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Microchip Technology 1N749D-1E3
- Part No.:
- 1N749D-1E3
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N749D-1E3.pdf
- Description:
- DIODE ZENER 4.3V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:7,674
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Product details
Overview
1N749D-1E3 from Microsemi is a 500 mW, 4.3 V ±1% tolerance silicon Zener diode in DO-35 (DO-204AH) glass axial-leaded package, qualified to JANTXV level per MIL-PRF-19500/127, with dynamic impedance of 18 Ω at 20 mA and temperature coefficient of –0.055%/°C / +0.020%/°C, used for precision voltage regulation in military power supplies and reference circuits.
For engineers reviewing the 1N749D-1E3 datasheet, 1N749D-1E3 pinout, 1N749D-1E3 application, or 1N749D-1E3 equivalent, key selection criteria include ±1% Zener voltage tolerance, JANTXV qualification, DO-35 thermal resistance (250 °C/W junction-to-lead), reverse leakage ≤2 µA at 1.0 V, and radiation-hardened construction per MicroNote 050.
Technical Context
The 1N749D-1E3 operates as a two-terminal voltage reference device, conducting in reverse breakdown at precisely 4.3 V ±1% when biased above its knee current (IZK), with low dynamic impedance (18 Ω) ensuring stable regulation under varying load currents. Its metallurgically bonded junction provides enhanced reliability over standard diffused structures.
Designed for high-reliability environments, it supports operation from –65 °C to +175 °C, exhibits minimal capacitance, and meets MIL-STD-750 ESD immunity (Method 1020). The cathode band polarity marking and tin-lead or RoHS-compliant matte-tin plating ensure consistent assembly and solderability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 4.3 V ±1% at IZT = 20 mA - enables tight regulation in precision references and feedback loops |
| Power Dissipation | 500 mW at TL = 50 °C - supports robust operation in conduction-cooled military PCBs |
| Dynamic Impedance (ZZT) | 18 Ω at 20 mA - minimizes output voltage variation under dynamic load transients |
| Reverse Leakage (IR) | ≤2 µA at VR = 1.0 V - ensures low quiescent current in battery-backed or low-power systems |
| Temp. Coefficient (αVZ) | –0.055%/°C / +0.020%/°C - allows predictable drift compensation across –65 to +175 °C range |
| Junction-to-Lead Rθ | 250 °C/W - defines thermal path for lead-mounted derating per MIL-PRF-19500/127 |
| Package | DO-35 (DO-204AH) glass axial - hermetically sealed, radiation-hardened, and JEDEC-registered |
Pinout & Package
DO-35 (DO-204AH) glass axial-leaded package: hermetically sealed, cathode indicated by single black band; leads are tin-lead or RoHS-compliant matte-tin plated, solderable per MIL-STD-750 Method 2026; weight ≈ 0.2 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference node | Connected to lower-potential side in reverse-biased regulation; unmarked end of axial body |
| Cathode | Zener breakdown terminal / regulation output node | Banded end; connected to higher-potential side during Zener operation; defines regulated voltage reference point |
Key Features
| Feature | Design Value |
|---|---|
| JANTXV qualification | Fully qualified per MIL-PRF-19500/127 - guarantees performance and screening for aerospace and defense programs |
| ±1% Zener tolerance | Specified by 'D' suffix - reduces calibration overhead and improves system-level accuracy without trimming |
| Metallurgical bond | Internal metal-glass junction - enhances thermal cycling endurance and long-term parameter stability vs. diffused junctions |
| Radiation hardness | Inherently radiation-hard per Microsemi MicroNote 050 - suitable for space-qualified and nuclear instrumentation applications |
| RoHS compliance | e3 suffix indicates RoHS-compliant matte-tin plating - satisfies environmental requirements for commercial-grade variants |
Applications
| Military Power Supply Regulation | Precision Voltage Reference |
|---|---|
Use Scenario: Regulating auxiliary rails in airborne radar power modules operating from –55 °C to +125 °C ambient. IC Role / Device Role / Timing Role: Two-terminal shunt regulator providing stable 4.3 V reference for op-amp biasing and DAC reference buffers. Use Value: ±1% tolerance and JANTXV qualification ensure first-pass compliance with MIL-HDBK-217F failure rate models and DO-160E thermal shock requirements. | Use Scenario: Setting threshold voltage in radiation-tolerant satellite telemetry comparators. IC Role / Device Role / Timing Role: Zener-based reference node for window detectors monitoring solar array bus voltage. Use Value: Inherent radiation hardness and –65 °C to +175 °C operational range eliminate need for shielding or derating in LEO missions. |
| Industrial Sensor Excitation | Avionics Signal Conditioning |
Use Scenario: Biasing bridge sensors in oil & gas downhole pressure transducers exposed to 175 °C wellbore temperatures. IC Role / Device Role / Timing Role: Stable excitation source for Wheatstone bridge arms requiring low-drift, low-noise DC bias. Use Value: Low dynamic impedance (18 Ω) and predictable αVZ minimize sensor offset drift across full temperature range. | Use Scenario: Providing regulated supply to analog front-end circuitry in flight control actuator controllers. IC Role / Device Role / Timing Role: Shunt regulator for local 4.3 V rail powering op-amps and ADC drivers in redundant signal chains. Use Value: Hermetic DO-35 package and MIL-PRF-19500/127 screening ensure zero moisture ingress and validated burn-in reliability for DO-178C Level A software environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N749A-1 | ±5% tolerance (A suffix), same VZ nominal and package | Lacks tight tolerance needed for high-accuracy references; acceptable for general-purpose regulation | Select when ±5% regulation suffices and cost sensitivity outweighs precision requirements |
| 1N749C-1 | ±2% tolerance (C suffix), identical thermal and electrical specs otherwise | Balances tighter tolerance than A-grade with lower cost than D-grade; no radiation hardening documentation | Choose for industrial applications needing better accuracy than A-grade but without JANTXV screening |
Compared with 1N749A-1 and 1N749C-1, the 1N749D-1E3 delivers the tightest voltage tolerance (±1%) and full JANTXV qualification, making it uniquely suited for mission-critical aerospace references where calibration stability and radiation resilience are non-negotiable.
