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HomeProductsDiscrete Semiconductor ProductsDiodes - Zener - SingleJANTX1N4978C
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JANTX1N4978C - Microsemi Corporation

Manufacturer Part Number
JANTX1N4978C
Manufacturer
Microsemi
Allelco Part Number
98D-JANTX1N4978C
Warranty
1 Year Allelco Warranty - Find out more
Stock Status:
47,621 pcs available, New & Original
Parts Description
DIODE ZENER 68V 5W E AXIAL
Package
E, Axial
Data sheet
JANTX1N4978C.pdf
RoHs Status
 
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In stock: 47621
  • Unit Price: $18.255
  • Subtotal: $0.00

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Quantity Unit Price Ext. Price
1+ $18.255 $18.26
The above prices does not include taxes and freight rates, which will be calculated on the order pages.

Specifications

JANTX1N4978C Tech Specifications
Microsemi Corporation - JANTX1N4978C technical specifications, attributes, parameters and parts with similar specifications to Microsemi Corporation - JANTX1N4978C

Product Attribute Attribute Value
Manufacturer Microsemi
Voltage - Zener (Nom) (Vz) 68 V
Voltage - Forward (Vf) (Max) @ If 1.5 V @ 1 A
Tolerance ±2%
Supplier Device Package E, Axial
Series Military, MIL-PRF-19500/435
Power - Max 5 W
Product Attribute Attribute Value
Package / Case E, Axial
Package Bulk
Operating Temperature -65°C ~ 175°C
Mounting Type Through Hole
Impedance (Max) (Zzt) 50 Ohms
Current - Reverse Leakage @ Vr 2 µA @ 51.7 V
Base Product Number 1N4978

Environmental & Export Classifications

ATTRIBUTE DESCRIPTION
RoHs Status RoHS non-compliant
Moisture Sensitivity Level (MSL) 1 (Unlimited)
REACH Status REACH Unaffected
ECCN EAR99

Frequently Asked Questions(FAQ)

