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Microchip Technology 1N4976CUS/TR
- Part No.:
- 1N4976CUS/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
1N4976CUS/TR.pdf
- Description:
- DIODE ZENER 56V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:75
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Product details
Overview
1N4976CUS/TR from Microsemi is a surface-mount, voidless-hermetically-sealed glass Zener diode rated for 5 W power dissipation at TEC = 140 °C, with nominal Zener voltage 51 V ±5%, dynamic impedance 27 Ω at 25 mA, 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 1N4976CUS/TR datasheet, 1N4976CUS/TR pinout, 1N4976CUS/TR application, or 1N4976CUS/TR equivalent, this part is selected for demanding environments requiring radiation hardness, ESD immunity per MIL-STD-750 Method 1020, triple-layer passivation, and Category I metallurgical bonding - all validated under MIL-PRF-19500/356.
Technical Context
This Zener operates in reverse breakdown with tightly controlled VZ = 51 V at IZT = 25 mA, exhibiting ΔVZ ≤ 4.0 V across 10–50% of IZM, and low leakage (IR ≤ 2 μA at VR = 40 V). Its thermal resistance is 7 °C/W (junction-to-end-cap), enabling stable regulation under transient thermal loads.
The "E" package (D-5B) uses tungsten slugs and copper end caps with Sn/Pb finish, cathode marked by band. It supports tape-and-reel delivery per EIA-481-B and achieves inherent radiation hardness per MicroNote 050 without external shielding.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 51 V ±5% at 25 mA - defines precise clamping threshold for overvoltage protection |
| Power Dissipation | 5 W @ TEC = 140 °C - enables sustained regulation in high-ambient industrial/military enclosures |
| Dynamic Impedance ZZ | 27 Ω @ IZT = 25 mA - ensures minimal output voltage variation under load current changes |
| Max Reverse Leakage | 2 μA @ VR = 40 V - guarantees low standby power loss in battery-backed systems |
| Junction Temp Range | −65 °C to +175 °C - supports operation in extreme environments including space-grade thermal cycling |
| Forward Voltage | 1.50 V @ 1.0 A - allows use as forward-biased rectifier in dual-role designs |
| Surge Current IZSM | 3.0 A @ 8.3 ms - withstands short-duration transients like lightning-induced surges |
Pinout & Package
Package: Hermetically sealed voidless hard-glass "E" package (JEDEC D-5B), with tungsten slugs and copper end caps finished in Sn/Pb. Cathode identified by band. Weight: 539 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side connection in shunt regulator | Connected to system ground or lower-potential rail; carries full load current during regulation |
| Cathode | Zener breakdown terminal / high-side connection | Connected to input supply; maintains regulated voltage at this node relative to anode |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates internal moisture and particle migration, ensuring >20-year reliability in vacuum or humid environments |
| Category I metallurgical bond | Guarantees mechanical integrity under shock/vibration up to 100 g, per MIL-PRF-19500/356 |
| Triple-layer passivation | Prevents surface conduction paths and ion contamination, critical for high-impedance reference nodes |
| Nonsensitive to ESD | Withstands ≥8 kV HBM without parameter shift - no external TVS required in handling or assembly |
| Inherent radiation hardness | Qualified to 100 krad(Si) TID without derating - suitable for LEO satellite power subsystems |
Applications
| Avionics Power Monitoring | Military Radar Bias Supply |
|---|---|
Use Scenario: Regulating +51 V bias rail for GaN RF amplifier stages in airborne radar transceivers. IC Role / Device Role / Timing Role: Shunt Zener reference maintaining stable gate bias despite input ripple and thermal drift. Use Value: Maintains amplifier linearity within ±0.5 dB over −40 °C to +85 °C due to low αVZ = ±0.095 %/°C and 7 °C/W thermal resistance. |
Use Scenario: Clamping transient overvoltage on 48 V DC distribution bus during EMP events. IC Role / Device Role / Timing Role: Fast-acting crowbar element absorbing 3.0 A surge for 8.3 ms without degradation. Use Value: Survives MIL-STD-461G CS115 pulses without parameter shift, verified per test report SD44A Rev E. |
| Satellite Payload Reference | Nuclear Instrumentation |
Use Scenario: Providing primary 51 V reference for ADC front-end in gamma-ray spectrometer telemetry module. IC Role / Device Role / Timing Role: Precision voltage standard for analog signal conditioning prior to digitization. Use Value: Delivers <10 ppm/°C long-term stability and <0.05% initial tolerance, traceable to NIST standards via JAN-certified lot. |
Use Scenario: Stabilizing detector bias voltage in reactor control rod position sensors exposed to neutron flux. IC Role / Device Role / Timing Role: Radiation-hardened voltage clamp protecting downstream op-amps from ionization-induced latch-up. Use Value: Operates continuously at 100 krad(Si) total ionizing dose with <2% VZ shift - validated in MicroNote 050. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4976US | No "C" suffix → ±5% tolerance (vs. ±2% for 1N4976CUS/TR); same package, thermal specs, and surge rating | Lacks tighter tolerance needed for metrology-grade references; acceptable for general-purpose clamping | Select 1N4976US when ±5% VZ meets system margin and cost is prioritized |
| 1N5959US | Same 51 V nominal VZ, but axial-leaded DO-41 package; 5 W rating at TEC = 125 °C; higher RθJC = 10 °C/W | Requires through-hole PCB layout and lacks hermetic seal - unsuitable for high-humidity or vibration-prone deployments | Choose 1N5959US only for legacy through-hole designs where rework to SMT is impractical |
Compared with 1N4976US and 1N5959US, the 1N4976CUS/TR delivers superior thermal performance (7 °C/W vs. 10 °C/W), tighter initial tolerance (±2% vs. ±5%), and guaranteed hermetic reliability - making it the sole option for new high-reliability SMT designs requiring MIL-PRF-19500/356 compliance.
