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

onsemi 1N5259B_T50A

Name: 1N5259B_T50A
Brand: onsemi
SKU: 1N5259B_T50A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N5259B_T50A

Manufacturer:: onsemi

Category:: Single Zener Diodes

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

Datasheet:: 1N5259B_T50A.pdf

Description:: DIODE ZENER 39V 500MW DO35

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Product details

Overview

1N5259B_T50A from ON Semiconductor is a 39 V, ±5% tolerance, 500 mW glass-passivated 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 delivers 3.2 Ω dynamic impedance at 12 mA and exhibits a +0.094 %/°C temperature coefficient.

For engineers reviewing the 1N5259B_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include its stable 39 V Zener voltage at 12 mA, low leakage (<0.1 μA at 31.2 V), DO-35 mechanical compatibility, and thermal stability across -65°C to +200°C junction range.

Technical Context

This device operates as a two-terminal silicon Zener diode with sharp reverse-breakdown characteristics, optimized for operation in the Zener breakdown region under controlled current conditions. Its glass-passivated junction ensures long-term stability and low parameter drift, while the DO-35 hermetically sealed package supports high-reliability industrial and automotive environments.

The 1N5259B_T50A is specified for nominal 39 V regulation at I_Z = 12 mA, with dynamic impedance (Z_Z) of 80 Ω max at that current and knee impedance (Z_ZK) of 700 Ω max at I_ZK = 0.25 mA. Its forward voltage is ≤1.2 V at 200 mA, confirming standard silicon PN junction behavior.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	39 V min / 40.95 V max at I_Z = 12 mA - defines precise regulation point for feedback and reference circuits
Power Dissipation (P_D)	500 mW at T_A = 25°C - sets maximum continuous DC power handling in free-air conditions
Dynamic Impedance (Z_Z)	80 Ω max at I_Z = 12 mA - determines output voltage variation under load current changes
Temperature Coefficient (TC)	+0.094 %/°C - quantifies V_Z drift per degree Celsius, critical for temperature-sensitive references
Reverse Leakage (I_R)	≤0.1 μA at V_R = 31.2 V - ensures minimal error current in high-impedance bias networks
Junction Temperature Range	-65°C to +200°C - enables operation in extreme ambient or self-heating conditions without derating loss

Pinout & Package

DO-35 glass axial package: hermetically sealed, cathode indicated by color band, 0.137 g mass, JEDEC-compliant dimensions (body Ø1.53–1.91 mm, length 4.56 mm, lead spacing ≥25.4 mm).

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / Zener cathode reference ground	Connected to circuit ground or lower-potential node in shunt regulator configuration
Cathode	Reverse-biased Zener terminal / regulated output node	Connected to input via series resistor; provides stable 39 V reference relative to anode

Key Features

Feature	Design Value
±5% Zener voltage tolerance	Enables use without post-manufacturing trimming in cost-sensitive voltage reference designs
Glass-passivated junction	Provides superior long-term parameter stability and resistance to humidity-induced degradation
Low dynamic impedance (80 Ω)	Minimizes output voltage deviation under varying load currents in shunt regulation
High junction temperature rating (+200°C)	Supports reliable operation in thermally constrained enclosures or high-ambient environments
Hermetic DO-35 packaging	Ensures robustness against mechanical stress and environmental contaminants in industrial PCBs

Applications

Power Supply Feedback Reference	Overvoltage Clamp Protection
Use Scenario: Used in the optocoupler feedback path of isolated AC/DC flyback converters to regulate output voltage. IC Role / Device Role / Timing Role: Zener diode provides precise 39 V reference to control TL431 or optocoupler LED current. Use Value: Tight 5% tolerance and low TC ensure <±1% output regulation accuracy across temperature and line variations.	Use Scenario: Placed across sensitive IC inputs (e.g., microcontroller ADC reference) to limit transient overvoltage. IC Role / Device Role / Timing Role: Acts as passive shunt clamp, diverting excess energy to ground when voltage exceeds 39 V. Use Value: Low leakage (<0.1 μA) prevents signal loading during normal operation; fast Zener response limits spike amplitude.
Low-Power Analog Voltage Reference	Current Source Biasing
Use Scenario: Supplies stable bias to op-amp input stages or sensor excitation circuits in battery-powered instrumentation. IC Role / Device Role / Timing Role: Provides fixed 39 V reference for generating scaled-down precision voltages via resistive dividers. Use Value: Glass passivation and DO-35 hermeticity maintain reference stability over 10+ years in field-deployed equipment.	Use Scenario: Sets constant current through LEDs or photodiodes using a series resistor and 1N5259B_T50A as voltage reference. IC Role / Device Role / Timing Role: Establishes stable voltage drop across current-setting resistor to define I_LED = (V_Z − V_F)/R. Use Value: 80 Ω Z_Z ensures current remains within ±2% over ±10% input voltage variation at 12 mA operating point.

Power Supply Feedback Reference

Overvoltage Clamp Protection

Use Scenario: Used in the optocoupler feedback path of isolated AC/DC flyback converters to regulate output voltage.

IC Role / Device Role / Timing Role: Zener diode provides precise 39 V reference to control TL431 or optocoupler LED current.

Use Value: Tight 5% tolerance and low TC ensure <±1% output regulation accuracy across temperature and line variations.

Use Scenario: Placed across sensitive IC inputs (e.g., microcontroller ADC reference) to limit transient overvoltage.

IC Role / Device Role / Timing Role: Acts as passive shunt clamp, diverting excess energy to ground when voltage exceeds 39 V.

Use Value: Low leakage (<0.1 μA) prevents signal loading during normal operation; fast Zener response limits spike amplitude.