What are the key electrical characteristics and performance limits of the JANTX1N4978C Zener diode that influence its use in high-reliability power regulation circuits?
The JANTX1N4978C operates with a nominal Zener voltage of 68 V, tightly controlled within ±2% tolerance to ensure stable reference behavior across temperature extremes from -65°C to 175°C. With a maximum power dissipation of 5 W and a dynamic impedance (Zzt) of 50 Ohms at rated conditions, it provides precise voltage clamping suitable for precision regulation where load variations may occur. Its reverse leakage current remains below 2 µA at 51.7 V, minimizing standby losses in low-power supervisory applications. Forward voltage drop is limited to 1.5 V at 1 A, which affects switching efficiency in bidirectional protection scenarios.
How does the JANTX1N4978C compare to commercial-grade equivalents like the standard 1N4978C in terms of reliability, qualification standards, and suitability for defense or aerospace systems?
Unlike commercial versions, the JANTX1N4978C meets MIL-PRF-19500/435 qualification, indicating rigorous environmental and lifecycle testing including thermal cycling, radiation exposure, and extended burn-in. This makes it appropriate for mission-critical applications where failure rate must be minimized. While both share the same base part number and electrical parameters, only the JANTX variant guarantees consistent performance under extreme mechanical stress and wide operating temperatures, justifying its use in aerospace or military power management despite higher cost and RoHS non-compliance.
Can the JANTX1N4978C safely handle surge currents above 1 A without exceeding its thermal limits when used in transient voltage suppression roles?
Although the forward voltage drop rises to 1.5 V at 1 A, the device’s 5 W maximum power rating implies a strict limit on sustained current. In transient events, peak currents can exceed 1 A if duration is short enough to avoid junction overheating. However, due to its axial E-package and moderate thermal mass, uncontrolled surges may lead to localized heating unless supplemented with external snubbing or heat sinking. Designers should consult the derating curve in the full datasheet to assess safe operating area under real-world surge profiles.
Why would an engineer choose the through-hole E, Axial package of the JANTX1N4978C instead of modern surface-mount alternatives despite space constraints in compact systems?
The axial E package offers superior thermal resistance and mechanical robustness compared to many SMD Zeners, especially under vibration and thermal shock—critical factors in military or avionics environments. Its bulk packaging also supports high-volume assembly workflows common in legacy system retrofits. While not ideal for miniaturized designs, the reliability margin provided by this package often outweighs size concerns when long-term stability is paramount.
What impact do the ±2% tolerance and 50 Ohm impedance have on the output ripple voltage when the JANTX1N4978C is used as a shunt regulator with variable load currents?
At full rated power (5 W), a 50 Ohm dynamic impedance results in approximately 2.5 mV RMS ripple amplification per milliampere of load variation under steady-state conditions. Coupled with the tight ±2% initial accuracy, this ensures minimal voltage drift across the regulated bus, reducing the need for additional filtering in precision analog subsystems. However, designers must account for this impedance during worst-case analysis when loads transition abruptly near the knee point.
Is the JANTX1N4978C compatible with automated pick-and-place systems, and how does its MSL rating affect storage and handling requirements?
The JANTX1N4978C has an MSL rating of 1, meaning it is not sensitive to moisture and can be stored indefinitely without bake-out procedures. However, as a through-hole component in axial packaging, it is generally not processed via standard surface-mount lines; manual insertion or wave soldering setups are typically required. This limits automation benefits but aligns with legacy manufacturing infrastructure still prevalent in defense contracts.
Given its RoHS non-compliance, what regulatory challenges might arise when sourcing or deploying the JANTX1N4978C in civilian industrial equipment subject to international trade laws?
Because the JANTX1N4978C contains lead-based terminations or plating, it violates RoHS directives effective in the EU and other regions. Use in consumer or general industrial equipment may require exemption filings under Directive 2011/65/EU. For defense or aerospace projects where RoHS exemptions apply, this is less problematic. Engineers must verify end-use classification before deployment to avoid compliance penalties.
How should thermal design considerations differ when integrating the JANTX1N4978C into a PCB layout compared to standard 1N4978C diodes?
Despite identical electrical behavior, the JANTX version’s military-grade construction often implies tighter internal bonding and more robust metallization, improving thermal conductivity slightly. Nevertheless, both devices benefit from adequate copper pours and spacing to dissipate 5 W effectively. In high-ambient-temperature environments above 125°C, the JANTX’s extended upper limit to 175°C allows continued operation where commercial parts might fail prematurely.
What are the implications of selecting the JANTX1N4978C over a lower-voltage Zener for overvoltage protection in a 68 V-rated DC-DC converter feedback loop?
Using a 68 V Zener like the JANTX1N4978C ensures the feedback network remains functional until the input exceeds safe thresholds, preserving regulation integrity during transients. Choosing a lower-voltage Zener risks false triggering under normal operational spikes, while a higher one could allow damaging voltages to pass unchecked. The JANTX’s precision and ruggedness make it ideal for setting accurate trip points in fault-protected power supplies.
Does the JANTX1N4978C exhibit significant temperature coefficient variation across its specified range, and how does this affect stability in temperature-varying applications?
As a silicon Zener, the JANTX1N4978C exhibits a negative temperature coefficient below its knee voltage and positive above, peaking around room temperature. Over its full range (-65°C to 175°C), this coefficient is manageable due to the high breakdown voltage (typically >5 V), resulting in less than 50 ppm/°C drift. This predictable behavior simplifies compensation in analog reference chains where long-term stability is essential.
How does the base product number 1N4978 relate to the JANTX1N4978C, and why might engineers cross-reference between military and commercial variants during component substitution?
The 1N4978 is the commercial baseline from which the JANTX1N4978C is derived. While they share core parameters like 68 V Zener voltage and 5 W rating, only the JANTX variant includes full MIL-SPEC qualification and extended temperature assurance. Substituting without verifying qualification status can introduce unanticipated failure modes in critical systems, so engineers often use the base number as a lookup anchor while validating traceability and test data.
What role does the ECCN designation EAR99 play in procurement decisions involving the JANTX1N4978C, particularly for global supply chains?
Classified under EAR99, the JANTX1N4978C falls under U.S. export controls as a "not-controlled" commodity, simplifying international sourcing logistics. However, exporters must still comply with country-specific regulations regarding end-use, destination, and license exceptions. For most non-defense customers, this designation reduces administrative overhead compared to items requiring BIS licenses.
In what ways does the 5 W power rating constrain the allowable series resistance in a voltage divider configuration using the JANTX1N4978C?
When used as a shunt regulator, the total power dissipated includes both Zener loss and any series resistor power. Assuming worst-case input voltage, the series resistor must limit current such that I × Vz < 5 W. For example, at 75 V input, max current is ~109 mA, yielding a minimum series resistance of ~690 Ohms. Exceeding this risks thermal runaway unless heatsinking or current limiting is implemented.
Are there typical failure modes associated with the JANTX1N4978C that differentiate it from non-military Zeners under accelerated life testing conditions?
Under MIL standards, the JANTX1N4978C undergoes enhanced screening including HAST (Highly Accelerated Stress Test) and thermal shock. Common failure mechanisms like electromigration and bond wire degradation are mitigated through improved material selection and process control. However, abrupt overpowering or improper mounting (e.g., excessive solder flux residue) can still cause localized hotspots, underscoring the need for adherence to recommended layout guidelines.
How does the absence of a defined Moisture Sensitivity Level beyond MSL 1 affect storage practices for large quantities of JANTX1N4978C components?
With MSL 1, the JANTX1N4978C is considered non-moisture-sensitive and can remain in original packaging indefinitely without humidity conditioning. This simplifies warehousing and reduces handling costs in high-stock environments, particularly beneficial for defense contractors maintaining inventory for rapid field replacements or system upgrades under long warranty periods.
What considerations apply when cascading multiple Zener diodes, including the JANTX1N4978C, to achieve a composite breakdown voltage greater than 68 V?
Cascading introduces parasitic capacitance and potential interaction effects due to differing Zener knee behaviors. To maintain accuracy, matched devices like the JANTX1N4978C should be used with sufficient spacing or isolation resistors. Without proper buffering, the effective Zener voltage may deviate from the sum of individual ratings, especially under fast transient conditions.

