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Home Products Discrete Semiconductor Products Diodes - Zener - Single~~JANTX1N4978DUS/TR~~

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JANTX1N4978DUS/TR - Microchip Technology

Name: Microchip Technology JANTX1N4978DUS/TR
Brand: Microchip Technology
SKU: JANTX1N4978DUS/TR
Price: 30.9 USD
Availability: InStock
Rating: 5 (5 reviews)

Manufacturer Part Number: JANTX1N4978DUS/TR

Manufacturer: Microchip Technology

Allelco Part Number: 98D-JANTX1N4978DUS/TR

Warranty: 1 Year Allelco Warranty - Find out more

Stock Status:: 42,274 pcs available, New & Original

Parts Description: VOLTAGE REGULATOR

Package: E-MELF

Data sheet: -

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Specifications

JANTX1N4978DUS/TR Tech Specifications
Microchip Technology - JANTX1N4978DUS/TR technical specifications, attributes, parameters and parts with similar specifications to Microchip Technology - JANTX1N4978DUS/TR

Product Attribute	Attribute Value
Manufacturer	Microchip Technology
Voltage - Zener (Nom) (Vz)	68 V
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 1 A
Tolerance	±1%
Supplier Device Package	E-MELF
Series	MIL-PRF-19500/356
Power - Max	5 W

Product Attribute	Attribute Value
Package / Case	SQ-MELF, E
Package	Tape & Reel (TR)
Operating Temperature	-65°C ~ 175°C (TJ)
Mounting Type	Surface Mount
Impedance (Max) (Zzt)	50 Ohms
Current - Reverse Leakage @ Vr	2 µA @ 51.7 V

Environmental & Export Classifications

ATTRIBUTE	DESCRIPTION
ECCN	EAR99

Frequently Asked Questions(FAQ)

What is the maximum operating temperature range for the JANTX1N4978DUS/TR zener diode, and how does this affect reliability in high-temperature industrial environments?: The JANTX1N4978DUS/TR is rated for an operating junction temperature range from -65°C to 175°C (TJ), which aligns with its military-grade qualification under MIL-PRF-19500/356. This wide thermal envelope enables deployment in harsh environments where transient thermal stress or sustained high temperatures are expected, such as power supply regulation modules or aerospace electronics. The ability to operate at 175°C ensures stable breakdown voltage performance without significant drift, making it suitable for applications where standard commercial components would fail due to thermal degradation.

How does the ±1% tolerance of the JANTX1N4978DUS/TR compare to typical commercial zener diodes, and what design implications does this precision have in high-accuracy voltage reference circuits?: The JANTX1N4978DUS/TR offers a tight voltage tolerance of ±1%, significantly narrower than most commercial-grade zeners that typically exhibit ±5% or wider variation. In precision analog systems requiring stable 68 V references, such as test equipment or instrumentation amplifiers, this level of accuracy reduces calibration overhead and improves measurement consistency. When cascading multiple regulators or using zeners in feedback networks, the tighter tolerance minimizes cumulative error propagation, enabling designs that meet stringent system-level accuracy budgets without additional trimming or compensation circuitry.

Can the JANTX1N4978DUS/TR be used in automotive applications, and how does its qualification profile support functional safety requirements compared to non-military components?: While not specifically qualified to AEC-Q101, the JANTX1N4978DUS/TR’s military-grade qualification under MIL-PRF-19500/356 implies rigorous screening for parametric stability, life testing, and environmental endurance far exceeding standard industrial parts. This makes it suitable for mission-critical automotive subsystems where reliability under thermal cycling and vibration is essential—such as battery management units or high-side protection circuits. However, customers seeking formal automotive compliance should verify with Microchip whether supplemental AEC validation exists, as military-grade devices can sometimes substitute for automotive use under strict engineering justification.

