single Zener Diodes

Package:: SC-70, SOT-323

Datasheet:: BZX84W-B12X.pdf

Description:: DIODE ZENER 12V 275MW SOT323

Quantity:: RFQ Add To RFQ list

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Inventory:8,533

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Product details

Overview

BZX84W-B12X from Nexperia is a ±2 % tolerance Zener voltage regulator diode in SOT323 (SC-70) package, rated for 12 V nominal Zener voltage at 5 mA, 275 mW total power dissipation, and 150 °C maximum junction temperature. It provides precision voltage reference and regulation in low-power analog circuits, ESD protection clamping networks, and biasing stages of RF front-ends.

For engineers reviewing the BZX84W-B12X datasheet, BZX84W-B12X pinout, BZX84W-B12X application, or BZX84W-B12X equivalent, this page delivers verified Zener voltage, differential resistance, temperature coefficient, reverse leakage, and thermal resistance - all critical for stable reference design, transient suppression, and high-frequency signal path integrity.

Technical Context

This Zener diode operates in reverse breakdown with a specified nominal Zener voltage of 12 V at I_Z = 5 mA, differential resistance of 150 Ω (max), and temperature coefficient of +8.4 mV/K (typ). Its low 2.5 pF capacitance at 1 MHz and 0 V reverse bias supports use in high-frequency decoupling and RF detector circuits.

The device features a non-connected (n.c.) terminal (Pin 2), enabling layout flexibility in compact SMT designs. Its thermal resistance from junction to ambient is 455 K/W on standard FR4 PCB, defining safe continuous power handling under natural convection conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage V_Z	11.8 V to 12.2 V at I_Z = 5 mA - tight ±2 % tolerance enables accurate voltage reference without trimming.
Differential Resistance r_dif	150 Ω max at I_Z = 5 mA - low dynamic impedance ensures stable regulation under varying load current.
Temperature Coefficient S_Z	+8.4 mV/K typ at I_Z = 5 mA - predictable positive drift allows compensation in temperature-sensitive references.
Reverse Leakage I_R	100 nA max at V_R = 8 V - ultra-low leakage preserves accuracy in high-impedance bias networks.
Total Power Dissipation P_tot	275 mW at T_amb = 25 °C on FR4 PCB - defines maximum continuous DC or average pulsed power in standard mounting.
Junction-to-Ambient Thermal Resistance R_th(j-a)	455 K/W - quantifies self-heating rise per watt; used to calculate actual T_j in real board environments.
Diode Capacitance C_d	2.5 pF at f = 1 MHz, V_R = 0 V - minimal parasitic capacitance avoids signal distortion in >100 MHz applications.

Pinout & Package

SOT323 (SC-70) leadless surface-mount plastic package: 1.35 mm × 1.8 mm footprint, 0.65 mm pitch, 0.9 mm height, single-sided copper FR4 mounting.

Pin/Terminal	Circuit Role	Design Meaning
1	Anode (A)	Forward-biased terminal; connects to lower-potential node in Zener operation (reverse-biased cathode).
2	Not Connected (n.c.)	Internally unconnected; must be left floating or grounded per layout - no electrical function.
3	Cathode (K)	Reverse-biased terminal during regulation; connects to higher-potential node and load return path.

Key Features

Feature	Design Value
±2 % Zener voltage tolerance	Enables direct replacement in precision reference circuits without calibration or resistor adjustment.
2.5 pF junction capacitance	Minimizes loading on RF signal paths and preserves bandwidth in 50 Ω systems up to 500 MHz.
100 nA max reverse leakage at 8 V	Reduces error in high-impedance voltage dividers and extends battery life in always-on monitoring nodes.
Non-repetitive peak reverse power: 40 W (100 µs)	Supports robust ESD clamping per IEC 61000-4-2 Level 4 (±15 kV air) when properly routed.
SOT323 package with standard reflow footprint	Ensures compatibility with automated assembly lines using IPC-7351B-compliant land patterns.

Applications

Power Supply Reference

RF Signal Detector

Use Scenario: Providing stable 12 V reference for ADC voltage reference buffers and op-amp biasing in industrial sensor signal chains.

IC Role / Device Role / Timing Role: Zener voltage reference diode operating in reverse breakdown to generate fixed DC potential.

Use Value: ±2 % V_Z tolerance and +8.4 mV/K temperature coefficient allow predictable drift compensation across −40 °C to +85 °C ambient range.

Use Scenario: Peak-envelope detection in 2.4 GHz ISM-band receiver front-ends with minimal signal loss.

IC Role / Device Role / Timing Role: Low-capacitance Zener clamp converting RF envelope to baseband DC level.

Use Value: 2.5 pF capacitance and 150 Ω dynamic impedance preserve RF signal integrity while delivering fast, repeatable envelope response.

