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Microchip Technology 1N4977US/TR
- Part No.:
- 1N4977US/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
1N4977US/TR.pdf
- Description:
- DIODE ZENER 62V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:101
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Product details
Overview
1N4977US/TR from Microsemi is a surface-mount, voidless-hermetically-sealed glass Zener diode rated for 5 W power dissipation at TEC = 125 °C, with nominal Zener voltage 62 V ±5%, dynamic impedance 42 Ω at 20 mA test current, and operating junction temperature range −65 °C to +175 °C. It serves as a precision voltage reference or overvoltage clamp in high-reliability military and aerospace power regulation circuits.
For engineers reviewing the 1N4977US/TR datasheet, 1N4977US/TR pinout, 1N4977US/TR application, or 1N4977US/TR equivalent, key selection criteria include its hermetic glass package, Category III metallurgical bond, radiation-hardened construction per MicroNote 050, and compliance with MIL-PRF-19500/356 for JAN/JANTXV grades.
Technical Context
This device operates in reverse breakdown mode with tightly controlled Zener voltage regulation across wide current (10%–50% of IZM) and temperature ranges. Its 42 Ω dynamic impedance at IZT = 20 mA ensures stable regulation under varying load conditions.
The "E" package (D-5B) uses tungsten slugs and copper end caps with Sn/Pb finish, enabling direct solder attachment without adhesive. Thermal resistance is 10 °C/W junction-to-end-cap, supporting high-temperature operation up to 175 °C junction.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 62 V ±5% at IZT = 20 mA - defines regulated output voltage tolerance in reference and clamp applications |
| Power Dissipation | 5 W @ TEC = 125 °C - maximum continuous thermal load before derating begins |
| Dynamic Impedance ZZ | 42 Ω @ IZT = 20 mA - low AC impedance ensures minimal voltage shift under ripple or transient load changes |
| Max Reverse Leakage IR | 2 μA @ VR = 47.1 V - ultra-low leakage preserves accuracy in high-impedance bias networks |
| Junction Temp Range | −65 °C to +175 °C - enables deployment in extreme-environment avionics and downhole electronics |
| Thermal Resistance θJC | 10 °C/W junction-to-end-cap - determines required heatsinking for sustained 5 W operation |
| Surge Current IZSM | 2.5 A @ 8.3 ms - withstands short-duration transients without degradation |
Pinout & Package
The 1N4977US/TR uses the "E" package (also designated D-5B), a surface-mount hermetic glass case with two axial end-cap terminals. Cathode is marked by a band on the glass body. End caps are copper with Sn/Pb finish and designed for reflow soldering directly to PCB pads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side reference node | Connected to circuit ground or lower potential; carries forward current up to 1.0 A |
| Cathode | Zener breakdown terminal / regulated output node | Connected to input supply; maintains 62 V reference relative to anode during reverse bias |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates internal moisture and particle contamination, ensuring long-term parametric stability in vacuum or humid environments |
| Category III metallurgical bond | Provides mechanical robustness against thermal cycling and vibration stress in aerospace-grade assemblies |
| MIL-PRF-19500/356 qualification | Validates performance for JAN, JANTX, JANTXV, and JANS grades-required for defense and space programs |
| Radiation hardness | Documented in Microsemi MicroNote 050; suitable for low-dose-rate TID environments without shielding |
| Nonsensitive to ESD | Complies with MIL-STD-750 Method 1020; no special handling required during assembly |
Applications
| Aerospace Power Conditioning | Defense System Voltage Reference |
|---|---|
Use Scenario: Regulating auxiliary bus voltage in satellite power distribution units exposed to thermal cycling and radiation. IC Role / Device Role / Timing Role: Zener diode providing primary 62 V reference for DC-DC converter feedback and overvoltage protection. Use Value: Hermetic seal and −65 °C to +175 °C operation ensure reliability across orbital temperature extremes without parameter drift. |
Use Scenario: Precision voltage clamping in radar transmitter bias supplies where failure must be avoided. IC Role / Device Role / Timing Role: Overvoltage protection element shunting excess energy during pulse-mode operation. Use Value: 2.5 A surge rating and 42 Ω dynamic impedance limit voltage overshoot to <±0.1 V during 8.3 ms transients. |
| Downhole Oilfield Instrumentation | Avionics Sensor Excitation |
Use Scenario: Stabilizing excitation voltage for piezoresistive pressure sensors in deep-well drilling tools. IC Role / Device Role / Timing Role: Fixed-voltage reference source maintaining sensor bridge bias under high ambient temperature. Use Value: 10 °C/W thermal resistance and 175 °C max junction temperature enable operation at 150 °C ambient without derating. |
