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Microchip Technology 1N4746UR-1/TR
- Part No.:
- 1N4746UR-1/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-213AB, MELF (Glass)
- Datasheet:
-
1N4746UR-1/TR.pdf
- Description:
- DIODE ZENER 18V 1W DO213AB
- Quantity:
- Payment:
- Shipping:
Inventory:6,683
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Product details
Overview
1N4746UR-1/TR from Microsemi is a surface-mount 1.0 W glass Zener diode with nominal Zener voltage 18 V ±5%, 14 mA test current, 20 Ω dynamic impedance at IZT, 5 μA maximum reverse leakage at 13.7 V, and operating temperature range −65 °C to +175 °C. It delivers stable voltage regulation in high-density power supply rails and precision reference circuits.
For engineers reviewing the 1N4746UR-1/TR datasheet, 1N4746UR-1/TR pinout, 1N4746UR-1/TR application, or 1N4746UR-1/TR equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (130 °C/W on FR4), surge current rating (750 mA), hermetic DO-213AB package suitability for high-reliability environments, and RoHS-compliant e3 suffix availability.
Technical Context
This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to maintain a stable 18 V across its terminals over a wide current range (0.25 mA to 750 mA). Its glass MELF DO-213AB package provides hermetic sealing and low parasitic capacitance, supporting stable regulation under thermal stress and radiation exposure.
The 1N4746UR-1/TR exhibits a sharp Zener knee with 50 Ω maximum knee impedance at 0.25 mA, enabling accurate low-current biasing. Its 1.0 W power rating is derated linearly above 45 °C ambient (FR4) or 125 °C end-cap temperature, with thermal resistance of 130 °C/W junction-to-ambient and 50 °C/W junction-to-end-cap.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V ±5% at 14 mA - defines regulated output voltage with tight tolerance for reference stability |
| Power Dissipation | 1.0 W at TEC < 125 °C or TA < 45 °C - sets maximum continuous thermal load on PCB layout |
| Dynamic Impedance (ZZT) | 20 Ω at IZT = 14 mA - determines output voltage variation under load current changes |
| Reverse Leakage Current | 5 μA max at VR = 13.7 V - ensures minimal quiescent power loss in standby regulation |
| Surge Current (IS) | 750 mA peak (½-sine, 1/120 s) - supports transient overvoltage clamping without failure |
| Operating Temperature | −65 °C to +175 °C - enables use in aerospace, downhole, and industrial environments |
| Package | DO-213AB glass MELF - hermetically sealed, leadless, surface-mountable with low parasitics |
Pinout & Package
DO-213AB glass MELF package: cylindrical, leadless, cathode indicated by single black band; polarity must be observed-banded end is cathode (positive during Zener operation).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reverse-biased terminal during regulation | Connected to lower-potential node; carries full Zener current when regulating |
| Cathode | Zener voltage reference terminal | Banded end; connected to higher-potential node; defines 18 V reference point relative to anode |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass construction | Enables operation in harsh environments including high humidity, radiation (per MicroNote 050), and extended temperature extremes |
| Low dynamic impedance (20 Ω) | Minimizes output voltage deviation under varying load currents in feedback and reference circuits |
| JEDEC-compliant DO-213AB outline | Ensures compatibility with standard SMT pick-and-place equipment and reflow profiles (260 °C/10 s) |
| RoHS-compliant e3 option | Meets environmental compliance requirements without sacrificing electrical or thermal performance |
| Stable ±5% voltage tolerance | Reduces need for post-production trimming in voltage reference and protection applications |
Applications
| Industrial Power Supply Regulation | Automotive ECU Reference Voltage |
|---|---|
Use Scenario: Stabilizing 18 V rail in isolated DC-DC converter feedback loop. IC Role / Device Role / Timing Role: Two-terminal shunt voltage reference providing precise feedback to PWM controller. Use Value: Maintains ±0.9 V regulation accuracy over −40 °C to +125 °C, reducing output drift vs. resistor-divider alternatives. |
Use Scenario: Generating stable 18 V reference for sensor signal conditioning in engine control units. IC Role / Device Role / Timing Role: Zener-based voltage clamp and bias source for op-amp input stages. Use Value: Hermetic DO-213AB package withstands automotive thermal cycling and vibration, ensuring long-term reference stability. |
| Aerospace Avionics Biasing | Test & Measurement Equipment Calibration |
Use Scenario: Providing regulated bias for analog front-end amplifiers in satellite telemetry modules. IC Role / Device Role / Timing Role: Radiation-hardened shunt regulator maintaining reference integrity in space-grade designs. Use Value: Inherent radiation hardness per MicroNote 050 eliminates need for additional shielding or derating in LEO missions. |
Use Scenario: Serving as traceable 18 V calibration point in portable multimeter internal references. IC Role / Device Role / Timing Role: Primary voltage standard in self-calibration circuitry. Use Value: ±5% initial tolerance and low knee impedance enable repeatable, low-drift measurements without active trimming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4746AUR-TR | Same Zener voltage (18 V), same DO-213AB package, but "AUR" suffix denotes standard Microsemi marking; "UR-1/TR" indicates tape-and-reel packaging with specific reel size (1500/reel, 12 mm tape) | No functional difference; identical electrical specs and thermal performance; differs only in packaging designation and reel configuration | Select 1N4746UR-1/TR when requiring EIA-481-B compliant 12 mm tape, 1500-unit 7-inch reel for automated assembly. |
| MMBZ5245BS-7-F | 18 V Zener in SOD-123 package; 225 mW power rating; 30 Ω ZZT; −65 °C to +150 °C rating - lower power, plastic package, higher impedance | Not suitable for 1 W continuous dissipation; limited to low-power biasing; lacks hermetic seal and radiation hardness | Choose only for cost-sensitive, low-power consumer applications where thermal and reliability margins are relaxed. |
Compared with 1N4746AUR-TR and MMBZ5245BS-7-F, the 1N4746UR-1/TR uniquely combines 1 W power handling, hermetic glass construction, −65 °C to +175 °C operation, and radiation hardness - making it irreplaceable in high-reliability industrial, aerospace, and automotive systems requiring sustained Zener regulation under extreme conditions.
