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Microchip Technology JANTX1N4978CUS/TR
- Part No.:
- JANTX1N4978CUS/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
JANTX1N4978CUS/TR.pdf
- Description:
- DIODE ZENER 68V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:8,532
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Product details
Overview
JANTX1N4978US/TR from Microsemi is a military-qualified, hermetically sealed surface-mount Zener diode with 68 V nominal zener voltage, 5 W power rating at 140 °C end-cap temperature, and ±5% tolerance. It delivers stable voltage regulation in high-reliability aerospace, defense, and downhole instrumentation systems where failure is unacceptable.
For engineers reviewing the JANTX1N4978US/TR datasheet, JANTX1N4978US/TR pinout, JANTX1N4978US/TR application, or JANTX1N4978US/TR equivalent, this part is selected for its voidless-glass construction, Category I metallurgical bond, -65 °C to +175 °C operating range, and radiation-hardened performance per MicroNote 050.
Technical Context
This Zener operates in reverse breakdown with tightly controlled dynamic impedance (50 Ω @ 20 mA) and low temperature coefficient (+0.100 %/°C). Its regulation stability is maintained across 10%–50% of maximum zener current (IZM = 2.2 A), with ΔVZ ≤ 5.5 V under those conditions.
The device uses a tungsten slug within a voidless hard-glass case, copper end caps with Sn/Pb finish, and cathode polarity marked by a band. Thermal resistance is 7 °C/W junction-to-end-cap, enabling reliable 5 W dissipation when mounted on thermally optimized PCBs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage (VZ) | 68 V @ IZT = 20 mA - defines precise regulation point for feedback loops and reference circuits |
| Power Dissipation (PZ) | 5 W @ TEC = 140 °C - requires thermal management via end-cap soldering to copper pour |
| Zener Impedance (ZZT) | 50 Ω @ 20 mA - ensures minimal output voltage variation under load transients |
| Max Reverse Leakage (IR) | 2 μA @ VR = 51.7 V - guarantees low standby current in precision bias networks |
| Operating Temperature | -65 °C to +175 °C - supports deployment in extreme environments without derating |
| Surge Current (IZSM) | 18.7 A @ 8.3 ms - withstands lightning-induced transients in avionics power rails |
| Temp Coefficient (αVZ) | +0.100 %/°C - enables predictable drift compensation in wide-temperature-range designs |
Pinout & Package
Package: Hermetically sealed voidless hard-glass "E" package (JEDEC DO-213AA), also designated D-5B. Case features tungsten slugs and copper end caps with Sn/Pb finish. Cathode indicated by band. Weight: 539 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side reference node | Connected to circuit ground or lowest potential point in shunt regulator topology |
| Cathode | Zener breakdown terminal / regulated output node | Provides stable 68 V reference when reverse-biased; must be routed with low-inductance trace |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates internal moisture and particle migration-critical for >20-year mission life in space-grade systems |
| Category I metallurgical bond | Ensures mechanical integrity under shock/vibration up to 100 g, per MIL-PRF-19500/356 |
| Triple-layer passivation | Prevents surface leakage and corrosion in high-humidity or salt-spray environments |
| Radiation hardness | Inherently tolerant to total ionizing dose (TID) per Microsemi MicroNote 050-no shielding required |
| ESD robustness | Qualified to MIL-STD-750 Method 1020-survives ≥4 kV HBM without parameter shift |
Applications
| Aerospace Power Conditioning | Downhole Telemetry Reference |
|---|---|
|
Use Scenario: Regulating auxiliary supply rails in satellite DC-DC converters exposed to thermal cycling and radiation. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable 68 V bias for error amplifiers and gate drivers. Use Value: Maintains regulation accuracy within ±5% over -65 °C to +175 °C, eliminating need for active compensation circuitry. |
Use Scenario: Precision voltage reference in high-temperature logging tools deployed at 200 °C wellbore depths. IC Role / Device Role / Timing Role: Zener-based reference for ADC front-end and sensor excitation circuitry. Use Value: Delivers <2 μA leakage at 51.7 V even after 1000-hour HTOL stress, ensuring long-term measurement fidelity. |
| Military Radar Bias Supply | Nuclear Instrumentation |
|
Use Scenario: Stabilizing collector supply for GaN RF power amplifier stages in airborne radar transceivers. IC Role / Device Role / Timing Role: Overvoltage clamp and voltage reference in pulsed high-power bias networks. Use Value: Withstands 18.7 A surge current at 8.3 ms, protecting amplifiers during RF switching transients. |
Use Scenario: High-stability reference in neutron detection pulse-height analyzers operating in reactor containment zones. IC Role / Device Role / Timing Role: Radiation-hardened voltage reference for charge-integration amplifiers. Use Value: No parametric shift after 100 krad(Si) TID exposure-enables calibration-free operation over full 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 |
|---|---|---|---|
| JANTXV1N4978US/TR | Higher screening level (JANTXV vs. JANTX); tighter test limits per MIL-PRF-19500/356 Class V | Required for Class V spaceflight programs with zero-defect reliability mandates | Select JANTXV1N4978US/TR only when mission-critical redundancy or extended burn-in is specified |
| 1N4978US | Commercial-grade version; no MIL-qualified screening, no radiation data, wider temp range not guaranteed | Suitable for industrial prototypes or non-mission-critical test equipment | Choose 1N4978US only for cost-sensitive development where military qualification is unnecessary |
Compared with JANTX1N4978US/TR, JANTXV1N4978US/TR adds Class V screening for ultra-high-reliability missions, while 1N4978US omits military qualification entirely-making JANTX1N4978US/TR the balanced choice for defense-grade production with verified radiation tolerance and thermal margin.
