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Microchip Technology 1N4976US/TR
- Part No.:
- 1N4976US/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
1N4976US/TR.pdf
- Description:
- DIODE ZENER 56V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:16
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Product details
Overview
1N4976US/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 56 V ±5%, dynamic impedance 35 Ω at IZT = 20 mA, and reverse leakage ≤2 μA at 42.6 V - used in high-reliability voltage regulation and overvoltage protection circuits for aerospace power supplies.
For engineers reviewing the 1N4976US/TR datasheet, 1N4976US/TR pinout, 1N4976US/TR application, or 1N4976US/TR equivalent, key selection criteria include its MIL-PRF-19500/356 qualification, −65 °C to +175 °C operating temperature range, hermetic glass package with tungsten slugs, and Category III internal metallurgical bond - critical for radiation-hardened and extended-life systems.
Technical Context
This device operates as a precision voltage reference in breakdown mode, maintaining stable regulation across 10%–50% of IZM (ΔVZ ≤ 4.4 V), with low temperature coefficient (+0.095%/°C) and robust surge capability (14.4 A @ 8.3 ms). Its voidless-glass construction eliminates moisture ingress paths and supports long-term parametric stability under thermal cycling.
The 1N4976US/TR uses a two-terminal axial-symmetric geometry with cathode band marking, copper end caps with Sn/Pb finish, and EIA-481-B tape-and-reel packaging. It is not a junction-isolated semiconductor but a bulk Zener structure relying on avalanche breakdown above ~6 V, consistent with its 56 V rating and 35 Ω dynamic impedance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 56 V ±5% at IZT = 20 mA - defines regulated output voltage under nominal bias |
| Power Dissipation | 5 W @ TEC = 125 °C - sets maximum continuous thermal load without derating |
| Dynamic Impedance ZZ | 35 Ω at IZT = 20 mA - determines output voltage variation under load current changes |
| Reverse Leakage IR | ≤2 μA at VR = 42.6 V - ensures minimal standby power loss in high-impedance bias networks |
| Operating Temperature | −65 °C to +175 °C - enables deployment in extreme-environment avionics and downhole electronics |
| Thermal Resistance | 10 °C/W junction-to-end-cap - informs heatsinking requirements for sustained 5 W operation |
| Surge Current IZSM | 14.4 A (8.3 ms square wave) - supports transient overvoltage clamping in MIL-STD-1275-compliant systems |
Pinout & Package
Package: Hermetically sealed voidless hard glass case with tungsten slugs ("E" or "D-5B" outline); cathode indicated by band; copper end caps with Sn/Pb finish; weight 539 mg; tape-and-reel per EIA-481-B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-voltage reference node | Connected to circuit ground or lowest potential point during Zener regulation |
| Cathode | Breakdown voltage terminal / regulated output node | Provides stable 56 V reference when reverse-biased above VZ; marked by band |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates moisture-induced parameter drift and corrosion failure modes in humid or vacuum environments |
| Category III metallurgical bond | Ensures mechanical integrity and thermal cycle survivability up to 1000 cycles between −65 °C and +175 °C |
| MIL-PRF-19500/356 qualification | Validates compliance with military screening, testing, and traceability requirements for Class S (space-level) applications |
| Nonsensitive to ESD (MIL-STD-750 Method 1020) | Enables handling without special grounding protocols during board assembly and rework |
| Inherent radiation hardness | Supports total ionizing dose (TID) tolerance >100 krad(Si) without derating - verified per MicroNote 050 |
Applications
| Aerospace Power Bus Regulation | Downhole Instrumentation Reference |
|---|---|
|
Use Scenario: Stabilizing 56 V auxiliary rail in satellite power distribution units exposed to thermal vacuum and radiation. IC Role / Device Role / Timing Role: Zener diode acting as shunt voltage regulator and overvoltage clamp. Use Value: Maintains ±5% regulation across −65 °C to +175 °C while surviving 100 krad(Si) TID - eliminating need for active regulation circuitry. |
Use Scenario: Providing stable 56 V reference for pressure transducer excitation in oil/gas well logging tools. IC Role / Device Role / Timing Role: Precision voltage reference source in high-temperature analog front-end. Use Value: Delivers <2 μA leakage at 42.6 V and 175 °C - preserving measurement accuracy in millivolt-level sensor outputs. |
| Military Vehicle EMI Filter Clamp | Radiation-Hardened FPGA Configuration Supply |
|
Use Scenario: Clamping induced surges on 48 V vehicle power lines per MIL-STD-1275B. IC Role / Device Role / Timing Role: Transient voltage suppressor absorbing 14.4 A 8.3 ms surges. Use Value: Withstands repetitive 14.4 A surges without degradation - validated via MIL-PRF-19500/356 surge testing. |
