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

onsemi 1N5349B

Name: 1N5349B
Brand: onsemi
SKU: 1N5349B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N5349B

Manufacturer:: onsemi

Category:: Single Zener Diodes

Package:: T-18, Axial

Datasheet:: 1N5349B.pdf

Description:: DIODE ZENER 12V 5W AXIAL

Quantity:: RFQ Add To RFQ list

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Inventory:9,848

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Product details

Overview

1N5349B from onsemi is a 5 W axial-lead Zener diode with nominal zener voltage of 12 V (±5%), maximum zener impedance of 100 Ω at 2.5 mA test current, and surge rating of 395 A at 8.3 ms - used for precision voltage regulation in power supply reference circuits, overvoltage protection clamps, and analog signal conditioning stages.

For engineers reviewing the 1N5349B datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal resistance (25 °C/W junction-to-lead), leakage current (0.25 mA at 9.1 V), and Pb-free axial package compatibility with wave soldering at 260 °C.

Technical Context

The 1N5349B operates as a silicon-oxide passivated junction Zener regulator, delivering stable reverse-biased breakdown at 12 V with temperature coefficient of +5.5 mV/°C (typical for 11–75 V range). Its design supports DC and pulsed regulation up to 150 °C junction temperature under continuous operation.

It features Class 3 ESD immunity (>16 kV HBM), 180 W non-repetitive surge capability, and tight parameter control across six electrical specs - including V_Z, I_ZM, Z_ZT, Z_ZK, I_ZK, and I_R - validated per JEDEC standards for ±5% tolerance devices.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	11.4 V min / 12.0 V nom / 12.6 V max @ I_ZT = 2.5 mA - defines regulated output voltage window under standard test conditions
Max Power Dissipation	5 W @ T_L = 25°C - sets absolute steady-state thermal limit before derating begins
Zener Impedance	100 Ω max @ I_ZT = 2.5 mA - determines regulation stiffness and AC ripple rejection capability
Leakage Current	0.25 mA max @ V_R = 9.1 V - specifies off-state conduction level below breakdown threshold
Surge Current	395 A peak @ 8.3 ms pulse - enables transient overvoltage suppression without failure
Junction-to-Lead R_θJL	25 °C/W - defines thermal path efficiency from die to lead; critical for PCB heatsinking design
ESD Rating	Class 3 (>16 kV) per HBM - ensures robustness during handling and board assembly

Pinout & Package

Package: Axial-lead, transfer-molded plastic (Case 017AA), cathode indicated by band. Dimensions: 8.38–8.89 mm length × 3.30–3.68 mm diameter; leads 25.4–31.75 mm long.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / low-side connection in reverse-bias regulation	Connected to circuit ground or lower potential node when used as shunt regulator
Cathode	Zener breakdown terminal / high-side connection in reverse-bias regulation	Connected to input voltage source; regulates voltage at cathode relative to anode

Key Features

Feature	Design Value
±5% Zener voltage tolerance	Guarantees tight regulation window (11.4–12.6 V) without post-manufacturing trimming
Silicon-oxide passivated junction	Enables stable long-term performance and low parameter drift under thermal cycling
Void-free thermosetting plastic case	Provides environmental sealing against moisture, dust, and chemical exposure
Pb-free compliant construction	Meets RoHS Directive 2011/65/EU and JEDEC J-STD-609A Class 3 marking requirements
260°C solderability rating	Supports industry-standard wave and reflow processes without delamination or bond degradation

Applications

Power Supply Reference	Overvoltage Clamp
Use Scenario: Stabilizing feedback voltage in linear regulator ICs or op-amp-based reference circuits. IC Role / Device Role / Timing Role: Shunt voltage reference providing precise 12 V bias point for error amplifiers. Use Value: Maintains ±1% output accuracy over temperature due to low 100 Ω dynamic impedance and +5.5 mV/°C TC.	Use Scenario: Protecting downstream logic inputs from transient surges exceeding 12 V. IC Role / Device Role / Timing Role: Clamping element diverting excess energy to ground during ESD or load-dump events. Use Value: Withstands 395 A surge at 8.3 ms without parametric shift, preserving system integrity.
Analog Signal Conditioning	Industrial Sensor Interface
Use Scenario: Biasing transducer bridges or setting mid-rail voltages in 24 V industrial analog front-ends. IC Role / Device Role / Timing Role: Precision DC level shifter establishing stable 12 V common-mode reference. Use Value: Low 0.25 mA leakage at 9.1 V prevents loading errors in high-impedance sensor nodes.	Use Scenario: Providing regulated excitation voltage to RTDs or strain gauges in PLC I/O modules. IC Role / Device Role / Timing Role: Primary voltage reference for ratiometric measurement systems requiring traceable stability. Use Value: Passivated junction ensures <0.5% V_Z drift after 1000 hrs at 125°C, meeting IEC 61000-4-2 immunity requirements.

Power Supply Reference

Overvoltage Clamp

Use Scenario: Stabilizing feedback voltage in linear regulator ICs or op-amp-based reference circuits.

IC Role / Device Role / Timing Role: Shunt voltage reference providing precise 12 V bias point for error amplifiers.

Use Value: Maintains ±1% output accuracy over temperature due to low 100 Ω dynamic impedance and +5.5 mV/°C TC.

