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Microchip Technology JANTX1N4978DUS/TR
- Part No.:
- JANTX1N4978DUS/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
JANTX1N4978DUS/TR.pdf
- Description:
- DIODE ZENER 68V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:5,291
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Product details
Overview
JANTX1N4978DUS/TR from Microsemi is a military-qualified, voidless hermetically sealed glass Zener diode rated for 5 W power dissipation at 140 °C end-cap temperature, with nominal Zener voltage of 68 V ±2% (D suffix), dynamic impedance of 50 Ω at 20 mA test current, and operating junction temperature range from –65 °C to +175 °C. It serves as a precision voltage reference and overvoltage clamp in high-reliability aerospace power conditioning circuits.
For engineers reviewing the JANTX1N4978DUS/TR datasheet, JANTX1N4978DUS/TR pinout, JANTX1N4978DUS/TR application, or JANTX1N4978DUS/TR equivalent, this part delivers verified MIL-PRF-19500/356 Class JANTX performance, radiation-hardened construction, and stable regulation across extreme thermal and transient stress conditions typical in satellite power bus supervision and avionics voltage stabilization.
Technical Context
This device belongs to the 1N4954US–1N4996US family of surface-mount Zener regulators, employing a tungsten-slug glass package with triple-layer passivation and Category I metallurgical bonds. Its breakdown mechanism is optimized for low dynamic impedance and minimal voltage drift under pulsed surge loads up to 18.7 A (8.3 ms square wave).
It operates with a forward voltage of 1.50 V at 1.0 A and exhibits a temperature coefficient of +0.100 %/°C at IZT, enabling predictable biasing in wide-temperature-range analog references. Reverse leakage remains ≤2 μA at 51.7 V, supporting low-power standby regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 68 V ±2% at 20 mA - provides precise clamping threshold for 72 V nominal bus protection |
| Power Dissipation | 5 W @ TEC = 140 °C - supports continuous regulation in conduction-cooled avionics enclosures |
| Dynamic Impedance ZZ | 50 Ω @ IZT = 20 mA - ensures <1.0 V output variation across 5–10 mA load shifts |
| Max Junction Temp | –65 °C to +175 °C - enables deployment in unheated satellite bays and engine-mounted controllers |
| Thermal Resistance | 7 °C/W junction-to-end-cap - allows direct thermal path to chassis without heatsink |
| Surge Current IZSM | 18.7 A (8.3 ms) - withstands lightning-induced transients per DO-160 Section 22 Level 3 |
| Reverse Leakage IR | ≤2 μA @ 51.7 V - minimizes quiescent current drain in battery-backed systems |
Pinout & Package
Package: Hermetically sealed voidless glass "E" package (also designated D-5B), with copper end caps finished in Sn/Pb, cathode indicated by band, weight 539 mg, tape-and-reel compliant per EIA-481-B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential rail; accepts 1.5 V drop at 1 A during forward bias |
| Cathode | Zener breakdown terminal | Marked with band; referenced to system ground or regulated rail for voltage clamping |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates internal moisture ingress and long-term parameter drift in vacuum or humid environments |
| Category I metallurgical bond | Ensures mechanical integrity under 20,000 g shock and 20 g RMS vibration per MIL-STD-883 Method 2007 |
| Nonsensitive to ESD | Withstands ≥4 kV HBM per MIL-STD-750 Method 1020 without parameter shift or failure |
| Radiation hardness | Qualified to 100 krad(Si) TID per MicroNote 050 - suitable for low-earth orbit missions |
| Triple-layer passivation | Prevents surface leakage and ion migration under high humidity and bias stress |
Applications
| Aerospace Power Bus Protection | Avionics Voltage Reference |
|---|---|
|
Use Scenario: Clamping transient overvoltages on 28 V DC aircraft distribution buses during generator load dump events. IC Role / Device Role / Timing Role: Zener diode acting as shunt regulator and crowbar element in parallel with primary DC-DC converter output. Use Value: Withstands 18.7 A surge for 8.3 ms and maintains 68 V clamping threshold within ±2%, preventing downstream LRU damage. |
Use Scenario: Providing stable bias voltage for analog-to-digital converter reference buffers in flight control computers. IC Role / Device Role / Timing Role: Precision Zener reference source with low dynamic impedance and tight 2% tolerance. Use Value: Delivers 68 V reference with <50 Ω AC impedance and <0.1%/°C tempco, reducing ADC gain error across –55 °C to +125 °C. |
| Satellite Battery Management | Military Radar Power Supply |
|
Use Scenario: Overvoltage protection for Li-ion battery packs in CubeSat EPS subsystems exposed to solar array transients. IC Role / Device Role / Timing Role: Standby-mode Zener clamp activated only during fault conditions above 68 V. Use Value: Draws ≤2 μA leakage at 51.7 V, preserving battery life during multi-year orbital missions with no maintenance. |
Use Scenario: Regulating auxiliary supply rails in GaN-based radar transmitter modules operating at elevated ambient temperatures. IC Role / Device Role / Timing Role: High-temperature-stable Zener shunt regulator mounted directly to aluminum heat spreader. Use Value: Maintains regulation from –65 °C to +175 °C with 7 °C/W thermal resistance, eliminating need for active thermal management. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| JANTXV1N4978DUS/TR | Higher screening level (JANTXV vs JANTX); tighter parametric limits on ZZ and ΔVZ; qualified to MIL-PRF-19500/356 Class JANTXV | Required for mission-critical flight software power domains where single-point failure must be avoided | Select when full JANTXV screening and enhanced burn-in are mandated by system FMEA |
| 1N4978US | Commercial-grade version; no MIL-PRF-19500 qualification; same electrical specs but relaxed environmental testing | Suitable for ground-test equipment or non-flight prototypes where cost and lead time are prioritized | Choose for development labs or non-mission hardware where radiation hardness and extended temp range are not required |
Compared with JANTX1N4978DUS/TR, JANTXV1N4978DUS/TR adds burn-in and parametric screening for zero-defect operation in launch-critical paths, while 1N4978US removes military screening entirely-retaining identical Zener characteristics but sacrificing reliability assurance for cost-sensitive prototyping.
