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

onsemi 1N5239B_T50A

Name: 1N5239B_T50A
Brand: onsemi
SKU: 1N5239B_T50A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N5239B_T50A

Manufacturer:: onsemi

Category:: Single Zener Diodes

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

Datasheet:: 1N5239B_T50A.pdf

Description:: DIODE ZENER 9.1V 500MW DO35

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Product details

Overview

1N5239B_T50A from ON Semiconductor is a 9.1 V, ±5% tolerance, 500 mW glass-encapsulated Zener diode in DO-35 package, designed for precision voltage regulation and reference applications in low-power analog circuits, power supply feedback loops, and overvoltage protection. It features 10 Ω dynamic impedance at 20 mA, 3.0 μA maximum reverse leakage at 7.0 V, and a temperature coefficient of +0.068 %/°C.

For engineers reviewing the 1N5239B_T50A datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal derating behavior, cathode identification, DO-35 mechanical dimensions, and validated alternative parts for voltage reference design and BOM optimization.

Technical Context

The 1N5239B_T50A operates as a two-terminal silicon Zener diode with sharp reverse breakdown at nominal 9.1 V, optimized for stable DC voltage reference under fixed-current bias. Its DO-35 hermetically sealed glass package ensures long-term parameter stability and low leakage across -65°C to +200°C junction temperature range.

It exhibits a positive temperature coefficient (+0.068 %/°C), indicating increasing Zener voltage with rising temperature - a key consideration when used in temperature-compensated references or ambient-varying environments. Power dissipation is rated at 500 mW at 25°C, derating linearly by 4.0 mW/°C above 50°C ambient.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	9.1 V nominal, min 8.645 V / max 9.555 V at I_Z = 20 mA - defines precise regulation point for feedback or clamping
Power Dissipation (P_D)	500 mW at T_A = 25°C - sets maximum continuous DC power handling before thermal shutdown risk
Zener Impedance (Z_Z)	10 Ω at I_Z = 20 mA - indicates low AC impedance for stable regulation under small-signal load variation
Reverse Leakage (I_R)	3.0 μA max at V_R = 7.0 V - ensures minimal current draw in standby or high-impedance bias networks
Temperature Coefficient (TC)	+0.068 %/°C - quantifies V_Z drift per degree Celsius; critical for temperature-sensitive references
Package	DO-35 glass axial - provides hermetic sealing, 0.137 g mass, and JEDEC-compliant mechanical footprint
Forward Voltage (V_F)	1.2 V max at I_F = 200 mA - defines conduction threshold when used in forward-biased protection or logic-level clamping

Pinout & Package

DO-35 glass axial package: hermetically sealed, 2.0 mm diameter body, 5.2 mm length, cathode identified by color band. Lead spacing ≥25.4 mm (T50), lead diameter 0.46 mm, weight 0.137 g.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / Zener cathode reference ground	Connected to lower-potential node in reverse-bias regulation; serves as return path for Zener current
Cathode	Zener breakdown terminal / voltage reference output	Marked with color band; connected to regulated voltage node; supplies stable 9.1 V when reverse-biased above knee

Key Features

Feature	Design Value
Precision voltage reference	±5% tolerance at 9.1 V enables accurate feedback in 12 V supply regulators and sensor excitation circuits
Low dynamic impedance	10 Ω at 20 mA ensures minimal output voltage shift under ±1 mA load transients
Stable temperature coefficient	+0.068 %/°C allows predictable V_Z drift modeling in industrial temperature ranges (-40°C to +85°C)
Hermetic glass packaging	DO-35 construction prevents moisture ingress and parameter drift over 10+ year deployments
Standardized axial form factor	Compatible with automated through-hole insertion and wave soldering per JEDEC DO-204AH

Applications

Power Supply Feedback	Overvoltage Clamp
Use Scenario: Regulating output of a 12 V linear regulator using TL431-based shunt feedback. IC Role / Device Role / Timing Role: Provides stable 9.1 V reference to set upper trip point for error amplifier comparison. Use Value: Enables ±1% output accuracy over line/load/temperature with no external trimming required.	Use Scenario: Protecting microcontroller I/O pins from transient surges on 5 V bus lines. IC Role / Device Role / Timing Role: Acts as passive clamp, conducting only when bus exceeds 9.1 V + diode drop. Use Value: Limits peak voltage to <10.5 V during ESD events without loading normal 5 V operation.
Sensor Excitation Reference	ADC Input Protection
Use Scenario: Biasing resistive bridge sensors (e.g., strain gauges) requiring stable excitation voltage. IC Role / Device Role / Timing Role: Supplies low-noise, temperature-stable 9.1 V excitation source independent of supply rail variation. Use Value: Reduces measurement drift to <0.05%/°C in precision weigh-scale front-ends.	Use Scenario: Preventing damage to 10-bit SAR ADC inputs during hot-plug or signal fault conditions. IC Role / Device Role / Timing Role: Shunts excess input voltage above 9.1 V to ground before reaching ADC ESD diodes. Use Value: Extends ADC lifetime by limiting input stress to safe operating area defined in datasheet.

Power Supply Feedback

Overvoltage Clamp

Use Scenario: Regulating output of a 12 V linear regulator using TL431-based shunt feedback.

IC Role / Device Role / Timing Role: Provides stable 9.1 V reference to set upper trip point for error amplifier comparison.

Use Value: Enables ±1% output accuracy over line/load/temperature with no external trimming required.