Availability
1N749D-1E3 is available at Aetrix Electronics and suitable for military power supply regulation, precision voltage reference design, and radiation-hardened sensor excitation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 1N749D-1E3 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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability, radiation-hardened, and aerospace-grade analog and mixed-signal components.
The 1N749D-1E3 belongs to Microsemi's legacy MIL-PRF-19500/127-qualified Zener diode family, engineered specifically for voltage regulation in defense electronics, avionics, and space systems demanding extreme environmental resilience.
FAQ
What is the Zener voltage tolerance of the 1N749D-1E3?
The 1N749D-1E3 has a nominal Zener voltage of 4.3 V with a tolerance of ±1%, as indicated by the 'D' suffix in its nomenclature. This tight tolerance is verified per MIL-PRF-19500/127 test methods and applies at IZT = 20 mA and TJ = 25 °C. The 1N749D-1E3 maintains this specification across its full operating temperature range when properly derated.
Is the 1N749D-1E3 RoHS compliant?
Yes, the 1N749D-1E3 is RoHS compliant, as confirmed by the 'e3' suffix in its part number. This denotes RoHS-compliant matte-tin plating on the leads, meeting EU Directive 2011/65/EU. Note that RoHS compliance applies only to the commercial-grade version; JANTXV-qualified units may use tin-lead plating unless explicitly ordered with e3.
What does the '1E3' suffix mean in 1N749D-1E3?
The '1E3' suffix in 1N749D-1E3 breaks down as follows: '-1' indicates the JAN/JANTX/JANTXV qualification level per MIL-PRF-19500/127, and 'E3' specifies RoHS-compliant matte-tin plating. Together, they identify a JANTXV-qualified, RoHS-compliant variant of the 1N749D series, distinct from non-RoHS or commercial-only versions.
What is the maximum power dissipation for the 1N749D-1E3?
The 1N749D-1E3 has an average rated power dissipation of 500 mW when measured at TL = +50 °C with 0.375 inch lead length from the body. It linearly derates to zero at +175 °C. When mounted on a PCB, its rating drops to 400 mW at TA = +55 °C, per Figure 2 in T4-LDS-0288 Rev. 1. Thermal resistance junction-to-lead is 250 °C/W.
How is polarity marked on the 1N749D-1E3?
The 1N749D-1E3 uses a single black cathode band to indicate polarity, consistent with DO-35 package standards. The banded end is the cathode and must be held at a higher potential than the unmarked (anode) end for proper Zener regulation. This marking is visible on the glass body and is verified per MIL-STD-750 Method 2015 visual inspection requirements.
1N749D-1E3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 4.3 V
- Tolerance:
- ±1%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 22 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AH (DO-35)
1N749D-1E3 FAQ
1.How can I place an order for 1N749D-1E3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N749D-1E3 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 1N749D-1E3 reliable?
The price and inventory of 1N749D-1E3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N749D-1E3 is usually 5 days.
3.What payment methods are accepted for 1N749D-1E3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N749D-1E3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N749D-1E3?
1N749D-1E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N749D-1E3 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 1N749D-1E3?
For technical support, including 1N749D-1E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N749D-1E3 requirements.
6.How does Aetrix verify that 1N749D-1E3 is sourced from the original manufacturer or authorized distributors?
All 1N749D-1E3 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 1N749D-1E3 meets industry standards.
7.What is the process for return or replacement of 1N749D-1E3?
All 1N749D-1E3 units undergo pre-shipment inspection (PSI). If there is an issue with 1N749D-1E3, 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 1N749D-1E3 part is unused and in its original packaging.
Return procedure for 1N749D-1E3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N749D-1E3 Tags
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