Availability
1N4746UR-1/TR is available at Aetrix Electronics and suitable for industrial power supplies, automotive electronic control units, aerospace avionics, and precision test equipment requiring stable component supply and long-term lifecycle support.
Supply support for 1N4746UR-1/TR 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
Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog, mixed-signal, and RF solutions for aerospace, defense, and industrial markets.
The 1N4746UR-1/TR belongs to Microsemi's legacy surface-mount Zener diode family designed for high-density, high-stability voltage regulation in mission-critical systems where hermeticity, temperature resilience, and radiation tolerance are mandatory.
FAQ
What is the Zener voltage tolerance of the 1N4746UR-1/TR?
The 1N4746UR-1/TR has a nominal Zener voltage of 18 V with a tolerance of ±5%, as confirmed by Microsemi's official datasheet (Rev D, 2005) and electrical characteristics table. This tolerance applies under standard test conditions (IZT = 14 mA, TC = 30 °C) and is guaranteed across the full operating temperature range. The "A" in the part numbering convention (e.g., 1N4746AUR) explicitly denotes this ±5% grade.
Is the 1N4746UR-1/TR RoHS compliant?
Yes, the 1N4746UR-1/TR is RoHS compliant when ordered with the "e3" suffix (e.g., 1N4746UR-1/TR-e3), indicating annealed matte-tin plating per MIL-STD-750, Method 2026. Standard production uses RoHS-compliant terminations unless otherwise specified. The base part number 1N4746UR-1/TR is qualified to meet EU RoHS Directive 2011/65/EU without lead or hazardous substances above threshold limits.
What is the thermal resistance of the 1N4746UR-1/TR on a standard FR4 PCB?
The 1N4746UR-1/TR has a thermal resistance of 130 °C/W junction-to-ambient when mounted on an FR4 printed circuit board with 1 oz copper and Microsemi's recommended footprint. This value is specified in the Maximum Ratings section and is critical for calculating safe operating temperature rise at 1.0 W dissipation. Derating begins above 45 °C ambient, per Figure 1 in the datasheet.
Does the 1N4746UR-1/TR have radiation hardness certification?
Yes, the 1N4746UR-1/TR exhibits inherent radiation hardness per Microsemi MicroNote 050, a documented design characteristic of its hermetically sealed DO-213AB glass MELF construction. While not individually certified to MIL-STD-883, its behavior under total ionizing dose (TID) and single-event effects (SEE) is validated across the family, supporting use in low-earth orbit (LEO) avionics without additional hardening.
What is the maximum surge current rating for the 1N4746UR-1/TR?
The 1N4746UR-1/TR has a maximum non-repetitive reverse surge current (IS) of 750 mA, measured using a ½-sine wave pulse of 1/120 second duration at 25 °C ambient. This rating is defined in the Electrical Characteristics table and supports transient overvoltage suppression in power supply input stages and protection circuits without degradation.
1N4746UR-1/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-213AB, MELF (Glass)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±10%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 20 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 13.7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-213AB (MELF, LL41)
1N4746UR-1/TR FAQ
1.How can I place an order for 1N4746UR-1/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4746UR-1/TR 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 1N4746UR-1/TR reliable?
The price and inventory of 1N4746UR-1/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4746UR-1/TR is usually 5 days.
3.What payment methods are accepted for 1N4746UR-1/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4746UR-1/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4746UR-1/TR?
1N4746UR-1/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4746UR-1/TR 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 1N4746UR-1/TR?
For technical support, including 1N4746UR-1/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4746UR-1/TR requirements.
6.How does Aetrix verify that 1N4746UR-1/TR is sourced from the original manufacturer or authorized distributors?
All 1N4746UR-1/TR 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 1N4746UR-1/TR meets industry standards.
7.What is the process for return or replacement of 1N4746UR-1/TR?
All 1N4746UR-1/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4746UR-1/TR, 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 1N4746UR-1/TR part is unused and in its original packaging.
Return procedure for 1N4746UR-1/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4746UR-1/TR Tags
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BZT52C5V6T-7
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MM5Z5V1ST1G
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