ESD Protection Clamp

Microcontroller Reset Circuit

Use Scenario: Secondary-level transient suppression on USB data lines adjacent to primary TVS devices.

IC Role / Device Role / Timing Role: Fast-reacting Zener clamp limiting voltage excursions to ≤13.5 V during ESD events.

Use Value: 40 W non-repetitive peak power rating enables reliable clamping of IEC 61000-4-2 contact discharge pulses without degradation.

Use Scenario: Generating clean, noise-immune reset signal for ARM Cortex-M0+ microcontrollers during brown-out conditions.

IC Role / Device Role / Timing Role: Precision Zener regulating reset threshold voltage independent of supply ripple.

Use Value: 100 nA reverse leakage prevents false resets caused by leakage-induced voltage droop on RC timing networks.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ON Semiconductor MMBZ5242B	Same 12 V ±5 % V_Z, but higher 22 Ω r_dif and 100 nA I_R at 8 V; SOT-23 package.	Larger footprint and higher thermal resistance (500 K/W); less suitable for space-constrained RF layouts.	Select when legacy SOT-23 compatibility is required and tighter tolerance is not critical.
Vishay BZX84-C12	12 V ±5 % V_Z, 220 Ω r_dif max, 100 nA I_R at 8 V; same SOT323 package.	Looser tolerance increases reference uncertainty; higher r_dif degrades load regulation performance.	Choose only for cost-sensitive, non-critical biasing where ±5 % V_Z is acceptable.

Compared with MMBZ5242B and BZX84-C12, BZX84W-B12X delivers superior voltage accuracy (±2 %), lower dynamic impedance (150 Ω), and identical SOT323 form factor - making it optimal for precision reference and high-frequency clamping where stability and size are jointly constrained.

Availability

BZX84W-B12X is available at Aetrix Electronics and suitable for industrial sensor interfaces, RF detector circuits, ESD protection networks, and microcontroller reset generation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BZX84W-B12X 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, serving automotive, industrial, and consumer markets with ISO/TS 16949-certified manufacturing.

The BZX84W series belongs to Nexperia's general-purpose Zener diode product line, engineered for stable voltage regulation and transient suppression in space-constrained, high-frequency SMT applications.

FAQ

What is the maximum continuous reverse current for BZX84W-B12X at 25 °C?

The device does not specify a maximum continuous reverse current; instead, its safe operating area is defined by total power dissipation (275 mW) and junction temperature limit (150 °C). At 12 V Zener voltage, this corresponds to a maximum average reverse current of approximately 22.9 mA under ideal thermal conditions on FR4 PCB.

Can BZX84W-B12X replace BZX84-C12 in existing designs?

Yes, with qualification: both share identical SOT323 package and 12 V nominal Zener voltage, but BZX84W-B12X offers ±2 % tolerance versus ±5 % for BZX84-C12. Layout and soldering remain compatible, though reference accuracy improves by 3 % absolute, potentially eliminating downstream calibration.

Is Pin 2 (n.c.) required to be grounded or left floating?

Pin 2 is internally not connected and must be left electrically floating. Grounding it introduces no benefit and risks unintended coupling or solder bridging; PCB layout should maintain clearance and avoid routing traces to this pad per Nexperia's recommended footprint.

How does the +8.4 mV/K temperature coefficient affect circuit performance?

This positive coefficient means V_Z increases by ~8.4 mV per Kelvin rise in junction temperature. In a 50 °C ambient-to-junction rise, V_Z shifts +420 mV - a known, linear drift that can be compensated in feedback loops or accepted where ±3.5 % variation is tolerable over full operating range.

BZX84W-B12X Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: BZX84W

Package/Case:: SC-70, SOT-323

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 12 V

Tolerance:: ±2%

Power - Max:: 275 mW

Impedance (Max) (Zzt):: 25 Ohms

Current - Reverse Leakage @ Vr:: 100 nA @ 8 V

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

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

BZX84W-B12X FAQ

1.How can I place an order for BZX84W-B12X through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX84W-B12X 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 BZX84W-B12X reliable?

The price and inventory of BZX84W-B12X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84W-B12X is usually 5 days.

3.What payment methods are accepted for BZX84W-B12X?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84W-B12X transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX84W-B12X?

BZX84W-B12X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX84W-B12X 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 BZX84W-B12X?

For technical support, including BZX84W-B12X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84W-B12X requirements.

6.How does Aetrix verify that BZX84W-B12X is sourced from the original manufacturer or authorized distributors?

All BZX84W-B12X 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 BZX84W-B12X meets industry standards.

7.What is the process for return or replacement of BZX84W-B12X?

All BZX84W-B12X units undergo pre-shipment inspection (PSI). If there is an issue with BZX84W-B12X, 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 BZX84W-B12X part is unused and in its original packaging.

Return procedure for BZX84W-B12X:

1.Submit a request within 90 days.

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

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