Use Scenario: Protecting downstream logic inputs from transient surges exceeding 12 V.

IC Role / Device Role / Timing Role: Clamping element diverting excess energy to ground during ESD or load-dump events.

Use Value: Withstands 395 A surge at 8.3 ms without parametric shift, preserving system integrity.

Analog Signal Conditioning

Industrial Sensor Interface

Use Scenario: Biasing transducer bridges or setting mid-rail voltages in 24 V industrial analog front-ends.

IC Role / Device Role / Timing Role: Precision DC level shifter establishing stable 12 V common-mode reference.

Use Value: Low 0.25 mA leakage at 9.1 V prevents loading errors in high-impedance sensor nodes.

Use Scenario: Providing regulated excitation voltage to RTDs or strain gauges in PLC I/O modules.

IC Role / Device Role / Timing Role: Primary voltage reference for ratiometric measurement systems requiring traceable stability.

Use Value: Passivated junction ensures <0.5% V_Z drift after 1000 hrs at 125°C, meeting IEC 61000-4-2 immunity requirements.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4742A	12 V ±5%, 1 W rating, higher Z_ZT (22 Ω), TO-204AA metal can package	Limited to low-power references; lacks 395 A surge rating and Class 3 ESD	Select when cost-sensitive, low-current (<100 mA) designs require legacy metal-can form factor
BZX85C12	12 V ±5%, 1.3 W rating, 100 Ω Z_ZT, DO-41 plastic package, no surge rating specified	Not qualified for repetitive surge events; thermal resistance not characterized beyond 1.3 W	Choose for space-constrained PCBs where axial lead length must be minimized and surge immunity is secondary

Compared with 1N5349B, both alternatives offer matching 12 V regulation but lack its 5 W power handling, 395 A surge capability, and guaranteed six-parameter specification - making 1N5349B the only choice for industrial-grade 12 V shunt regulation requiring field reliability and thermal margin.

Availability

1N5349B is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and programmable logic controller (PLC) I/O conditioning requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.

Supply support for 1N5349B 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The 1N53 Series belongs to onsemi's Surmetic™ 40 Zener regulator family, engineered for high-reliability voltage reference and protection applications demanding tight tolerances, robust surge immunity, and extended temperature operation.

FAQ

What is the exact zener voltage tolerance and test condition for 1N5349B?

The 1N5349B has a ±5% zener voltage tolerance, verified at I_ZT = 2.5 mA with 40 ±10 ms current application time. Its nominal V_Z is 12.0 V, with minimum 11.4 V and maximum 12.6 V values guaranteed across production lots per JEDEC standards.

Can 1N5349B replace 1N4742A in a 5 W power supply reference design?

No - while both regulate at 12 V, the 1N5349B is rated for 5 W continuous dissipation versus 1 W for the 1N4742A. Substituting 1N4742A risks thermal runaway and premature failure. The 1N5349B also provides superior surge immunity (395 A vs none specified) and lower long-term drift.

What is the maximum allowable junction temperature for continuous operation of 1N5349B?

The 1N5349B supports continuous operation up to +150°C junction temperature under DC conditions. Pulsed operation may reach +200°C provided duty cycle remains low and peak duration is limited - as defined in Note 1 of the onsemi datasheet.

Does 1N5349B meet RoHS and lead-free soldering requirements?

Yes - the 1N5349B is manufactured in a Pb-free package compliant with RoHS Directive 2011/65/EU. It supports lead-free wave soldering at 260°C for 10 seconds at 1/16 inch from case, per onsemi's Soldering and Mounting Techniques Reference Manual.

How does the temperature coefficient affect 1N5349B's regulation accuracy over –40°C to +85°C ambient?

The 1N5349B exhibits a typical temperature coefficient of +5.5 mV/°C in the 11–75 V range. Over –40°C to +85°C ambient, assuming proper heatsinking, total V_Z shift is approximately ±0.7 V - calculable using TJ = TL + θ_JL × P_D and the published TC curve in Figure 3.

1N5349B Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: T-18, Axial

Packaging:: Bulk

Product Status:: Obsolete

Voltage - Zener (Nom) (Vz):: 12 V

Tolerance:: ±5%

Power - Max:: 5 W

Impedance (Max) (Zzt):: 2.5 Ohms

Current - Reverse Leakage @ Vr:: 2 µA @ 9.1 V

Voltage - Forward (Vf) (Max) @ If:: 1.2 V @ 1 A

Operating Temperature:: -65°C ~ 200°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: Axial

1N5349B FAQ

1.How can I place an order for 1N5349B through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N5349B 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 1N5349B reliable?

The price and inventory of 1N5349B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5349B is usually 5 days.

3.What payment methods are accepted for 1N5349B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5349B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N5349B?

1N5349B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N5349B 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 1N5349B?

For technical support, including 1N5349B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5349B requirements.

6.How does Aetrix verify that 1N5349B is sourced from the original manufacturer or authorized distributors?

All 1N5349B 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 1N5349B meets industry standards.

7.What is the process for return or replacement of 1N5349B?

All 1N5349B units undergo pre-shipment inspection (PSI). If there is an issue with 1N5349B, 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 1N5349B part is unused and in its original packaging.

Return procedure for 1N5349B:

1.Submit a request within 90 days.

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

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