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

onsemi 1N5229B_T26A

Name: 1N5229B_T26A
Brand: onsemi
SKU: 1N5229B_T26A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N5229B_T26A

Manufacturer:: onsemi

Category:: Single Zener Diodes

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

Datasheet:: 1N5229B_T26A.pdf

Description:: DIODE ZENER 4.3V 500MW DO35

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Product details

Overview

1N5229B_T26A from ON Semiconductor is a 4.3 V ±5% Zener diode in DO-35 glass package, rated for 500 mW power dissipation at 25°C, with 22 Ω dynamic impedance at 20 mA test current and 5.0 μA maximum reverse leakage at 3.4 V. It serves as a precision voltage reference or overvoltage clamp in low-power analog signal conditioning circuits.

For engineers reviewing the 1N5229B_T26A datasheet, pinout, applications, or equivalent options, this page delivers verified Zener voltage tolerance, thermal derating behavior, cathode identification marking, junction temperature limits, and direct replacement options for legacy Fairchild-designated 1N5229B variants.

Technical Context

This device operates in reverse-biased Zener breakdown mode to maintain stable voltage regulation across load and line variations. Its 4.3 V nominal Zener voltage is specified at I_Z = 20 mA with ±5% tolerance and a temperature coefficient of ±0.055 %/°C, indicating near-zero drift near room temperature.

The DO-35 hermetically sealed glass package ensures long-term stability and low leakage, supporting operation from −65°C to +200°C junction temperature. Thermal derating begins above 50°C at 4.0 mW/°C, limiting usable power in high-ambient environments without heatsinking.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	4.3 V nominal at I_Z = 20 mA - defines regulated output voltage under standard test conditions
Zener Tolerance	±5% - sets absolute voltage accuracy band (4.085 V to 4.515 V) for production binning
Dynamic Impedance (Z_Z)	22 Ω at I_Z = 20 mA - determines regulation sensitivity to current changes; lower value improves line/load regulation
Power Dissipation (P_D)	500 mW at T_A = 25°C - maximum steady-state power before thermal runaway; derates linearly above 50°C
Reverse Leakage (I_R)	5.0 μA max at V_R = 3.4 V - quantifies off-state conduction; critical for low-power bias networks
Temperature Coefficient	±0.055 %/°C - indicates minimal V_Z drift near 25°C; enables stable references in unheated enclosures

Pinout & Package

DO-35 glass axial package with cathode identified by a single color band; total length 4.56 mm, body diameter 1.91 mm, lead diameter 0.46 mm, and weight 0.137 g. Hermetically sealed per JEDEC DO-204AH.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / Zener cathode reference node	Connected to lower-potential side in Zener regulator; forms return path for reverse current
Cathode	Zener breakdown terminal / voltage reference output	Marked with color band; connected to higher-potential side; provides stable 4.3 V reference when reverse-biased

Key Features

Feature	Design Value
±5% Zener voltage tolerance	Enables use in applications requiring tighter regulation than general-purpose Zeners (e.g., sensor biasing, ADC reference trimming)
DO-35 hermetic glass package	Provides superior long-term parameter stability and moisture resistance versus plastic-packaged alternatives
−65°C to +200°C operating range	Supports deployment in automotive engine compartments, industrial controllers, and aerospace subsystems
Low 5.0 μA leakage at 3.4 V	Minimizes quiescent current draw in battery-powered voltage monitor circuits

Applications

Instrumentation Reference	Power Supply Clamp
Use Scenario: Providing stable bias voltage for op-amp input stages in portable multimeters and data loggers. IC Role / Device Role / Timing Role: Precision DC voltage reference source for analog front-end circuitry. Use Value: ±5% tolerance and low TC ensure measurement accuracy remains within spec across temperature without calibration.	Use Scenario: Clamping transient overvoltage on 5 V logic rails during ESD events or switching noise coupling. IC Role / Device Role / Timing Role: Shunt protection element that conducts above 4.515 V to limit rail excursion. Use Value: 22 Ω Z_Z enables fast clamping response; DO-35 package withstands repeated surge pulses without degradation.
Sensor Excitation	Microcontroller Reset Circuit
Use Scenario: Supplying excitation current to resistive temperature detectors (RTDs) in HVAC control modules. IC Role / Device Role / Timing Role: Constant-voltage current source via series resistor, leveraging stable V_Z. Use Value: Low 5.0 μA leakage preserves current accuracy; wide T_J range supports outdoor-rated enclosures.	Use Scenario: Generating clean reset threshold for 3.3 V microcontrollers during brown-out conditions. IC Role / Device Role / Timing Role: Voltage detection node feeding comparator or integrated reset controller. Use Value: Tight 4.3 V ±5% window aligns precisely with common MCU reset thresholds, reducing false triggers.

Instrumentation Reference

Power Supply Clamp

Use Scenario: Providing stable bias voltage for op-amp input stages in portable multimeters and data loggers.

IC Role / Device Role / Timing Role: Precision DC voltage reference source for analog front-end circuitry.

Use Value: ±5% tolerance and low TC ensure measurement accuracy remains within spec across temperature without calibration.

Use Scenario: Clamping transient overvoltage on 5 V logic rails during ESD events or switching noise coupling.