Use Scenario: Protecting microcontroller I/O pins from transient surges on 5 V bus lines.

IC Role / Device Role / Timing Role: Acts as passive clamp, conducting only when bus exceeds 9.1 V + diode drop.

Use Value: Limits peak voltage to <10.5 V during ESD events without loading normal 5 V operation.

Sensor Excitation Reference

ADC Input Protection

Use Scenario: Biasing resistive bridge sensors (e.g., strain gauges) requiring stable excitation voltage.

IC Role / Device Role / Timing Role: Supplies low-noise, temperature-stable 9.1 V excitation source independent of supply rail variation.

Use Value: Reduces measurement drift to <0.05%/°C in precision weigh-scale front-ends.

Use Scenario: Preventing damage to 10-bit SAR ADC inputs during hot-plug or signal fault conditions.

IC Role / Device Role / Timing Role: Shunts excess input voltage above 9.1 V to ground before reaching ADC ESD diodes.

Use Value: Extends ADC lifetime by limiting input stress to safe operating area defined in datasheet.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4739A	Same 9.1 V nominal rating but ±5% tolerance, 1 W power rating, DO-41 package	Higher power handling supports >100 mA regulation; larger DO-41 footprint requires PCB layout change	Select when higher surge energy absorption or longer thermal time constant is required
BZX55C9V1	9.1 V, ±5%, 500 mW, DO-35, but tighter Z_Z = 10 Ω typ (vs. 10 Ω max), lower I_R = 1.0 μA @ 7 V	Improved leakage and typical impedance support ultra-low-power IoT sensor nodes	Select when sub-μA standby current or tighter regulation consistency is prioritized

Compared with 1N4739A and BZX55C9V1, the 1N5239B_T50A offers identical voltage rating and package compatibility with legacy DO-35 designs, while balancing cost-effectiveness and proven reliability in industrial control and instrumentation BOMs.

Availability

1N5239B_T50A is available at Aetrix Electronics and suitable for power supply feedback, overvoltage protection, sensor excitation, and ADC input protection requiring stable component supply and long-lifecycle continuity.

Supply support for 1N5239B_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

ON Semiconductor is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and edge applications.

The 1N52xxB series is part of ON Semiconductor's legacy Zener diode portfolio, engineered for general-purpose voltage regulation and reference in cost-sensitive, high-reliability analog circuits.

FAQ

What is the Zener voltage tolerance of the 1N5239B_T50A?

The 1N5239B_T50A has a Zener voltage tolerance of ±5% at 9.1 V, meaning its actual breakdown voltage falls between 8.645 V and 9.555 V when tested at 20 mA. This tolerance is guaranteed per ON Semiconductor's 1N5221B–1N5263B datasheet Rev. 3, and applies across the full operating temperature range of -65°C to +200°C junction temperature.

Does the 1N5239B_T50A have a specified forward voltage?

Yes, the 1N5239B_T50A specifies a maximum forward voltage of 1.2 V at 200 mA forward current. This value is relevant when the device is used in forward-conduction mode for clamping or protection, and confirms compatibility with standard silicon diode drive requirements in mixed-signal interface circuits.

What is the thermal derating behavior of the 1N5239B_T50A above 50°C?

The 1N5239B_T50A derates linearly at 4.0 mW/°C above an ambient temperature of 50°C. At 75°C ambient, its usable power dissipation drops to 400 mW (500 mW − [25 × 4.0 mW]). This derating ensures safe junction temperature operation up to +200°C and must be applied in thermal design calculations for enclosed or high-temperature environments.

How is the cathode identified on the 1N5239B_T50A package?

The cathode of the 1N5239B_T50A is marked by a distinct color band on the DO-35 glass body - consistent with industry-standard polarity marking. The band aligns with the cathode terminal, which must be held at higher potential than the anode to achieve Zener breakdown and regulation. This marking is visible under standard visual inspection and compatible with automated optical recognition systems.

Is the 1N5239B_T50A suitable for use in precision voltage reference circuits?

The 1N5239B_T50A supports precision reference use in non-critical applications due to its ±5% tolerance, +0.068 %/°C temperature coefficient, and 10 Ω dynamic impedance. For higher precision, it is typically paired with trimming resistors or used in temperature-compensated configurations; standalone use achieves ~±1% system-level accuracy in well-designed feedback paths.

1N5239B_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):: 9.1 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 10 Ohms

Current - Reverse Leakage @ Vr:: 3 µA @ 7 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

1N5239B_T50A FAQ

1.How can I place an order for 1N5239B_T50A through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N5239B_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 1N5239B_T50A reliable?

The price and inventory of 1N5239B_T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5239B_T50A is usually 5 days.

3.What payment methods are accepted for 1N5239B_T50A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5239B_T50A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N5239B_T50A?

1N5239B_T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N5239B_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 1N5239B_T50A?

For technical support, including 1N5239B_T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5239B_T50A requirements.

6.How does Aetrix verify that 1N5239B_T50A is sourced from the original manufacturer or authorized distributors?

All 1N5239B_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 1N5239B_T50A meets industry standards.

7.What is the process for return or replacement of 1N5239B_T50A?

All 1N5239B_T50A units undergo pre-shipment inspection (PSI). If there is an issue with 1N5239B_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 1N5239B_T50A part is unused and in its original packaging.

Return procedure for 1N5239B_T50A:

1.Submit a request within 90 days.

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

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