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onsemi 1N4749A-T50R
- Part No.:
- 1N4749A-T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4749A-T50R.pdf
- Description:
- DIODE ZENER 24V 1W DO41
- Quantity:
- Payment:
- Shipping:
Inventory:9,051
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Product details
Overview
1N4749A-T50R from ON Semiconductor is a 24 V, 1 W axial-leaded Zener diode in DO-41 glass package, rated for ±5% tolerance, 10.5 Ω dynamic impedance at 11.4 mA test current, and 5 μA leakage at 19.2 V reverse voltage. It regulates voltage in low-power reference and protection circuits, including power supply feedback loops and overvoltage clamp stages.
For engineers reviewing the 1N4749A-T50R datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage accuracy, thermal derating (6.67 mW/°C above 50°C), junction temperature range (–65°C to +200°C), and non-repetitive peak reverse surge capability (190 mA).
Technical Context
The 1N4749A-T50R operates as a silicon planar Zener diode with sharp reverse breakdown at nominal 24 V, designed for stable DC voltage regulation under fixed-current bias. Its 1 W power dissipation is specified at lead temperature ≤50°C with 3/8″ lead length, and it exhibits 10.5 Ω Zener impedance (ZZ) at IZ = 11.4 mA.
It features a maximum leakage current of 5 μA at VR = 19.2 V, a knee impedance (ZZK) of 25 Ω at IZK = 0.25 mA, and withstands non-repetitive peak reverse currents up to 190 mA (8.3 ms square wave). The device is optimized for general-purpose voltage reference and transient suppression where precision and reliability outweigh ultra-low noise or fast response requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 22 V min / 24 V typ / 25.2 V max - defines regulated output voltage under 11.4 mA test current with ±5% tolerance. |
| Power Dissipation (PD) | 1.0 W @ TL ≤ 50°C - sets maximum continuous power handling before thermal derating begins. |
| Zener Impedance (ZZ) | 10.5 Ω @ IZ = 11.4 mA - indicates voltage regulation stiffness; lower values yield tighter regulation under load variation. |
| Leakage Current (IR) | 5 μA @ VR = 19.2 V - quantifies off-state conduction; critical for low-power standby circuits. |
| Operating Temperature | –65°C to +200°C - supports deployment in automotive engine compartments, industrial controls, and high-reliability environments. |
| Non-Repetitive Peak Reverse Current | 190 mA (8.3 ms) - defines surge immunity for transient overvoltage clamping without failure. |
Pinout & Package
1N4749A-T50R uses a DO-41 glass axial package with cathode indicated by a single color band. It has two terminals: anode and cathode. No PCB footprint or thermal pad; leads are tinned copper-clad steel, intended for through-hole mounting with 3/8″ lead length standard for power rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side in reverse-bias regulation; carries full load current during Zener operation. |
| Cathode | Zener breakdown terminal | Marked with color band; connected to higher-potential side; defines regulated voltage reference point relative to anode. |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables predictable regulation without post-manufacturing trimming in cost-sensitive applications. |
| 1 W power rating with defined thermal derating | Supports stable operation up to 50°C ambient without heatsinking; linear derating ensures safe margin beyond that point. |
| Low leakage (5 μA @ 19.2 V) | Minimizes quiescent current loss in battery-powered or energy-harvesting reference circuits. |
| DO-41 glass package with axial leads | Provides mechanical robustness, hermetic seal against moisture, and compatibility with legacy through-hole assembly processes. |
Applications
| Power Supply Feedback Reference | Overvoltage Clamp Protection |
|---|---|
Use Scenario: Used in the optocoupler feedback path of isolated AC/DC flyback converters to maintain ±5% output voltage regulation. IC Role / Device Role / Timing Role: Voltage reference element providing stable 24 V threshold for TL431 or similar shunt regulator control. Use Value: Maintains regulation accuracy across line/load variations and temperature drift due to tight VZ tolerance and low ZZ. |
Use Scenario: Placed across sensitive IC inputs (e.g., microcontroller reset pins) to limit transient spikes from ESD or inductive switching. IC Role / Device Role / Timing Role: Passive clamping device diverting excess energy to ground when voltage exceeds 25.2 V. Use Value: Absorbs 190 mA non-repetitive surges without degradation, protecting downstream logic from latch-up or damage. |
| Industrial Sensor Signal Conditioning | Automotive Body Control Module Reference |
Use Scenario: Provides stable bias voltage for analog front-end op-amps measuring 4–20 mA loop current in PLC I/O modules. IC Role / Device Role / Timing Role: Precision DC reference source ensuring consistent gain and offset calibration across temperature. Use Value: –65°C to +200°C operating range and low thermal coefficient enable reliable performance in unheated enclosures. |
Use Scenario: Supplies regulated 24 V reference to window lift motor controllers and door lock actuators in 24 V vehicle systems. IC Role / Device Role / Timing Role: Standalone voltage stabilizer compensating for battery voltage fluctuations (18–32 V). Use Value: Withstands under-hood temperatures and load dump transients while maintaining regulation within ±5%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4749A (no suffix) | Identical electrical specs; same DO-41 package; differs only in packaging format (T50R = tape-and-reel, standard = bulk/ammopack). | No functional difference; suitable for identical use cases including automated SMT placement (T50R) vs. manual/hand-soldered prototyping (bulk). | Select 1N4749A-T50R for pick-and-place assembly; choose 1N4749A for low-volume evaluation or repair. |
| BZX55C24 | Same 24 V nominal Zener voltage and ±5% tolerance, but rated at 500 mW (not 1 W); DO-35 package (smaller, lower thermal mass). | Not suitable for 1 W continuous dissipation; limited to lower-power references or signal-level clamping where thermal budget is constrained. | Use BZX55C24 only if power demand stays below 400 mW and board space is critical; otherwise, 1N4749A-T50R provides superior thermal margin. |
Compared with 1N4749A-T50R, the unsuffixed 1N4749A offers identical performance in different packaging, while BZX55C24 trades power capability for smaller size-making the former ideal for production automation and the latter viable only in thermally restricted, sub-500 mW designs.