Low-Power Analog Voltage Reference

Current Source Biasing

Use Scenario: Supplies stable bias to op-amp input stages or sensor excitation circuits in battery-powered instrumentation.

IC Role / Device Role / Timing Role: Provides fixed 39 V reference for generating scaled-down precision voltages via resistive dividers.

Use Value: Glass passivation and DO-35 hermeticity maintain reference stability over 10+ years in field-deployed equipment.

Use Scenario: Sets constant current through LEDs or photodiodes using a series resistor and 1N5259B_T50A as voltage reference.

IC Role / Device Role / Timing Role: Establishes stable voltage drop across current-setting resistor to define I_LED = (V_Z − V_F)/R.

Use Value: 80 Ω Z_Z ensures current remains within ±2% over ±10% input voltage variation at 12 mA operating point.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N5259BRLG	Same electrical specs; tape-and-reel packaging (T50A = bulk, RL = reel); identical DO-35 package and marking	No functional difference; reel format preferred for automated SMT assembly	Select 1N5259BRLG for pick-and-place production; 1N5259B_T50A suits manual prototyping or low-volume repair
BZX55-C39	39 V, ±5%, 500 mW, but higher Z_Z (100 Ω typ), different DO-35 variant with alternate marking and slightly wider V_Z spread	Lower regulation precision due to higher impedance; less suitable for tight-tolerance feedback	Use BZX55-C39 only where cost is primary constraint and ±2% regulation is acceptable

Compared with 1N5259B_T50A, 1N5259BRLG offers identical performance in reel format for volume manufacturing, while BZX55-C39 trades tighter regulation for broader vendor availability but requires design margin for higher Z_Z and looser V_Z consistency.

Availability

1N5259B_T50A is available at Aetrix Electronics and suitable for power supply feedback reference, overvoltage clamp protection, and low-power analog voltage reference applications requiring stable component supply and long-lifecycle support.

Supply support for 1N5259B_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 manufacturer specializing in energy-efficient power, analog, sensor, and logic solutions for automotive, industrial, cloud computing, and consumer markets.

The 1N52xxB series is part of ON Semiconductor's legacy Zener diode portfolio, engineered for high-reliability voltage regulation in space-constrained, thermally demanding applications where stability and longevity are critical.

FAQ

What is the Zener voltage tolerance of the 1N5259B_T50A?

The 1N5259B_T50A has a Zener voltage tolerance of ±5% at I_Z = 12 mA, meaning its rated 39 V breakdown falls between 37.05 V and 40.95 V under standard test conditions. This tolerance is guaranteed per ON Semiconductor's 1N5221B–1N5263B datasheet Rev. 3, and applies to all units marked "1N5259B" regardless of packaging suffix like _T50A.

Does the 1N5259B_T50A have a specified forward voltage?

Yes, the 1N5259B_T50A has a maximum forward voltage of 1.2 V at I_F = 200 mA, as confirmed in the Absolute Maximum Ratings section of the official ON Semiconductor datasheet. This value reflects standard silicon diode conduction behavior and is relevant for polarity-checking or forward-bias applications, though the device is primarily used in reverse-biased Zener mode.

What is the maximum power dissipation for the 1N5259B_T50A at elevated temperatures?

The 1N5259B_T50A is rated for 500 mW at T_A = 25°C, with a linear derating factor of 4.0 mW/°C above 50°C. Therefore, at 75°C ambient, its maximum allowable power drops to 400 mW (500 − [4.0 × (75 − 50)]). This derating ensures safe junction temperature operation up to +200°C, as specified in the Absolute Maximum Ratings table.

Is the 1N5259B_T50A compatible with lead-free soldering processes?

Yes, the 1N5259B_T50A's DO-35 glass package supports lead-free reflow and wave soldering, with a maximum lead temperature of +230°C for 10 seconds (as specified in the Absolute Maximum Ratings). Its glass passivation and hermetic seal prevent moisture ingress and intermetallic formation, making it suitable for RoHS-compliant assembly without preconditioning.

How does the temperature coefficient affect the 1N5259B_T50A's performance in precision circuits?

The 1N5259B_T50A has a positive temperature coefficient of +0.094 %/°C, meaning its Zener voltage increases by approximately 36.7 mV per °C rise at 39 V. In precision reference designs, this drift must be compensated via circuit topology (e.g., combining with negative-TC components) or operating near 25°C to hold regulation error within ±0.5% over a 10°C span - a key consideration when selecting the 1N5259B_T50A for metrology-grade applications.

1N5259B_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):: 39 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 80 Ohms

Current - Reverse Leakage @ Vr:: 100 nA @ 30 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

1N5259B_T50A FAQ

1.How can I place an order for 1N5259B_T50A through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N5259B_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 1N5259B_T50A reliable?

The price and inventory of 1N5259B_T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5259B_T50A is usually 5 days.

3.What payment methods are accepted for 1N5259B_T50A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5259B_T50A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N5259B_T50A?

1N5259B_T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N5259B_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 1N5259B_T50A?

For technical support, including 1N5259B_T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5259B_T50A requirements.

6.How does Aetrix verify that 1N5259B_T50A is sourced from the original manufacturer or authorized distributors?

All 1N5259B_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 1N5259B_T50A meets industry standards.

7.What is the process for return or replacement of 1N5259B_T50A?

All 1N5259B_T50A units undergo pre-shipment inspection (PSI). If there is an issue with 1N5259B_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 1N5259B_T50A part is unused and in its original packaging.

Return procedure for 1N5259B_T50A:

1.Submit a request within 90 days.

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

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