Use Scenario: Providing calibrated 62 V bias for ionization smoke detectors in aircraft cabin systems. IC Role / Device Role / Timing Role: High-stability Zener reference feeding analog front-end comparators. Use Value: ±5% initial tolerance and <2 μA leakage at 47.1 V ensure consistent trip-point accuracy over 10-year service life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4977US | No /TR suffix; bulk packaging instead of tape-and-reel; identical electrical and mechanical specs | Same use cases but requires manual loading; unsuitable for high-speed SMT lines | Select 1N4977US/TR for automated pick-and-place; choose 1N4977US only for prototyping or low-volume hand-soldered builds |
| 1N4977 | Non-US variant: axial-leaded TO-204AA (DO-4) package; same VZ, IZT, and ratings but different thermal path and mounting | Requires through-hole PCB layout; higher thermal resistance (12 °C/W) limits sustained 5 W use | Choose 1N4977 only when legacy board design mandates axial leads or when rework accessibility outweighs surface-mount density benefits |
Compared with 1N4977US/TR, the 1N4977US offers identical performance in bulk form but lacks tape-and-reel logistics support, while the axial 1N4977 trades SMT compatibility for easier manual replacement-neither is pin-compatible due to differing packages and terminations.
Availability
1N4977US/TR is available at Aetrix Electronics and suitable for aerospace power conditioning, defense system voltage reference, and downhole oilfield instrumentation requiring stable component supply across extended temperature and radiation environments.
Supply support for 1N4977US/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) designs high-reliability analog and mixed-signal semiconductors for aerospace, defense, and industrial markets, with emphasis on radiation-hardened and hermetically sealed components.
The 1N4977US/TR belongs to Microsemi's military-qualified Zener series built for MIL-PRF-19500/356 compliance, targeting applications where failure is not tolerable-including satellite subsystems and critical avionics.
FAQ
What is the Zener voltage tolerance of the 1N4977US/TR?
The 1N4977US/TR has a nominal Zener voltage of 62 V with a standard tolerance of ±5%, as specified in the Electrical Characteristics table at IZT = 20 mA. Tighter tolerances (e.g., ±2% or ±1%) require different suffixes (C or D) and are not applicable to the /TR variant.
Does the 1N4977US/TR meet MIL-PRF-19500/356 requirements?
Yes-the 1N4977US/TR is qualified to MIL-PRF-19500/356 and supports JAN, JANTX, JANTXV, and JANS screening levels. Its Category III metallurgical bond, voidless glass seal, and −65 °C to +175 °C operation are all verified per this specification.
What is the maximum continuous Zener current for the 1N4977US/TR?
The maximum continuous Zener current IZM for the 1N4977US/TR is 930 mA, calculated from PD = 5 W and VZ = 62 V. This value assumes operation at TEC = 125 °C and linear derating to zero at 175 °C.
Is the 1N4977US/TR radiation hardened?
Yes-the 1N4977US/TR is inherently radiation hard, as documented in Microsemi MicroNote 050. It exhibits low total ionizing dose (TID) sensitivity and is routinely used in low-earth orbit and high-altitude platforms without additional shielding.
What package type does the 1N4977US/TR use?
The 1N4977US/TR uses the "E" package (also known as D-5B): a surface-mount, hermetically sealed voidless glass case with tungsten slugs and copper end caps finished with Sn/Pb. It is not compatible with plastic SOD-123 or DO-214AC packages.
1N4977US/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- SQ-MELF, E
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 62 V
- Tolerance:
- ±5%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 42 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 47.1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 1 A
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- E-MELF
1N4977US/TR FAQ
1.How can I place an order for 1N4977US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4977US/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 1N4977US/TR reliable?
The price and inventory of 1N4977US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4977US/TR is usually 5 days.
3.What payment methods are accepted for 1N4977US/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4977US/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4977US/TR?
1N4977US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4977US/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 1N4977US/TR?
For technical support, including 1N4977US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4977US/TR requirements.
6.How does Aetrix verify that 1N4977US/TR is sourced from the original manufacturer or authorized distributors?
All 1N4977US/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 1N4977US/TR meets industry standards.
7.What is the process for return or replacement of 1N4977US/TR?
All 1N4977US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4977US/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 1N4977US/TR part is unused and in its original packaging.
Return procedure for 1N4977US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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