Use Scenario: Biasing configuration EEPROMs and startup logic in rad-tolerant FPGAs aboard deep-space probes. IC Role / Device Role / Timing Role: Primary voltage reference for nonvolatile memory programming voltage generation. Use Value: Zero parametric shift after 100 krad(Si) exposure - enabling single-point calibration for mission-critical configuration data. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4976US | Same electrical specs and package; differs only in packaging format (bulk vs. tape/reel) | No functional difference; identical use in PCB assembly | Select 1N4976US/TR for automated SMT placement; choose 1N4976US for manual prototyping or low-volume hand-soldering |
| 1N5969US | 6.2 V Zener voltage, 220 mA IZM, 1.0 Ω ZZ, 10 °C/W thermal resistance - lower voltage, higher current, lower impedance | Suitable for 5–6 V logic supply regulation, not 56 V bus clamping | Use 1N5969US only where 6.2 V reference and sub-ohm impedance are required; not interchangeable with 1N4976US/TR |
Compared with 1N4976US/TR, the 1N4976US offers identical performance in bulk form but lacks tape-and-reel logistics; the 1N5969US serves entirely different voltage domains and cannot replace 1N4976US/TR in 56 V systems without redesigning bias networks and surge margins.
Availability
1N4976US/TR is available at Aetrix Electronics and suitable for aerospace power regulation, downhole instrumentation reference, and military vehicle EMI filtering requiring stable component supply across extended temperature and radiation environments.
Supply support for 1N4976US/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 components for defense, aerospace, and industrial markets, with emphasis on radiation-hardened, high-temperature, and hermetic solutions.
The 1N4976US/TR belongs to Microsemi's legacy MIL-PRF-19500/356-qualified Zener series, engineered specifically for voltage regulation in mission-critical systems where failure is not an option - including launch vehicles, satellites, and nuclear instrumentation.
FAQ
What is the Zener voltage tolerance for 1N4976US/TR?
The 1N4976US/TR has a nominal Zener voltage of 56 V with a standard tolerance of ±5%, as specified in the Microsemi SD44A datasheet. No suffix indicates this standard tolerance; tighter tolerances (e.g., ±2% or ±1%) require C or D suffixes, which do not apply to the 1N4976US/TR variant.
Is 1N4976US/TR qualified to MIL-PRF-19500/356?
Yes, the 1N4976US/TR is explicitly qualified to MIL-PRF-19500/356 per the manufacturer's documentation, supporting JAN, JANTX, JANTXV, and JANS screening levels. This qualification covers environmental testing, lot traceability, and process controls required for high-reliability defense and space applications.
What is the maximum continuous Zener current for 1N4976US/TR?
The maximum continuous Zener current (IZM) for 1N4976US/TR is 930 mA, calculated from its 5 W power rating and 56 V Zener voltage (P = V × I). This value is valid at TEC = 125 °C and must be linearly derated to zero at +175 °C per the datasheet's thermal curve.
Does 1N4976US/TR have radiation hardness certification?
Yes, the 1N4976US/TR exhibits inherent radiation hardness documented in Microsemi MicroNote 050, supporting total ionizing dose (TID) tolerance exceeding 100 krad(Si) without functional degradation or parametric shift - a design feature enabled by its voidless-glass hermetic construction and Category III metallurgical bond.
What is the thermal resistance junction-to-end-cap for 1N4976US/TR?
The thermal resistance (θJE) for 1N4976US/TR is 10 °C/W, as confirmed in the "Maximum Ratings" section of the SD44A datasheet. This value applies to the full 1N4954US–1N4996US family and directly informs heatsink sizing when operating continuously near 5 W dissipation.
1N4976US/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):
- 56 V
- Tolerance:
- ±5%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 35 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 42.6 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
1N4976US/TR FAQ
1.How can I place an order for 1N4976US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4976US/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 1N4976US/TR reliable?
The price and inventory of 1N4976US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4976US/TR is usually 5 days.
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Note: Certain payment methods may incur a processing fee.
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1N4976US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4976US/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 1N4976US/TR?
For technical support, including 1N4976US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4976US/TR requirements.
6.How does Aetrix verify that 1N4976US/TR is sourced from the original manufacturer or authorized distributors?
All 1N4976US/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 1N4976US/TR meets industry standards.
7.What is the process for return or replacement of 1N4976US/TR?
All 1N4976US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4976US/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 1N4976US/TR part is unused and in its original packaging.
Return procedure for 1N4976US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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