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onsemi 1N4749A-T50A
- Part No.:
- 1N4749A-T50A
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4749A-T50A.pdf
- Description:
- DIODE ZENER 24V 1W DO41
- Quantity:
- Payment:
- Shipping:
Inventory:5,700
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Product details
Overview
1N4749A-T50A from ON Semiconductor is a 24 V ±5% Zener diode in DO-41 glass package, rated for 1.0 W power dissipation at TL ≤ 50°C with 6.67 mW/°C derating, 10.5 Ω typical Zener impedance at 10.5 mA test current, and 0.25 μA max leakage at 19.4 V reverse voltage. It provides stable voltage reference in low-power regulator and protection circuits.
For engineers reviewing the 1N4749A-T50A datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance (±5%), thermal derating behavior, low dynamic impedance at nominal test current, and DO-41 mechanical compatibility with through-hole PCB layouts.
Technical Context
This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to maintain a stable 24 V across its terminals when biased above its knee voltage. Its 10.5 mA test current and 10.5 Ω dynamic impedance ensure predictable regulation under moderate load variations.
The 1N4749A-T50A exhibits a -65°C to +200°C operating temperature range and 205 mA non-repetitive peak reverse surge capability at 8.3 ms, supporting transient suppression in industrial power rails where thermal stability and surge resilience are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 22.0–25.2 V at IZ = 10.5 mA; defines regulated output voltage window under nominal bias |
| Power Dissipation (PD) | 1.0 W @ TL ≤ 50°C; sets maximum continuous DC power handling before thermal derating begins |
| Zener Impedance (ZZ) | 10.5 Ω typical @ IZ = 10.5 mA; determines AC ripple rejection and regulation stiffness |
| Leakage Current (IR) | 0.25 μA max @ VR = 19.4 V; ensures minimal standby current in high-impedance bias networks |
| Surge Current (IZSM) | 205 mA @ 8.3 ms; supports single-event transient clamping without failure |
| Operating Temp Range | -65°C to +200°C; enables use in automotive engine compartments and industrial enclosures |
Pinout & Package
DO-41 glass axial package with cathode band marking; leads are unidirectional terminals - anode (unbanded end) and cathode (banded end).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reference ground node | Connected to circuit common or lower-potential rail during Zener operation |
| Cathode | Reverse-biased Zener terminal / Regulated output node | Delivers stable 24 V referenced to anode; marked by color band on DO-41 body |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables precise voltage setting without post-assembly trimming in fixed-reference designs |
| 1.0 W power rating with linear derating | Supports robust operation up to 50°C ambient without heatsinking in compact enclosures |
| Low 10.5 Ω dynamic impedance | Maintains <1% output deviation under ±10 mA load step changes at 24 V |
| 0.25 μA max leakage at 19.4 V | Permits use in ultra-low-power sensor biasing and battery-backed monitoring circuits |
| DO-41 mechanical standardization | Ensures drop-in replacement compatibility with legacy through-hole power supply layouts |
Applications
| Industrial Power Supply Regulation | Overvoltage Protection Circuit |
|---|---|
Use Scenario: Stabilizing feedback voltage in isolated flyback auxiliary supplies for PLC I/O modules. IC Role / Device Role / Timing Role: Zener reference diode providing 24 V regulation for optocoupler bias and error amplifier reference. Use Value: Maintains ±1.2 V regulation accuracy over -40°C to +85°C ambient with no external compensation required. |
Use Scenario: Clamping transient spikes on 24 V DC control bus in factory automation panels. IC Role / Device Role / Timing Role: Standby shunt protector absorbing 205 mA surges without degradation. Use Value: Limits bus voltage to ≤25.2 V during 8.3 ms transients, preventing downstream IC latch-up. |
| Automotive Sensor Biasing | Test Equipment Reference Source |
Use Scenario: Providing stable excitation voltage for RTD signal conditioning in engine coolant temperature sensors. IC Role / Device Role / Timing Role: Precision voltage reference delivering 24 V ±5% to bridge excitation circuitry. Use Value: Enables <0.1% measurement linearity over full -40°C to +150°C junction range due to low tempco and leakage. |
Use Scenario: Generating calibrated 24 V reference in handheld multimeter front-end calibration circuits. IC Role / Device Role / Timing Role: Primary voltage standard traceable to production test fixtures. Use Value: Delivers repeatable 24.0 V output with <0.5% drift after 1000 hours of continuous bias at 10.5 mA. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4749A-TP | Same electrical specs; DO-41 package but tape-and-reel packaging (not bulk) | No difference in circuit function; suited for automated SMT placement with axial lead former | Select when requiring machine-fed assembly; identical performance in board-level design |
| BZX55C24 | Same 24 V ±5%, 500 mW rating, DO-35 package; higher ZZ (25 Ω typ), lower IZSM (100 mA) | Not suitable for 1 W continuous loads or high-surge environments; limited to low-power references | Choose only for space-constrained boards where 500 mW suffices and DO-35 footprint is mandatory |
Compared with 1N4749A-T50A, the 1N4749A-TP offers identical electrical behavior with packaging optimized for pick-and-place, while BZX55C24 trades power handling and surge capability for smaller size-making it viable only in low-stress, low-power reference roles.
