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Microchip Technology 1N4979US/TR
- Part No.:
- 1N4979US/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
1N4979US/TR.pdf
- Description:
- DIODE ZENER 75V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:101
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Product details
Overview
1N4979US/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 of 75 V at 20 mA test current, ±5% tolerance, and dynamic impedance of 55 Ω at IZT; used in high-reliability voltage regulation for aerospace power conditioning and radiation-hardened instrumentation.
For engineers reviewing the 1N4979US/TR datasheet, 1N4979US/TR pinout, 1N4979US/TR application, or 1N4979US/TR equivalent, this part supports critical voltage reference stability across -65 °C to +175 °C, delivers 2 μA max reverse leakage at 60 V, maintains <±0.1%/°C temperature coefficient, and meets MIL-PRF-19500/356 Class JANTXV requirements.
Technical Context
This device operates as a precision shunt voltage regulator in breakdown mode, with metallurgical Category III internal bonding and triple-layer passivation ensuring long-term parametric stability under thermal cycling and radiation exposure. Its voidless-glass hermetic seal eliminates moisture ingress and interfacial delamination risks common in epoxy-packaged Zeners.
The 1N4979US/TR exhibits low dynamic impedance (55 Ω) at 20 mA, enabling tight regulation over wide load-current variations, and supports surge currents up to 2.0 A (8.3 ms square wave) without degradation - critical for transient suppression in avionics power rails.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 75 V ±5% at IZT = 20 mA - defines stable regulation point for 75-V reference designs |
| Power Dissipation | 5 W @ TEC = 125 °C - enables high-power regulation without external heatsinking in compact layouts |
| Dynamic Impedance ZZ | 55 Ω @ IZT - ensures minimal output voltage shift under load transients |
| Reverse Leakage IR | 2 μA max @ VR = 60 V - guarantees low standby power loss in battery-backed systems |
| Temp Coefficient αVZ | ±0.100 %/°C - provides predictable drift behavior for temperature-compensated references |
| Max Continuous Current IZM | 2.0 A - sets safe DC operating limit for sustained regulation duty |
| Surge Current IZSM | 2.0 A (8.3 ms sq. wave) - withstands lightning-induced transients per DO-160 Section 22 |
Pinout & Package
Package: Hermetically sealed voidless hard glass case with tungsten slugs; end caps are copper with Sn/Pb finish; polarity indicated by cathode band; weight 539 mg; tape-and-reel compliant per EIA-481-B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias; connected to ground or low-side reference node in shunt regulator configuration | Accepts up to 1.0 A forward current at ≤1.5 V drop - supports bidirectional clamping when paired with series resistor |
| Cathode | Regulated output node in reverse breakdown; referenced to system ground via series input resistor | Delivers stable 75 V output with <55 Ω AC impedance - forms precision shunt reference for feedback loops |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates moisture-induced parameter shift and bond-wire corrosion over 20+ year field life |
| Category III metallurgical bond | Ensures mechanical integrity under shock/vibration >100 g and thermal cycling from -65 °C to +175 °C |
| MIL-PRF-19500/356 qualification | Validates reliability for JANTXV-grade deployment in flight-critical subsystems without burn-in screening |
| Nonsensitive to ESD (MIL-STD-750 Method 1020) | Withstands ≥4 kV HBM without parameter degradation - simplifies handling and assembly in cleanrooms |
| Radiation hardness | Retains electrical performance after total ionizing dose ≥100 krad(Si), per MicroNote 050 |
Applications
| Aerospace Power Conditioning | Avionics Reference Supply |
|---|---|
Use Scenario: Regulating unregulated 100–120 VDC bus in satellite power distribution units under thermal vacuum conditions. IC Role / Device Role / Timing Role: Shunt voltage regulator providing stable 75 V reference for DC-DC converter feedback networks. Use Value: Maintains <±1% output accuracy across -65 °C to +175 °C and survives 100 krad(Si) TID exposure without recalibration. |
Use Scenario: Generating precise bias voltage for analog-to-digital converter front-end amplifiers in inertial measurement units. IC Role / Device Role / Timing Role: Low-noise Zener reference source replacing IC-based references where radiation immunity is mandatory. Use Value: Delivers 75 V with <2 μA leakage at 60 V, minimizing input offset drift in high-impedance sensor interfaces. |
| Defense Radar Bias Supply | Nuclear Instrumentation |
Use Scenario: Stabilizing high-voltage bias for GaN RF power amplifier stages in ground-based radar transmitters. IC Role / Device Role / Timing Role: Primary shunt regulator in multi-stage HV supply, absorbing ripple and transient energy. Use Value: Withstands 2.0 A surge (8.3 ms) and dissipates 5 W continuously - replaces bulkier TO-204 packages with SMT footprint. |
Use Scenario: Providing calibrated reference voltage for gamma spectrometer pulse-height analyzers operating in reactor containment zones. IC Role / Device Role / Timing Role: Radiation-hardened voltage standard for gain calibration of photomultiplier tube signal chains. Use Value: Exhibits <±0.1%/°C tempco and zero parametric shift after neutron fluence >1 × 1014 n/cm². |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4979US | Same electrical specs and package; differs only in packaging format (bulk vs. tape-and-reel) | No functional difference; identical use in automated SMT assembly lines | Select 1N4979US/TR for pick-and-place compatibility and traceable reel lot control |
| 1N4979 | Same die and Zener characteristics; axial-leaded DO-41 package instead of surface-mount "E" (D-5B) glass | Requires through-hole mounting; unsuitable for high-density PCBs or reflow processes | Choose 1N4979 only for legacy board redesigns or manual prototyping where SMT is unavailable |
Compared with 1N4979US and 1N4979, the 1N4979US/TR offers full SMT process compatibility, tighter reel-based lot traceability, and identical radiation hardness - making it the preferred choice for new high-reliability aerospace designs requiring automated assembly.
