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

onsemi 1N4731ATR

Name: 1N4731ATR
Brand: onsemi
SKU: 1N4731ATR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N4731ATR

Manufacturer:: onsemi

Category:: Single Zener Diodes

Package:: DO-204AL, DO-41, Axial

Datasheet:: 1N4731ATR.pdf

Description:: DIODE ZENER 4.3V 1W DO41

Quantity:: RFQ Add To RFQ list

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Inventory:93,000

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Product details

Overview

1N4731ATR from Fairchild Semiconductor is a 4.3 V, 1 W Zener diode in DO-41 glass package, designed for precision voltage regulation and reference applications with ±5% tolerance, 58 Ω dynamic impedance at 9 mA test current, and 1 μA leakage at 3.4 V reverse bias. It operates across -65°C to +200°C and supports overvoltage protection in power supply feedback loops.

For engineers reviewing the 1N4731ATR datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage (4.3 V), power dissipation (1.0 W), Zener impedance (58 Ω), leakage current (1 μA @ 3.4 V), and DO-41 package compatibility with through-hole PCB layouts.

Technical Context

The 1N4731ATR functions as a two-terminal silicon Zener diode operating in reverse breakdown mode, maintaining stable voltage across its cathode-anode terminals under controlled current conditions. Its 4.3 V nominal Zener voltage is specified at 9 mA test current (IZ), with dynamic impedance measured at that same current point.

Thermal derating begins above 50°C at 6.67 mW/°C, and the device supports non-repetitive peak reverse surge currents up to 1070 mA (8.3 ms square wave). The DO-41 glass package provides hermetic sealing and standard lead-forming compatibility for industrial power regulation circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	4.3 V nominal, min 4.085 V / max 4.515 V at 9 mA - defines regulated output voltage in shunt regulator designs
Power Dissipation (P_D)	1.0 W @ T_L ≤ 50°C - sets maximum continuous power handling before thermal derating applies
Zener Impedance (Z_Z)	58 Ω @ I_Z = 9 mA - determines voltage regulation stability under load current variation
Leakage Current (I_R)	1 μA @ V_R = 3.4 V - ensures minimal standby current in low-power reference circuits
Operating Temperature	-65°C to +200°C - enables use in automotive under-hood, industrial control, and high-reliability environments
Tolerance	±5% - specifies allowable deviation of V_Z across production lots for predictable circuit design margins

Pinout & Package

DO-41 glass axial package with cathode indicated by a single color band on the body. Leads are tinned copper-clad steel, 0.40–0.50 mm diameter, 3/8″ length standard for thermal rating compliance.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / Reverse breakdown reference node	Connected to lower-potential side of regulated circuit; establishes reference ground path in shunt configuration
Cathode	Reverse-biased Zener terminal / Voltage regulation output node	Connected to higher-potential side; delivers stable 4.3 V reference when reverse current ≥ 9 mA

Key Features

Feature	Design Value
Stable Zener voltage at 9 mA	Ensures consistent regulation point across temperature and aging, critical for analog reference accuracy
Low dynamic impedance (58 Ω)	Minimizes output voltage shift under varying load currents, improving line and load regulation
Hermetic DO-41 glass package	Provides long-term reliability and moisture resistance in harsh environments without conformal coating
Wide operating temperature range	Supports deployment in engine control units, industrial PLCs, and outdoor power electronics

Applications

Power Supply Feedback	Overvoltage Protection
Use Scenario: Regulating output voltage in linear and switching power supplies via optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Zener reference element providing precise 4.3 V threshold to error amplifier input. Use Value: Enables tight output voltage tolerance (±1%) without external trimming components.	Use Scenario: Clamping transient surges on 5 V logic rails or sensor inputs during ESD or load dump events. IC Role / Device Role / Timing Role: Shunt protection device diverting excess energy to ground when voltage exceeds 4.3 V. Use Value: Limits peak voltage to safe levels for downstream CMOS ICs rated for 5.5 V absolute maximum.
Voltage Reference	Current Source Biasing
Use Scenario: Generating stable bias voltage for op-amp comparators, ADC references, or sensor excitation circuits. IC Role / Device Role / Timing Role: Precision DC reference source delivering 4.3 V with low temperature coefficient. Use Value: Reduces drift-induced measurement error in 12-bit data acquisition systems operating from -40°C to +85°C.	Use Scenario: Setting constant current for LED drivers or transistor bias networks using series resistor + Zener configuration. IC Role / Device Role / Timing Role: Voltage reference defining current setpoint via Ohm's Law (I = (V_IN − 4.3 V)/R). Use Value: Achieves ±5% current accuracy across input voltage variations from 6 V to 12 V.

Power Supply Feedback

Overvoltage Protection

Use Scenario: Regulating output voltage in linear and switching power supplies via optocoupler-coupled feedback loop.

IC Role / Device Role / Timing Role: Zener reference element providing precise 4.3 V threshold to error amplifier input.

Use Value: Enables tight output voltage tolerance (±1%) without external trimming components.

Use Scenario: Clamping transient surges on 5 V logic rails or sensor inputs during ESD or load dump events.

IC Role / Device Role / Timing Role: Shunt protection device diverting excess energy to ground when voltage exceeds 4.3 V.