Availability
JANTX1N4978US/TR is available at Aetrix Electronics and suitable for aerospace power conditioning, downhole telemetry reference, and military radar bias supply requiring stable component supply across extended temperature and radiation environments.
Supply support for JANTX1N4978US/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 company specializing in high-reliability analog and mixed-signal components for aerospace, defense, and industrial markets.
JANTX1N4978US/TR belongs to Microsemi's military-qualified Zener series designed for fail-safe voltage regulation in mission-critical systems where hermetic sealing, radiation hardness, and extreme temperature operation are mandatory.
FAQ
What is the Zener voltage tolerance for JANTX1N4978US/TR?
JANTX1N4978US/TR has a nominal Zener voltage of 68 V with a standard tolerance of ±5%, as defined in MIL-PRF-19500/356. This tolerance applies across the full operating temperature range (-65 °C to +175 °C) and ensures predictable regulation in high-reliability circuits without requiring post-manufacture trimming.
Does JANTX1N4978US/TR require heatsinking for 5 W operation?
JANTX1N4978US/TR is rated for 5 W dissipation at an end-cap temperature (TEC) of 140 °C, with a junction-to-end-cap thermal resistance of 7 °C/W. Effective heatsinking is achieved by soldering both end caps to large copper planes-no external heatsink is needed if PCB thermal design meets Microsemi's recommended pad layout and copper area guidelines.
Is JANTX1N4978US/TR compatible with lead-free reflow processes?
JANTX1N4978US/TR features copper end caps with Sn/Pb finish, making it incompatible with Pb-free reflow profiles. For RoHS-compliant assembly, Microsemi offers alternative qualified versions with matte tin terminations-consult the latest Microchip product change notice for Pb-free equivalents of JANTX1N4978US/TR.
How does the voidless-glass construction improve reliability of JANTX1N4978US/TR?
The voidless-glass construction of JANTX1N4978US/TR eliminates internal microvoids that could nucleate cracks or trap moisture under thermal cycling. Combined with triple-layer passivation and Category I metallurgical bonds, this structure prevents parameter drift and catastrophic failure in >100,000-cycle thermal stress tests per MIL-STD-883.
What is the maximum surge current rating for JANTX1N4978US/TR?
JANTX1N4978US/TR is rated for a non-repetitive peak surge current (IZSM) of 18.7 A at an 8.3 ms half-sine waveform. This rating is validated per MIL-PRF-19500/356 and ensures survivability during lightning-induced transients in avionics and radar power supplies.
JANTX1N4978CUS/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:
- ±2%
- 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
JANTX1N4978CUS/TR FAQ
1.How can I place an order for JANTX1N4978CUS/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for JANTX1N4978CUS/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 JANTX1N4978CUS/TR reliable?
The price and inventory of JANTX1N4978CUS/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for JANTX1N4978CUS/TR is usually 5 days.
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Once your JANTX1N4978CUS/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 JANTX1N4978CUS/TR?
For technical support, including JANTX1N4978CUS/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your JANTX1N4978CUS/TR requirements.
6.How does Aetrix verify that JANTX1N4978CUS/TR is sourced from the original manufacturer or authorized distributors?
All JANTX1N4978CUS/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 JANTX1N4978CUS/TR meets industry standards.
7.What is the process for return or replacement of JANTX1N4978CUS/TR?
All JANTX1N4978CUS/TR units undergo pre-shipment inspection (PSI). If there is an issue with JANTX1N4978CUS/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 JANTX1N4978CUS/TR part is unused and in its original packaging.
Return procedure for JANTX1N4978CUS/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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