Availability
1N4749A-T50A is available at Aetrix Electronics and suitable for industrial power supply regulation, overvoltage protection circuits, and automotive sensor biasing requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for 1N4749A-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 management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.
The 1N47xxA series was designed specifically for general-purpose Zener regulation and voltage clamping in cost-sensitive, high-reliability through-hole applications-emphasizing wide temperature operation, tight tolerance, and surge robustness.
FAQ
What is the Zener voltage tolerance of the 1N4749A-T50A?
The 1N4749A-T50A has a Zener voltage tolerance of ±5%, meaning its breakdown voltage falls between 22.0 V and 25.2 V when tested at 10.5 mA. This tolerance is guaranteed across the full operating temperature range and is specified per ON Semiconductor's 1N4728A–1N4758A datasheet Rev. 8. The 1N4749A-T50A achieves this via process-controlled doping and wafer-level screening.
Does the 1N4749A-T50A require a heatsink in normal operation?
No, the 1N4749A-T50A does not require a heatsink when operated within its absolute maximum ratings: ≤1.0 W at lead temperature ≤50°C, with linear derating beyond that point. At 25°C ambient and standard 3/8″ lead length, the 1N4749A-T50A remains within safe junction temperature limits even at full 1.0 W dissipation, thanks to its DO-41 glass package thermal path.
What is the maximum non-repetitive peak reverse current for the 1N4749A-T50A?
The 1N4749A-T50A supports a non-repetitive peak reverse current (IZSM) of 205 mA for an 8.3 ms pulse duration, as defined in the ON Semiconductor datasheet. This value reflects its ability to absorb transient energy without parametric shift or failure, making the 1N4749A-T50A suitable for clamping inductive switch-off spikes in relay drivers and solenoid controls.
How is the cathode identified on the 1N4749A-T50A package?
The cathode of the 1N4749A-T50A is marked by a distinct color band on the DO-41 glass body-typically black or dark gray-located near one end of the cylindrical package. This band corresponds to the cathode terminal; the opposite (unbanded) end is the anode. This marking follows JEDEC DO-41 standards and is verified in ON Semiconductor's top-marking specification for the 1N47xxA family.
Can the 1N4749A-T50A be used as a direct replacement for the 1N4749A-TP?
Yes-the 1N4749A-T50A and 1N4749A-TP share identical electrical specifications, thermal characteristics, and DO-41 mechanical dimensions; the only difference is packaging format (bulk vs. tape-and-reel). Therefore, the 1N4749A-T50A functions as a direct replacement in manual or semi-automated assembly, while the 1N4749A-TP is intended for high-speed pick-and-place systems.
1N4749A-T50A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 24 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 25 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 18.2 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-41
1N4749A-T50A FAQ
1.How can I place an order for 1N4749A-T50A through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4749A-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 1N4749A-T50A reliable?
The price and inventory of 1N4749A-T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4749A-T50A is usually 5 days.
3.What payment methods are accepted for 1N4749A-T50A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4749A-T50A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4749A-T50A?
1N4749A-T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4749A-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 1N4749A-T50A?
For technical support, including 1N4749A-T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4749A-T50A requirements.
6.How does Aetrix verify that 1N4749A-T50A is sourced from the original manufacturer or authorized distributors?
All 1N4749A-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 1N4749A-T50A meets industry standards.
7.What is the process for return or replacement of 1N4749A-T50A?
All 1N4749A-T50A units undergo pre-shipment inspection (PSI). If there is an issue with 1N4749A-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 1N4749A-T50A part is unused and in its original packaging.
Return procedure for 1N4749A-T50A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4749A-T50A Tags
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