Use Value: Limits peak voltage to safe levels for downstream CMOS ICs rated for 5.5 V absolute maximum.

Voltage Reference

Current Source Biasing

Use Scenario: Generating stable bias voltage for op-amp comparators, ADC references, or sensor excitation circuits.

IC Role / Device Role / Timing Role: Precision DC reference source delivering 4.3 V with low temperature coefficient.

Use Value: Reduces drift-induced measurement error in 12-bit data acquisition systems operating from -40°C to +85°C.

Use Scenario: Setting constant current for LED drivers or transistor bias networks using series resistor + Zener configuration.

IC Role / Device Role / Timing Role: Voltage reference defining current setpoint via Ohm's Law (I = (V_IN − 4.3 V)/R).

Use Value: Achieves ±5% current accuracy across input voltage variations from 6 V to 12 V.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4731A	Same electrical specs and DO-41 package; differs only in packaging format (ammo pack vs. tape/reel)	No functional difference; identical performance in all circuit roles	Select 1N4731A for manual assembly or small-batch prototyping where reel packaging is unnecessary
BZX55-C4V3	4.3 V Zener, ±5% tolerance, but in DO-35 glass package with 500 mW rating and 70 Ω Z_Z	Lower power handling limits use in >500 mW regulation or surge scenarios	Choose BZX55-C4V3 only when board space constraints require smaller DO-35 footprint and power demand is ≤ 0.5 W

Compared with 1N4731A and BZX55-C4V3, the 1N4731ATR offers full 1 W power capability in DO-41, making it optimal for robust industrial feedback and protection circuits where thermal margin and surge resilience are critical.

Availability

1N4731ATR is available at Aetrix Electronics and suitable for power supply feedback, overvoltage protection, and voltage reference applications requiring stable component supply, long-lifecycle availability, and traceable sourcing for industrial and automotive programs.

Supply support for 1N4731ATR 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.

The 1N4731ATR belongs to the legacy 1N47xxA Zener diode family, engineered for general-purpose voltage regulation and reference in cost-sensitive, high-reliability power electronics.

FAQ

What is the nominal Zener voltage and tolerance of the 1N4731ATR?

The 1N4731ATR has a nominal Zener voltage of 4.3 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 4.085 V and 4.515 V when tested at 9 mA. This specification is guaranteed across the full operating temperature range and is critical for designing accurate voltage references and regulation circuits using the 1N4731ATR.

What is the maximum power dissipation rating for the 1N4731ATR?

The 1N4731ATR is rated for 1.0 W power dissipation at lead temperature (T_L) ≤ 50°C, with linear derating of 6.67 mW/°C above that temperature. This rating assumes 3/8″ lead length and defines the upper limit of continuous reverse power the 1N4731ATR can safely handle without exceeding junction temperature limits.

What package type does the 1N4731ATR use, and how is polarity marked?

The 1N4731ATR uses the DO-41 glass axial package, with cathode polarity indicated by a single color band on the body. The anode and cathode leads are tinned copper-clad steel, and the marking conforms to Fairchild's top-marking standard: "47", "31", "A", and date code lines. This physical configuration ensures compatibility with standard through-hole assembly processes for the 1N4731ATR.

What is the Zener impedance of the 1N4731ATR, and why does it matter?

The 1N4731ATR exhibits a Zener impedance (Z_Z) of 58 Ω measured at the 9 mA test current. This value quantifies how much the output voltage changes with load current variation - lower Z_Z means tighter regulation. In practice, this allows the 1N4731ATR to maintain stable reference voltage in feedback loops where current may fluctuate, directly impacting system accuracy.

Can the 1N4731ATR be used in high-temperature environments like automotive under-hood applications?

Yes, the 1N4731ATR is rated for operation from -65°C to +200°C, making it suitable for under-hood automotive applications such as engine control unit voltage references and sensor biasing. Its DO-41 glass package maintains parameter stability across this range, and thermal derating guidelines ensure reliable performance even at elevated ambient temperatures - a key advantage of the 1N4731ATR in demanding environments.

1N4731ATR Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: DO-204AL, DO-41, Axial

Packaging:: Bulk

Product Status:: Active

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

Tolerance:: ±5%

Power - Max:: 1 W

Impedance (Max) (Zzt):: 9 Ohms

Current - Reverse Leakage @ Vr:: 10 µA @ 1 V

Voltage - Forward (Vf) (Max) @ If:: -

Operating Temperature:: -65°C ~ 200°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-41

1N4731ATR FAQ

1.How can I place an order for 1N4731ATR through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N4731ATR 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 1N4731ATR reliable?

The price and inventory of 1N4731ATR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4731ATR is usually 5 days.

3.What payment methods are accepted for 1N4731ATR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4731ATR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N4731ATR?

1N4731ATR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N4731ATR 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 1N4731ATR?

For technical support, including 1N4731ATR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4731ATR requirements.

6.How does Aetrix verify that 1N4731ATR is sourced from the original manufacturer or authorized distributors?

All 1N4731ATR 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 1N4731ATR meets industry standards.

7.What is the process for return or replacement of 1N4731ATR?

All 1N4731ATR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4731ATR, 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 1N4731ATR part is unused and in its original packaging.

Return procedure for 1N4731ATR:

1.Submit a request within 90 days.

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

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