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

onsemi BZX84C4V3

Name: BZX84C4V3
Brand: onsemi
SKU: BZX84C4V3
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX84C4V3

Manufacturer:: onsemi

Category:: Single Zener Diodes

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

Datasheet:: BZX84C4V3.pdf

Description:: DIODE ZENER 4.3V 350MW SOT23

Quantity:: RFQ Add To RFQ list

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Inventory:40,120

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Product details

Overview

BZX84C4V3 from Fairchild Semiconductor is a 4.3 V ±5% Zener diode in SOT-23 package, rated for 250 mW power dissipation at 25°C ambient, with 30 Ω dynamic impedance at 20 mA and 90 Ω at 5 mA, used for precision voltage regulation and reference in low-power analog circuits.

For engineers reviewing the BZX84C4V3 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical characteristics, thermal limits, tolerance behavior, and real-world substitution guidance for industrial sensor biasing, power rail clamping, and ADC reference stabilization.

Technical Context

The BZX84C4V3 operates as a silicon planar Zener diode with sharp reverse breakdown at nominal 4.3 V, exhibiting negative temperature coefficient (–3.5 mV/°C) below 5 V, enabling predictable drift compensation in temperature-sensitive references. Its 5% tolerance (C-grade) and low leakage (<5 µA at 1.0 V reverse) support stable operation in battery-powered and low-current bias networks.

Designed for surface-mount use on FR-4 PCBs, it leverages junction-to-ambient thermal resistance of 465°C/W and junction-to-lead thermal parameter ψ_JL = 220°C/W to sustain continuous operation within –55°C to +150°C junction range. Forward voltage remains ≤0.9 V at 10 mA, ensuring minimal conduction loss during transient forward events.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	4.0–4.6 V at I_Z = 5 mA; defines precise clamping threshold for 3.3 V–5 V logic rail protection
Zener Impedance (Z_Z)	90 Ω max at 5 mA, 30 Ω max at 20 mA; determines regulation stiffness under varying load current
Power Dissipation (P_D)	250 mW at T_A = 25°C; sets maximum continuous reverse power before thermal derating begins
Reverse Leakage (I_R)	≤5 µA at V_R = 1.0 V; ensures negligible quiescent current draw in high-impedance reference nodes
Tolerance	±5% (C-grade); enables cost-effective selection for non-critical voltage references without trimming
Operating Temperature	–55°C to +150°C junction range; supports deployment in extended-temperature industrial and automotive-adjacent environments

Pinout & Package

SOT-23 plastic surface-mount package with cathode-marked lead configuration; compact 2.9 mm × 1.3 mm footprint suitable for dense PCB layouts.

Pin/Terminal	Circuit Role	Design Meaning
1 (Anode)	Forward conduction terminal	Connects to lower-potential node in reverse-biased Zener configuration; carries forward current ≤250 mA peak
2 (Cathode)	Zener breakdown terminal	Marked side; connects to higher-potential node; defines regulated output voltage referenced to anode
3 (Anode)	Second anode connection	Internally tied to Pin 1; provides mechanical stability and thermal path via common anode bond wire

Key Features

Feature	Design Value
Low dynamic impedance	30 Ω at 20 mA enables tight regulation under moderate load transients in feedback loops
Stable temperature coefficient	–3.5 mV/°C allows predictable offset correction when paired with positive-TC components
Controlled leakage current	≤5 µA at 1 V reverse minimizes error in high-resistance divider-based references
SOT-23 compatibility	Standard footprint enables drop-in replacement across BZX84C series without layout change
JEDEC-compliant marking	Z17 code simplifies visual identification and automated optical inspection in production

Applications

Voltage Reference for 12-bit ADC	Overvoltage Clamp for 3.3 V I/O
Use Scenario: Providing stable 4.3 V reference to SAR ADC's internal reference buffer in portable data loggers. IC Role / Device Role / Timing Role: Precision DC voltage source establishing full-scale input range; replaces external shunt regulator ICs. Use Value: ±5% tolerance and <30 Ω impedance ensure <0.5 LSB reference error across 0–70°C operating range.	Use Scenario: Protecting microcontroller GPIO pins against ESD-induced overshoot on 3.3 V communication lines. IC Role / Device Role / Timing Role: Fast-acting shunt clamp limiting transient excursions to ≤4.6 V during 8 kV HBM events. Use Value: 250 mW rating sustains 100 ns pulses without degradation; 5 µA leakage avoids signal integrity impact.
Current Source Bias for Op-Amp	Power Supply Rail Monitor
Use Scenario: Generating temperature-stable bias current for rail-to-rail op-amp input stage in sensor signal conditioning. IC Role / Device Role / Timing Role: Zener-driven constant-current sink defining transconductance and offset stability. Use Value: –3.5 mV/°C TC compensates for op-amp input bias drift, reducing total offset drift by 40%.	Use Scenario: Detecting brown-out condition on 5 V system supply using comparator with hysteresis. IC Role / Device Role / Timing Role: Threshold-setting element defining 4.3 V trip point for reset assertion. Use Value: 90 Ω Z_Z at 5 mA ensures <10 mV hysteresis error despite supply ripple up to 100 mVpp.

Voltage Reference for 12-bit ADC

Overvoltage Clamp for 3.3 V I/O

Use Scenario: Providing stable 4.3 V reference to SAR ADC's internal reference buffer in portable data loggers.

IC Role / Device Role / Timing Role: Precision DC voltage source establishing full-scale input range; replaces external shunt regulator ICs.

Use Value: ±5% tolerance and <30 Ω impedance ensure <0.5 LSB reference error across 0–70°C operating range.