IC Role / Device Role / Timing Role: Shunt protection element that conducts above 4.515 V to limit rail excursion.

Use Value: 22 Ω Z_Z enables fast clamping response; DO-35 package withstands repeated surge pulses without degradation.

Sensor Excitation

Microcontroller Reset Circuit

Use Scenario: Supplying excitation current to resistive temperature detectors (RTDs) in HVAC control modules.

IC Role / Device Role / Timing Role: Constant-voltage current source via series resistor, leveraging stable V_Z.

Use Value: Low 5.0 μA leakage preserves current accuracy; wide T_J range supports outdoor-rated enclosures.

Use Scenario: Generating clean reset threshold for 3.3 V microcontrollers during brown-out conditions.

IC Role / Device Role / Timing Role: Voltage detection node feeding comparator or integrated reset controller.

Use Value: Tight 4.3 V ±5% window aligns precisely with common MCU reset thresholds, reducing false triggers.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4733A	5.1 V nominal, 5% tolerance, 1 W rating in DO-41 package	Higher power and voltage; unsuitable for space-constrained 4.3 V reference designs	Select only if system requires 5.1 V regulation and board layout accommodates larger DO-41 footprint
BZX55-C4V3	4.3 V ±5%, 500 mW, DO-35, but with 30 Ω Z_Z and 10 μA I_R at 3.4 V	Higher impedance and leakage reduce regulation precision in low-current bias networks	Acceptable for non-critical clamping where tighter V_Z stability is not required

Compared with 1N4733A and BZX55-C4V3, the 1N5229B_T26A offers optimal balance of 4.3 V targeting, low 22 Ω impedance, and sub-μA leakage-making it preferred for precision analog references where DO-35 form factor is mandated.

Availability

1N5229B_T26A is available at Aetrix Electronics and suitable for instrumentation reference, power supply clamp, sensor excitation, and microcontroller reset circuits requiring stable component supply and long-lifecycle availability.

Supply support for 1N5229B_T26A 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The 1N52xxB series belongs to ON Semiconductor's legacy Zener diode product line, designed specifically for cost-sensitive, high-reliability voltage reference and protection applications in compact through-hole assemblies.

FAQ

What is the exact Zener voltage range for 1N5229B_T26A?

The 1N5229B_T26A has a nominal Zener voltage of 4.3 V with ±5% tolerance, resulting in a guaranteed range of 4.085 V to 4.515 V when tested at I_Z = 20 mA and T_A = 25°C. This range is confirmed in the ON Semiconductor 1N5221B–1N5263B datasheet Rev. 3, December 2018, Table "Electrical Characteristics".

Does 1N5229B_T26A have a cathode marking, and how is it identified?

Yes, the 1N5229B_T26A uses a single color band on the DO-35 glass body to denote the cathode terminal. This marking follows JEDEC DO-204AH standards and is visible as a distinct band near one end of the cylindrical package. The anode is the unmarked lead.

What is the maximum power dissipation for 1N5229B_T26A at 70°C ambient?

At 70°C ambient, the 1N5229B_T26A must be derated from its 500 mW rating at 25°C. Derating starts at 50°C at 4.0 mW/°C, so at 70°C the allowable power is 500 mW − (20°C × 4.0 mW/°C) = 420 mW. This ensures safe junction temperature below +200°C.

Is 1N5229B_T26A suitable for use in automotive under-hood applications?

Yes, the 1N5229B_T26A supports junction temperatures from −65°C to +200°C and uses a hermetically sealed DO-35 glass package, making it suitable for under-hood automotive applications such as engine control module voltage monitoring-provided board-level thermal design maintains T_J within limits.

How does the temperature coefficient of 1N5229B_T26A affect its performance in wide-temperature environments?

The 1N5229B_T26A has a temperature coefficient of ±0.055 %/°C near 25°C, meaning its Zener voltage drifts less than ±0.237 mV/°C around nominal. This low drift supports stable reference performance in industrial environments where ambient varies from −40°C to +85°C without active compensation.

1N5229B_T26A 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):: 4.3 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 22 Ohms

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

Voltage - Forward (Vf) (Max) @ If:: 1.2 V @ 200 mA

Operating Temperature:: -65°C ~ 200°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-35

1N5229B_T26A FAQ

1.How can I place an order for 1N5229B_T26A through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N5229B_T26A 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 1N5229B_T26A reliable?

The price and inventory of 1N5229B_T26A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5229B_T26A is usually 5 days.

3.What payment methods are accepted for 1N5229B_T26A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5229B_T26A transactions.

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4.How is shipping managed for 1N5229B_T26A?

1N5229B_T26A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N5229B_T26A 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 1N5229B_T26A?

For technical support, including 1N5229B_T26A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5229B_T26A requirements.

6.How does Aetrix verify that 1N5229B_T26A is sourced from the original manufacturer or authorized distributors?

All 1N5229B_T26A 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 1N5229B_T26A meets industry standards.

7.What is the process for return or replacement of 1N5229B_T26A?

All 1N5229B_T26A units undergo pre-shipment inspection (PSI). If there is an issue with 1N5229B_T26A, 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 1N5229B_T26A part is unused and in its original packaging.

Return procedure for 1N5229B_T26A:

1.Submit a request within 90 days.

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

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