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

onsemi 1N747A_T50A

Name: 1N747A_T50A
Brand: onsemi
SKU: 1N747A_T50A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N747A_T50A

Manufacturer:: onsemi

Category:: Single Zener Diodes

Package:: DO-204AH, DO-35, Axial

Datasheet:: 1N747A_T50A.pdf

Description:: DIODE ZENER 3.6V 500MW DO35

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Product details

Overview

1N747A_T50A from Fairchild Semiconductor is a 3.6 V ±5% silicon Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C, with 24 Ω dynamic impedance at 20 mA test current and 10 µA reverse leakage at 1 V reverse voltage. It provides precise low-voltage regulation in voltage reference and overvoltage protection circuits.

For engineers reviewing the 1N747A_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal derating behavior, cathode identification via band marking, and compatibility with lead-forming constraints for through-hole PCB assembly.

Technical Context

This device operates as a two-terminal voltage reference diode, relying on controlled reverse-biased avalanche breakdown. Its 3.6 V nominal zener voltage is specified at 20 mA test current with ±5% tolerance, and its 24 Ω dynamic impedance ensures stable regulation under moderate load variation.

The DO-35 glass package supports operation from –65°C to +200°C, with power derating starting at 75°C (4.0 mW/°C), and cathode polarity is unambiguously marked by a single color band on the case per JEDEC standards.

Key Specifications

Parameter	Value and Actual Design Meaning
V_Z @ I_Z = 20 mA	3.6 V nominal, ±5% tolerance - defines regulated output voltage under standard test condition
Z_Z @ I_Z = 20 mA	24 Ω - indicates small-signal AC resistance affecting regulation stability under varying load
P_D @ T_L ≤ 75°C	500 mW - maximum steady-state power handling with 3/8″ lead length, critical for thermal layout
I_R @ V_R = 1 V	10 µA - reverse leakage magnitude defining minimum bias current needed before breakdown
T_J/T_STG	–65°C to +200°C - wide operating/storage range enabling use in automotive under-hood and industrial environments
Package	DO-35 glass - axial-leaded, hermetically sealed, cathode identified by single color band

Pinout & Package

DO-35 glass axial package with cathode identified by a single color band; anode and cathode terminals are unidirectional, non-reversible, and require correct orientation during PCB insertion.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward current entry / Reverse breakdown reference node	Connected to lower-potential side in regulation circuit; determines forward conduction direction
Cathode	Reverse breakdown terminal / Voltage reference output	Marked by color band; connected to higher-potential side to establish regulated V_Z drop

Key Features

Feature	Design Value
±5% V_Z tolerance	Enables predictable voltage clamping without post-assembly trimming in cost-sensitive analog references
DO-35 glass construction	Provides hermetic sealing and long-term parameter stability under thermal cycling and humidity exposure
500 mW power rating	Supports direct replacement of legacy 1/2 W Zeners without heatsinking in low-power supply rails
Cathode band marking	Ensures unambiguous polarity identification during manual or automated assembly per JEDEC DO-35 standard

Applications

Voltage Reference for Analog Sensors	Overvoltage Clamp in Microcontroller I/O Protection
Use Scenario: Providing stable 3.6 V bias to temperature or pressure sensor signal conditioning circuits. IC Role / Device Role / Timing Role: Zener diode acting as shunt voltage reference, absorbing excess current to maintain fixed node voltage. Use Value: Delivers ±5% accuracy without external trimming, reducing BOM count versus precision IC references.	Use Scenario: Protecting 3.3 V GPIO pins from ESD transients or supply rail overshoot. IC Role / Device Role / Timing Role: Shunt clamp limiting voltage to 3.6 V, diverting surge current away from sensitive input structures. Use Value: Leverages 24 Ω Z_Z to limit clamping voltage rise under transient current, improving protection margin.
Low-Power Power Supply Regulation	Feedback Node Stabilization in Linear Regulators
Use Scenario: Regulating auxiliary 3.6 V rail for logic-level interface circuitry in battery-powered devices. IC Role / Device Role / Timing Role: Passive shunt regulator maintaining constant output voltage across variable load current up to 100 mA. Use Value: Uses 500 mW rating to sustain regulation without active pass element, simplifying design and reducing quiescent current.	Use Scenario: Stabilizing feedback divider node in adjustable LDOs to improve line/load regulation accuracy. IC Role / Device Role / Timing Role: Low-impedance voltage reference point minimizing noise injection into error amplifier input. Use Value: 24 Ω Z_Z reduces sensitivity to divider resistor tolerance and layout parasitics.

Voltage Reference for Analog Sensors

Overvoltage Clamp in Microcontroller I/O Protection

Use Scenario: Providing stable 3.6 V bias to temperature or pressure sensor signal conditioning circuits.

IC Role / Device Role / Timing Role: Zener diode acting as shunt voltage reference, absorbing excess current to maintain fixed node voltage.

Use Value: Delivers ±5% accuracy without external trimming, reducing BOM count versus precision IC references.

Use Scenario: Protecting 3.3 V GPIO pins from ESD transients or supply rail overshoot.

IC Role / Device Role / Timing Role: Shunt clamp limiting voltage to 3.6 V, diverting surge current away from sensitive input structures.