Availability
1N4749A-T50R is available at Aetrix Electronics and suitable for power supply feedback references, overvoltage clamp protection, and industrial sensor signal conditioning requiring stable component supply and long-term manufacturability.
Supply support for 1N4749A-T50R 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 developed as a standardized family of general-purpose Zener diodes targeting cost-effective, high-reliability voltage regulation in power conversion, protection, and reference circuits across broad industrial and consumer applications.
FAQ
What is the Zener voltage tolerance of the 1N4749A-T50R?
The 1N4749A-T50R has a Zener voltage tolerance of ±5%, with a nominal value of 24 V, minimum of 22 V, and maximum of 25.2 V at 11.4 mA test current. This tolerance is guaranteed per ON Semiconductor's 1N4728A–1N4758A datasheet Rev. 8, and applies across the full operating temperature range. The 1N4749A-T50R maintains this specification without binning or sorting.
Can the 1N4749A-T50R be used in surface-mount designs?
No-the 1N4749A-T50R is packaged in the DO-41 axial leaded glass case and is not a surface-mount device. It requires through-hole mounting with 3/8″ lead length for rated 1 W power dissipation. For SMT alternatives, consider the MMBZ5249BS (SOT-23, 24 V, 225 mW) or BZX84-C24 (SOT-23, 24 V, 300 mW), but note their lower power ratings and different thermal behavior versus the 1N4749A-T50R.
What is the maximum allowable junction temperature for the 1N4749A-T50R?
The 1N4749A-T50R has a maximum junction temperature (TJ) of +200°C and a storage temperature range of –65°C to +200°C. Thermal design must ensure that actual junction temperature remains within this limit under worst-case power dissipation and ambient conditions. Derating begins at 50°C lead temperature, reducing power by 6.67 mW/°C above that point.
How does the 1N4749A-T50R compare to the 1N4748A in terms of Zener voltage?
The 1N4749A-T50R has a nominal Zener voltage of 24 V (22–25.2 V), whereas the 1N4748A is rated at 22 V (20.9–23.1 V). Both share identical package (DO-41), power rating (1 W), tolerance (±5%), and thermal specifications. The 1N4749A-T50R is not a drop-in replacement for the 1N4748A unless the circuit is specifically designed for 24 V regulation-voltage mismatch may cause over-regulation or instability.
Is the 1N4749A-T50R RoHS compliant and halogen-free?
Yes-the 1N4749A-T50R meets RoHS Directive 2011/65/EU and is halogen-free per ON Semiconductor's product compliance documentation. The DO-41 glass package contains no lead in solderable terminations (lead-free tinning), and all materials comply with JEDEC J-STD-609A Class 1 for marking and IPC-1752 for substance declaration. Full compliance data is available in ON Semiconductor's PPAP documentation for the 1N47xxA family.
1N4749A-T50R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-T50R FAQ
1.How can I place an order for 1N4749A-T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4749A-T50R 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-T50R reliable?
The price and inventory of 1N4749A-T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4749A-T50R is usually 5 days.
3.What payment methods are accepted for 1N4749A-T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4749A-T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4749A-T50R?
1N4749A-T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4749A-T50R 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-T50R?
For technical support, including 1N4749A-T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4749A-T50R requirements.
6.How does Aetrix verify that 1N4749A-T50R is sourced from the original manufacturer or authorized distributors?
All 1N4749A-T50R 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-T50R meets industry standards.
7.What is the process for return or replacement of 1N4749A-T50R?
All 1N4749A-T50R units undergo pre-shipment inspection (PSI). If there is an issue with 1N4749A-T50R, 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-T50R part is unused and in its original packaging.
Return procedure for 1N4749A-T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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