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Diodes Incorporated 1N4749A-T
- Part No.:
- 1N4749A-T
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4749A-T.pdf
- Description:
- DIODE ZENER 24V 1W DO41
- Quantity:
- Payment:
- Shipping:
Inventory:7,389
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Product details
Overview
1N4749A-T from Diodes Incorporated is a 1.0 W, 24 V ±5% glass-passivated Zener diode in DO-41 package, with 25 Ω zener impedance at 10.5 mA test current, 18.2 V minimum knee voltage, and -65°C to +175°C operating temperature range; used for precision voltage regulation and overvoltage protection in power supply feedback loops.
For engineers reviewing the 1N4749A-T datasheet, 1N4749A-T pinout, 1N4749A-T application, or 1N4749A-T equivalent, key selection criteria include nominal zener voltage (24 V), power rating (1.0 W), zener impedance (25 Ω), temperature coefficient (+0.06 to +0.095 %/°C), and DO-41 mechanical compatibility with through-hole PCB assembly.
Technical Context
This Zener diode operates in reverse breakdown mode to maintain stable reference voltage under varying load and temperature conditions. Its 24 V nominal zener voltage is specified at 10.5 mA test current (IZT), with sharp knee characteristics confirmed by dual-point impedance measurement per JEDEC standards.
The device exhibits a positive temperature coefficient (+0.06 to +0.095 %/°C), enabling predictable voltage drift across industrial temperature ranges. Thermal resistance junction-to-ambient is 175 °C/W at 50°C ambient, derating linearly at 6.67 mW/°C above that point.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 24 V ±5% - defines regulated output voltage in shunt regulator circuits |
| Power Dissipation | 1.0 W - maximum continuous DC power handling at 25°C ambient |
| Zener Impedance | 25 Ω at IZT = 10.5 mA - determines regulation accuracy under dynamic load changes |
| Test Current | 10.5 mA - standardized bias point for voltage and impedance specification |
| Maximum Reverse Leakage | 5.0 µA at VR = 18.2 V - ensures low standby current in high-impedance reference paths |
| Temperature Coefficient | +0.06 to +0.095 %/°C - quantifies voltage drift magnitude and direction with temperature |
| Operating Temperature | -65°C to +175°C - supports deployment in automotive under-hood and industrial control environments |
Pinout & Package
DO-41 glass axial package with cathode band marking; leads are Sn96.5Ag3.5 solderable per MIL-STD-202, Method 208; polarity defined by cathode band; weight ≈ 0.35 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference node | Connected to lower-potential side of regulated circuit; forms reference ground return path |
| Cathode | Zener breakdown terminal / voltage regulation node | Connected to higher-potential side; clamps voltage to 24 V when reverse-biased above knee |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivation | Enables stable long-term zener voltage performance and moisture resistance in harsh environments |
| UL 94V-0 flammability rating | Meets safety requirements for enclosed power supplies and industrial equipment enclosures |
| RoHS-compliant finish | Sn96.5Ag3.5 termination supports lead-free reflow and wave soldering processes |
| Sharp knee characteristic | Validated via dual-point impedance testing to reject units with unstable breakdown behavior |
| Thermal derating profile | Linear 6.67 mW/°C reduction above 50°C enables accurate thermal design margining |
Applications
| Switch-Mode Power Supply Feedback | Industrial Sensor Reference |
|---|---|
Use Scenario: Provides stable 24 V reference for optocoupler-based feedback in 48 V input DC-DC converters. IC Role / Device Role / Timing Role: Shunt voltage regulator establishing precise error amplifier reference point. Use Value: Maintains ±1% output regulation across line/load transients due to low 25 Ω zener impedance. |
Use Scenario: Supplies excitation voltage to 4–20 mA current-loop pressure sensors in factory automation systems. IC Role / Device Role / Timing Role: Precision voltage source replacing active references where cost and simplicity are critical. Use Value: Delivers stable 24 V with <5 µA leakage, minimizing sensor offset error in high-impedance signal chains. |
| Overvoltage Clamp Protection | Microcontroller Reset Circuit |
Use Scenario: Clamps 24 V rail surges during inductive load switching in PLC I/O modules. IC Role / Device Role / Timing Role: Transient voltage suppressor limiting rail excursion to safe levels. Use Value: Absorbs 8.3 ms surge energy up to 190 A peak without degradation, per datasheet surge rating. |
Use Scenario: Generates clean reset threshold for 3.3 V microcontrollers powered from 24 V intermediate rail. IC Role / Device Role / Timing Role: Zener-based voltage divider defining brown-out detection level. Use Value: Ensures reliable reset assertion down to -65°C using verified low-temperature leakage performance. |
Availability
1N4749A-T is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial sensor interfaces, overvoltage clamp circuits, and microcontroller reset networks requiring stable component supply and full traceability.
Supply support for 1N4749A-T 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, serving automotive, industrial, computing, and consumer markets with high-reliability components.
The 1N47xxA series belongs to Diodes' legacy Zener diode product line, designed specifically for cost-sensitive, high-volume voltage regulation and protection applications in industrial power systems.
FAQ
What is the maximum surge current rating for 1N4749A-T?
The 1N4749A-T is rated for 190 A peak surge current under an 8.3 ms single half-sine wave condition, as specified in the Electrical Characteristics table. This value reflects its capability to absorb transient energy without parametric shift or failure, validated per industry-standard surge test protocols.
Is 1N4749A-T RoHS compliant?
Yes - the 1N4749A-T features a Sn96.5Ag3.5 lead finish and complies with EU Directive 2002/95/EC (RoHS), including applicable exemptions for glass and high-temperature solder as noted in the datasheet's footnote 2.
How does the temperature coefficient affect regulation accuracy?
With a +0.06 to +0.095 %/°C temperature coefficient, the 1N4749A-T's zener voltage increases by approximately 14.4–22.8 mV per °C rise from 25°C. This must be factored into system-level tolerance budgets for applications operating across wide temperature ranges.
Can 1N4749A-T replace 1N4749A-A in the same footprint?
Yes - both variants share identical DO-41 glass package dimensions, electrical specifications, and thermal characteristics; only packaging differs (tape-and-reel vs. ammo pack). Mechanical fit, soldering profile, and circuit performance are fully interchangeable.
1N4749A-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- 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:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-41
1N4749A-T FAQ
1.How can I place an order for 1N4749A-T through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4749A-T 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-T reliable?
The price and inventory of 1N4749A-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4749A-T is usually 5 days.
3.What payment methods are accepted for 1N4749A-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4749A-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4749A-T?
1N4749A-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4749A-T 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-T?
For technical support, including 1N4749A-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4749A-T requirements.
6.How does Aetrix verify that 1N4749A-T is sourced from the original manufacturer or authorized distributors?
All 1N4749A-T 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-T meets industry standards.
7.What is the process for return or replacement of 1N4749A-T?
All 1N4749A-T units undergo pre-shipment inspection (PSI). If there is an issue with 1N4749A-T, 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-T part is unused and in its original packaging.
Return procedure for 1N4749A-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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