Availability
JANTX1N4978DUS/TR is available at Aetrix Electronics and suitable for aerospace power bus protection, avionics voltage reference, and satellite battery management requiring stable component supply under extended temperature cycling and radiation exposure.
Supply support for JANTX1N4978DUS/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 deep expertise in radiation-hardened and hermetic packaging.
The JANTX1N4978DUS/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.
FAQ
What is the Zener voltage tolerance for JANTX1N4978DUS/TR?
JANTX1N4978DUS/TR has a nominal Zener voltage of 68 V with ±2% tolerance, indicated by the "D" suffix per Microsemi's standard coding. This tolerance is guaranteed over the full operating temperature range of –65 °C to +175 °C and applies at the specified test current of 20 mA. The JANTX1N4978DUS/TR meets MIL-PRF-19500/356 requirements for parameter stability under thermal and mechanical stress.
Is JANTX1N4978DUS/TR radiation hardened?
Yes, JANTX1N4978DUS/TR is inherently radiation hard per Microsemi MicroNote 050, qualified to 100 krad(Si) total ionizing dose (TID). Its voidless glass package and Category I metallurgical bond contribute to its resilience against displacement damage and single-event effects, making JANTX1N4978DUS/TR suitable for low-earth orbit satellite power systems.
What is the maximum surge current rating for JANTX1N4978DUS/TR?
JANTX1N4978DUS/TR is rated for a nonrepetitive peak Zener surge current (IZSM) of 18.7 A under an 8.3 ms square-wave pulse, as defined in the Microsemi SD44A datasheet. This rating reflects its ability to absorb transient energy without degradation, critical for DO-160 Section 22 compliance in airborne equipment.
Does JANTX1N4978DUS/TR require derating above 140 °C?
Yes, JANTX1N4978DUS/TR must be derated linearly above an end-cap temperature (TEC) of 140 °C, reaching zero power dissipation at +175 °C. Derating slope is –35.7 mW/°C, calculated from 5 W / (175 – 140) °C. This ensures safe operation in conduction-cooled avionics chassis where end-cap temperature is the dominant thermal metric-not ambient or junction temperature alone.
What does the "US" suffix indicate in JANTX1N4978DUS/TR?
The "US" suffix in JANTX1N4978DUS/TR denotes the surface-mount "E" (D-5B) glass package with hermetically sealed voidless construction and copper end caps. It distinguishes this variant from axial-leaded equivalents (e.g., JANTX1N4978D) and confirms compliance with MIL-PRF-19500/356 for surface-mount assembly in high-reliability PCBs.
JANTX1N4978DUS/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):
- 68 V
- Tolerance:
- ±1%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 50 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 51.7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 1 A
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- Military
- Qualification:
- MIL-PRF-19500/356
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- E-MELF
JANTX1N4978DUS/TR FAQ
1.How can I place an order for JANTX1N4978DUS/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for JANTX1N4978DUS/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 JANTX1N4978DUS/TR reliable?
The price and inventory of JANTX1N4978DUS/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for JANTX1N4978DUS/TR is usually 5 days.
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Once your JANTX1N4978DUS/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 JANTX1N4978DUS/TR?
For technical support, including JANTX1N4978DUS/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your JANTX1N4978DUS/TR requirements.
6.How does Aetrix verify that JANTX1N4978DUS/TR is sourced from the original manufacturer or authorized distributors?
All JANTX1N4978DUS/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 JANTX1N4978DUS/TR meets industry standards.
7.What is the process for return or replacement of JANTX1N4978DUS/TR?
All JANTX1N4978DUS/TR units undergo pre-shipment inspection (PSI). If there is an issue with JANTX1N4978DUS/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 JANTX1N4978DUS/TR part is unused and in its original packaging.
Return procedure for JANTX1N4978DUS/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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