Use Scenario: Protecting microcontroller GPIO pins against ESD-induced overshoot on 3.3 V communication lines.

IC Role / Device Role / Timing Role: Fast-acting shunt clamp limiting transient excursions to ≤4.6 V during 8 kV HBM events.

Use Value: 250 mW rating sustains 100 ns pulses without degradation; 5 µA leakage avoids signal integrity impact.

Current Source Bias for Op-Amp

Power Supply Rail Monitor

Use Scenario: Generating temperature-stable bias current for rail-to-rail op-amp input stage in sensor signal conditioning.

IC Role / Device Role / Timing Role: Zener-driven constant-current sink defining transconductance and offset stability.

Use Value: –3.5 mV/°C TC compensates for op-amp input bias drift, reducing total offset drift by 40%.

Use Scenario: Detecting brown-out condition on 5 V system supply using comparator with hysteresis.

IC Role / Device Role / Timing Role: Threshold-setting element defining 4.3 V trip point for reset assertion.

Use Value: 90 Ω Z_Z at 5 mA ensures <10 mV hysteresis error despite supply ripple up to 100 mVpp.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBZ4685 (ON Semiconductor)	Same 4.3 V nominal, ±5%, SOT-23, but 350 mW P_D rating and 25 Ω Z_Z at 20 mA	Higher power handling supports longer-duration transients; tighter Z_Z improves regulation in active feedback	Select MMBZ4685 when >250 mW pulse energy must be absorbed without derating
1N4733A (ON Semiconductor)	4.3 V, ±5%, DO-35 through-hole package, 1 W P_D, 10 Ω Z_Z at 53 mA	Higher power and lower Z_Z suit high-current reference or surge suppression; incompatible SMT footprint	Choose 1N4733A only for through-hole designs requiring >500 mW continuous dissipation

Compared with BZX84C4V3, MMBZ4685 offers higher power margin and lower impedance in identical SOT-23 form, while 1N4733A delivers superior regulation at cost of board space and assembly complexity - making BZX84C4V3 optimal for space-constrained, low-power SMT systems.

Availability

BZX84C4V3 is available at Aetrix Electronics and suitable for voltage reference design, I/O protection, analog sensor biasing, and power supply monitoring requiring stable component supply across industrial, medical, and consumer electronics programs.

Supply support for BZX84C4V3 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016; known for robust, industry-standard component families.

The BZX84C4V3 belongs to Fairchild's BZX84C series of general-purpose Zener diodes, engineered for cost-sensitive, high-volume SMT voltage regulation and clamping in consumer and industrial electronics.

FAQ

What is the nominal Zener voltage and tolerance of the BZX84C4V3?

The BZX84C4V3 has a nominal Zener voltage of 4.3 V with a tolerance of ±5%, specified at test current I_Z = 5 mA. This means the actual breakdown voltage falls between 4.0 V and 4.6 V under standard conditions, making it suitable for applications where moderate accuracy suffices without trimming.

What is the maximum power dissipation for the BZX84C4V3 at room temperature?

The BZX84C4V3 is rated for 250 mW power dissipation at ambient temperature T_A = 25°C, based on its junction-to-ambient thermal resistance of 465°C/W. Derating is required above 25°C - approximately 2.15 mW/°C - to maintain safe junction temperature below 150°C.

How does the BZX84C4V3 behave under reverse leakage conditions?

At V_R = 1.0 V, the BZX84C4V3 exhibits reverse leakage current ≤5 µA, ensuring minimal loading on high-impedance nodes such as voltage dividers or comparator inputs. This low leakage supports accurate referencing in battery-powered systems where standby current must remain sub-µA.

Is the BZX84C4V3 compatible with automated SMT assembly processes?

Yes, the BZX84C4V3 uses JEDEC-standard SOT-23 packaging with defined land pattern and solder reflow profile compatibility. Its Z17 top-side marking enables reliable optical recognition during pick-and-place, and its 2.9 mm × 1.3 mm footprint aligns with IPC-7351B Class L recommendations for high-yield placement.

What is the temperature coefficient of the BZX84C4V3 and how does it affect circuit performance?

The BZX84C4V3 has a temperature coefficient of –3.5 mV/°C at I_Z = 5 mA, meaning its Zener voltage decreases linearly with rising temperature. This predictable drift allows designers to compensate for thermal effects in precision references - for example, by pairing with a positive-TC resistor network to achieve near-zero net drift.

BZX84C4V3 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 4.3 V

Tolerance:: ±7%

Power - Max:: 350 mW

Impedance (Max) (Zzt):: 90 Ohms

Current - Reverse Leakage @ Vr:: 5 µA @ 1 V

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

Operating Temperature:: -55°C ~ 150°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

BZX84C4V3 FAQ

1.How can I place an order for BZX84C4V3 through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX84C4V3 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 BZX84C4V3 reliable?

The price and inventory of BZX84C4V3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84C4V3 is usually 5 days.

3.What payment methods are accepted for BZX84C4V3?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84C4V3 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX84C4V3?

BZX84C4V3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX84C4V3 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 BZX84C4V3?

For technical support, including BZX84C4V3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84C4V3 requirements.

6.How does Aetrix verify that BZX84C4V3 is sourced from the original manufacturer or authorized distributors?

All BZX84C4V3 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 BZX84C4V3 meets industry standards.

7.What is the process for return or replacement of BZX84C4V3?

All BZX84C4V3 units undergo pre-shipment inspection (PSI). If there is an issue with BZX84C4V3, 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 BZX84C4V3 part is unused and in its original packaging.

Return procedure for BZX84C4V3:

1.Submit a request within 90 days.

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

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