Use Value: Leverages 24 Ω Z_Z to limit clamping voltage rise under transient current, improving protection margin.

Low-Power Power Supply Regulation

Feedback Node Stabilization in Linear Regulators

Use Scenario: Regulating auxiliary 3.6 V rail for logic-level interface circuitry in battery-powered devices.

IC Role / Device Role / Timing Role: Passive shunt regulator maintaining constant output voltage across variable load current up to 100 mA.

Use Value: Uses 500 mW rating to sustain regulation without active pass element, simplifying design and reducing quiescent current.

Use Scenario: Stabilizing feedback divider node in adjustable LDOs to improve line/load regulation accuracy.

IC Role / Device Role / Timing Role: Low-impedance voltage reference point minimizing noise injection into error amplifier input.

Use Value: 24 Ω Z_Z reduces sensitivity to divider resistor tolerance and layout parasitics.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4729A	3.6 V nominal, same ±5% tolerance, but 50 Ω Z_Z and 1.0 W power rating in DO-41 package	Higher power handling and larger footprint; less suitable for space-constrained DO-35 layouts	Select when higher surge current capability or board-level thermal mass is available
BZX55-C3V6	3.6 V nominal, ±5% tolerance, 90 Ω Z_Z, 500 mW rating in DO-35, but tighter IR spec (≤1 µA @ 1 V)	Lower leakage enables ultra-low-power standby circuits; slightly degraded regulation stiffness	Select when sub-microamp reverse leakage is required, e.g., in energy-harvesting systems

Compared with 1N4729A and BZX55-C3V6, the 1N747A_T50A offers optimal balance of regulation stiffness (24 Ω Z_Z), compact DO-35 form factor, and proven thermal performance across –65°C to +200°C - making it preferred for high-reliability, space-limited analog reference nodes.

Availability

1N747A_T50A is available at Aetrix Electronics and suitable for voltage reference, overvoltage protection, and low-power regulation applications requiring stable component supply, consistent parametric performance, and long-term manufacturability assurance.

Supply support for 1N747A_T50A 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 components before its acquisition by ON Semiconductor in 2016.

The 1N747A_T50A belongs to Fairchild's legacy 1N7xxA Zener diode family, designed for general-purpose voltage regulation and clamping in industrial, consumer, and computing power systems.

FAQ

What is the exact zener voltage tolerance for 1N747A_T50A?

The 1N747A_T50A has a zener voltage tolerance of ±5% at 20 mA test current, meaning its actual V_Z falls between 3.42 V and 3.78 V under standard conditions. This tolerance is guaranteed across the full operating temperature range and is measured with the device junction at thermal equilibrium at 30°C ±1°C lead temperature.

Does 1N747A_T50A have a specified forward voltage?

Yes - the 1N747A_T50A specifies a maximum forward voltage (V_F) of 1.5 V at 200 mA forward current. This value is relevant for applications where the diode may conduct in forward bias, such as during power-up sequencing or fault conditions, and confirms compatibility with standard silicon diode drive levels.

How is cathode polarity identified on the 1N747A_T50A package?

The cathode of the 1N747A_T50A is marked by a single color band on the DO-35 glass body, consistent with JEDEC DO-35 packaging standards. This band must be oriented toward the higher-potential side of the circuit to ensure proper reverse-bias operation and accurate zener voltage establishment.

What is the maximum allowable junction temperature for 1N747A_T50A?

The 1N747A_T50A supports an operating junction temperature range of –65°C to +200°C. Its power dissipation must be derated linearly above 75°C at 4.0 mW/°C, based on 3/8″ lead length, to prevent exceeding the absolute maximum junction temperature limit.

Can 1N747A_T50A replace older 1N747 variants without design changes?

Yes - the 1N747A_T50A maintains identical electrical specifications, DO-35 package dimensions, and marking convention as earlier revisions of the 1N747 series. No PCB layout or schematic modifications are required when upgrading from non-A suffix versions, provided the same thermal and current constraints apply.

1N747A_T50A Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: DO-204AH, DO-35, Axial

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Voltage - Zener (Nom) (Vz):: 3.6 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 24 Ohms

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

Voltage - Forward (Vf) (Max) @ If:: 1.5 V @ 200 mA

Operating Temperature:: -65°C ~ 200°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-35

1N747A_T50A FAQ

1.How can I place an order for 1N747A_T50A through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N747A_T50A 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 1N747A_T50A reliable?

The price and inventory of 1N747A_T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N747A_T50A is usually 5 days.

3.What payment methods are accepted for 1N747A_T50A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N747A_T50A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N747A_T50A?

1N747A_T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N747A_T50A 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 1N747A_T50A?

For technical support, including 1N747A_T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N747A_T50A requirements.

6.How does Aetrix verify that 1N747A_T50A is sourced from the original manufacturer or authorized distributors?

All 1N747A_T50A 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 1N747A_T50A meets industry standards.

7.What is the process for return or replacement of 1N747A_T50A?

All 1N747A_T50A units undergo pre-shipment inspection (PSI). If there is an issue with 1N747A_T50A, 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 1N747A_T50A part is unused and in its original packaging.

Return procedure for 1N747A_T50A:

1.Submit a request within 90 days.

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

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