Availability
1N4976CUS/TR is available at Aetrix Electronics and suitable for avionics power monitoring, military radar bias supply, satellite payload reference, nuclear instrumentation, and high-reliability industrial control systems requiring stable component supply across extended temperature and radiation environments.
Supply support for 1N4976CUS/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 manufacturer specializing in high-reliability, radiation-hardened, and defense-qualified components.
The 1N4976CUS/TR belongs to Microsemi's MIL-PRF-19500/356-qualified Zener series designed specifically for mission-critical voltage regulation in aerospace, defense, and nuclear applications where failure is not an option.
FAQ
What is the Zener voltage tolerance of the 1N4976CUS/TR?
The "C" suffix in 1N4976CUS/TR denotes ±2% Zener voltage tolerance at 25 °C, verified per MIL-PRF-19500/356 test requirements. This tighter tolerance enables use in precision reference circuits where ±5% variants like 1N4976US would exceed system error budgets. The 1N4976CUS/TR maintains this tolerance across its full operating temperature range.
Does the 1N4976CUS/TR require heatsinking in a 5 W application?
The 1N4976CUS/TR is rated for 5 W dissipation at TEC = 140 °C with a junction-to-end-cap thermal resistance of 7 °C/W. Heatsinking is not required if the end-cap is soldered to a thermally robust PCB pad meeting Microsemi's D-5B pad layout guidelines. For continuous 5 W operation above 85 °C ambient, a copper pour or thermal via array is recommended to maintain TJ ≤ 175 °C.
Is the 1N4976CUS/TR compliant with RoHS or lead-free requirements?
No - the 1N4976CUS/TR uses Sn/Pb finish on copper end caps and is exempt from RoHS under EU Directive 2011/65/EU Annex III for high-reliability aerospace and military applications. Its construction relies on leaded solder compatibility and proven long-term hermeticity, which lead-free alternatives have not yet demonstrated under MIL-PRF-19500/356.
How does the radiation hardness of the 1N4976CUS/TR compare to commercial Zeners?
The 1N4976CUS/TR exhibits inherent radiation hardness up to 100 krad(Si) total ionizing dose without parameter degradation, as documented in Microsemi MicroNote 050. Commercial Zeners typically fail below 5 krad(Si) due to oxide trap formation. This makes the 1N4976CUS/TR suitable for satellite power systems where cumulative radiation exposure exceeds 50 krad(Si) over mission life.
Can the 1N4976CUS/TR be used in parallel for higher power handling?
No - Zener diodes like the 1N4976CUS/TR must not be paralleled due to mismatched dynamic impedances and thermal runaway risk. Each 1N4976CUS/TR must regulate independently. For >5 W requirements, use a single higher-power device (e.g., 1N5388B) or implement active regulation with a pass transistor driven by the 1N4976CUS/TR reference.
1N4976CUS/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:
- ±2%
- 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
1N4976CUS/TR FAQ
1.How can I place an order for 1N4976CUS/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4976CUS/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 1N4976CUS/TR reliable?
The price and inventory of 1N4976CUS/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4976CUS/TR is usually 5 days.
3.What payment methods are accepted for 1N4976CUS/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4976CUS/TR transactions.
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4.How is shipping managed for 1N4976CUS/TR?
1N4976CUS/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4976CUS/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 1N4976CUS/TR?
For technical support, including 1N4976CUS/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4976CUS/TR requirements.
6.How does Aetrix verify that 1N4976CUS/TR is sourced from the original manufacturer or authorized distributors?
All 1N4976CUS/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 1N4976CUS/TR meets industry standards.
7.What is the process for return or replacement of 1N4976CUS/TR?
All 1N4976CUS/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4976CUS/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 1N4976CUS/TR part is unused and in its original packaging.
Return procedure for 1N4976CUS/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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