Parts with Similar Specifications

The three parts on the right have similar specifications to Microsemi Corporation JANTX1N4978C

Product Attribute JANTX1N4978CUS/TR JANTX1N4978CUS JANTX1N4978DUS/TR JANTX1N4978D
Part Number JANTX1N4978CUS/TR JANTX1N4978CUS JANTX1N4978DUS/TR JANTX1N4978D
Manufacturer Microchip Technology Microsemi Corporation Microchip Technology Microsemi Corporation
Voltage - Zener (Nom) (Vz) - - - -
Mounting Type - Surface Mount Through Hole Surface Mount
Current - Reverse Leakage @ Vr - - - -
Supplier Device Package - 196-NFBGA (12x12) 16-PDIP 64-VQFN (9x9)
Package - Tape & Reel (TR) Tube Tape & Reel (TR)
Operating Temperature - -40°C ~ 85°C 0°C ~ 70°C -40°C ~ 85°C
Tolerance - - - -
Power - Max - - - -
Voltage - Forward (Vf) (Max) @ If - - - -
Impedance (Max) (Zzt) - - - -
Base Product Number - DAC34H84 MAX500 ADS62P42
Package / Case - 196-LFBGA 16-DIP (0.300', 7.62mm) 64-VFQFN Exposed Pad
Series - - - -

JANTX1N4978C Datasheet PDF

Download JANTX1N4978C pdf datasheets and Microsemi Corporation documentation for JANTX1N4978C - Microsemi Corporation.

Environmental Information
Microchip CA Prop65.pdf Microchip REACH.pdf Microchip RoHS.pdf

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Customer Reviews

Evaluation: 10 Articles

  • Dani***alkerTech
    Jun 1, 2026

    Product works, but setup took more effort than expected. Once configured the MCU ran reliably, although documentation support felt older compared with newer platforms. Fine for maintenance projects.

  • Yuki***aka88
    May 26, 2026

    信号通信プロジェクトでこのRS-485トランシーバーを使用しました。設置は簡単で、長距離ケーブルでも通信は安定していました。消費電力も、以前使用していたものより低くなっています。

  • Stev***aker
    May 20, 2026

    Solid diode for power rectification. Works well in switching circuits.

  • Bran***Lewis
    May 11, 2026

    Compact FPGA with good performance. Suitable for basic signal processing tasks.

  • Oliv***arris
    May 7, 2026

    Reliable I/O expander. Works well in embedded control applications.

  • Jess***Jones
    Apr 17, 2026

    It offers good value for the price, and the specifications match the description. I’ve been using it for two days with no issues, and I’ll definitely buy it again if I need it in the future.

  • Mich***Smith
    Apr 17, 2026

    Shipping was on time, the component pins are neatly aligned, and I tested 10 of them with a multimeter—all readings were within the specified range. Highly recommended.

  • Aman***arris
    Apr 3, 2026

    It was great—the entire process, from placing the order to receiving the package, went very smoothly. The components were consistent, the price was fair, and I had a very pleasant shopping experience.

  • Mike***nch
    Apr 3, 2026

    Better than expected! The resistance and capacitance readings were spot-on, and it passed the test on the first try. The service was reliable, and the packaging was thoughtful—I highly recommend it.

  • Daic***K.
    Mar 23, 2026

    Very good. No issue after long time testing.

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Region Country Logistic Time(Day)
America United States 5
Brazil 7
Europe Germany 5
United Kingdom 4
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Oceania Australia 6
New Zealand 5
Asia India 4
Japan 4
Middle East Israel 6
DHL & FedEx Shipment Charges Reference
Shipment charges(KG) Reference DHL(USD$)
0.00kg-1.00kg USD$30.00 - USD$60.00
1.00kg-2.00kg USD$40.00 - USD$80.00
2.00kg-3.00kg USD$50.00 - USD$100.00
Note:
The above table is for reference only. There may have some data bias for the uncontrollable factors.
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Microsemi Corporation

JANTX1N4978C

Microsemi Corporation
98D-JANTX1N4978C

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