Availability
1N4979US/TR is available at Aetrix Electronics and suitable for aerospace power conditioning, avionics reference supply, and defense radar bias supply requiring stable component supply with guaranteed long-term obsolescence management.
Supply support for 1N4979US/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 semiconductor components for aerospace, defense, and industrial applications, emphasizing radiation hardness, extended temperature operation, and military qualification.
The 1N4979US/TR belongs to Microsemi's legacy MIL-PRF-19500/356 qualified Zener series, engineered specifically for mission-critical voltage regulation where failure is not an option - including spaceflight power systems and nuclear instrumentation.
FAQ
What is the Zener voltage tolerance for 1N4979US/TR?
The 1N4979US/TR has a nominal Zener voltage of 75 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 different part number suffixes (C or D) not present in 1N4979US/TR. This tolerance applies at 20 mA test current and 25 °C ambient.
Does 1N4979US/TR meet MIL-PRF-19500/356 requirements?
Yes, the 1N4979US/TR is qualified to MIL-PRF-19500/356 as a JANTXV-grade device, confirmed in the official Microsemi SD44A datasheet. It undergoes full military screening including temperature cycling, hermeticity testing, and radiation hardness validation per MicroNote 050 - making it suitable for flight-critical avionics and defense electronics.
What is the maximum power dissipation for 1N4979US/TR?
The 1N4979US/TR is rated for 5 W power dissipation at an end-cap temperature (TEC) of 125 °C. Power must be linearly derated above that temperature, reaching zero at 175 °C junction temperature. This rating assumes proper PCB copper area and thermal path design per the "E" package thermal impedance of 10 °C/W junction-to-end-cap.
Is 1N4979US/TR radiation hardened?
Yes, the 1N4979US/TR is inherently radiation hard, with documented performance retention after total ionizing dose (TID) exposure ≥100 krad(Si), as described in Microsemi MicroNote 050. Its voidless-glass construction and Category III metallurgical bonds contribute to this hardness - verified across the full 1N4954US–1N4996US family.
What is the reverse leakage current specification for 1N4979US/TR?
The 1N4979US/TR has a maximum reverse leakage current (IR) of 2 μA at VR = 60 V and 25 °C, per the SD44A datasheet. This low leakage ensures minimal quiescent power draw in battery-backed or low-power instrumentation circuits, supporting long-term stability in high-impedance reference applications.
1N4979US/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):
- 75 V
- Tolerance:
- ±5%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 55 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 56 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
1N4979US/TR FAQ
1.How can I place an order for 1N4979US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4979US/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 1N4979US/TR reliable?
The price and inventory of 1N4979US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4979US/TR is usually 5 days.
3.What payment methods are accepted for 1N4979US/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4979US/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4979US/TR?
1N4979US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4979US/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 1N4979US/TR?
For technical support, including 1N4979US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4979US/TR requirements.
6.How does Aetrix verify that 1N4979US/TR is sourced from the original manufacturer or authorized distributors?
All 1N4979US/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 1N4979US/TR meets industry standards.
7.What is the process for return or replacement of 1N4979US/TR?
All 1N4979US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4979US/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 1N4979US/TR part is unused and in its original packaging.
Return procedure for 1N4979US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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