What is the reverse leakage current specification of the JANTX1N4978DUS/TR at 51.7 V, and how might this impact power efficiency in low-current reference applications?: At 51.7 V reverse bias, the JANTX1N4978DUS/TR exhibits a leakage current of no more than 2 µA. This low leakage ensures minimal quiescent power dissipation in standby or bias circuits where even microampere-level losses could accumulate across many units in distributed systems. For example, in a network of remote sensors powered by solar cells or long-life batteries, this characteristic helps preserve energy reserves during inactive periods. Compared to higher-leakage commercial zeners, this attribute supports longer operational lifetimes in energy-constrained deployments.

How does the dynamic impedance (Zzt) of 50 ohms in the JANTX1N4978DUS/TR influence transient response when regulating pulsed loads?: With a maximum dynamic impedance of 50 ohms, the JANTX1N4978DUS/TR introduces a finite droop in output voltage under rapid current transients. During load steps where the load current changes abruptly—such as in switching power supplies driving capacitive loads—the output can sag by approximately ΔV = Zzt × ΔI. For instance, a 100 mA transient would induce up to 5 mV of deviation at 68 V nominal. While acceptable in many analog regulation contexts, designers must consider this effect when interfacing with sensitive analog-to-digital converters or requiring sub-millivolt ripple performance.

Is the JANTX1N4978DUS/TR compatible with automated pick-and-place assembly processes, and what packaging features ensure reliable surface mount soldering?: Yes, the JANTX1N4978DUS/TR is delivered in Tape & Reel (TR) format, facilitating high-speed automated placement by PCB assembly equipment. Its E-MELF package features symmetrical leads optimized for vacuum pickup and precise alignment on standard MELF footprints. The absence of lead bending or fragile structures enhances handling robustness during reflow cycles. Given its military-grade construction, the component also demonstrates consistent solder joint integrity under thermal stress, reducing defect rates in mass production of defense or aerospace PCBs.

How does the power rating of 5 W for the JANTX1N4978DUS/TR translate into practical current capability under continuous operation?: Operating at 68 V Zener voltage with a maximum power dissipation of 5 W yields a theoretical maximum current of approximately 73.5 mA (P = V × I). However, real-world operation requires derating based on ambient temperature and heatsinking. In free-air conditions without forced cooling, the actual usable current may drop to 50–60 mA due to self-heating effects. Designers should consult Microchip’s application notes for thermal derating curves to ensure junction temperature remains below 175°C under worst-case conditions, especially in compact enclosures with limited airflow.

What ECCN classification applies to the JANTX1N4978DUS/TR, and what export control considerations should engineers evaluate before sourcing?: The JANTX1N4978DUS/TR carries an ECCN (Export Control Classification Number) of EAR99, indicating it is subject to U.S. export regulations but generally unrestricted for most civilian end-uses. Nevertheless, engineers must still comply with national trade laws—especially when integrating the device into products destined for embargoed regions. While the part itself may not require special licenses, downstream assemblies incorporating this zener could trigger controls if they fall under categories like 3A001 or 5A002. Proactive compliance review is advisable prior to global distribution.

How does the JANTX1N4978DUS/TR perform in terms of surge handling compared to lower-power zener alternatives?: The 5 W power rating and robust construction of the JANTX1N4978DUS/TR enable it to absorb higher-energy transient pulses than typical 1–2 W zeners. For instance, it can survive brief overvoltage events common in telecom lines or motor-driven systems without degradation. In contrast, smaller zeners may fail catastrophically during inductive kickback or lightning-induced surges. When protecting high-impedance nodes or critical ICs, pairing this zener with series resistors allows safe energy absorption while maintaining fast clamping response—a key advantage in ruggedized or field-deployable electronics.

What mounting configuration options exist for the JANTX1N4978DUS/TR, and how do thermal characteristics vary between surface mount and through-hole implementations?: The JANTX1N4978DUS/TR is designed exclusively for surface mount via the E-MELF package, eliminating through-hole compatibility. Surface mounting offers superior thermal conduction to the PCB plane, improving heat sinking and allowing closer proximity to other components. However, without dedicated heatsinks or metal-core substrates, thermal resistance remains relatively high (~150°C/W typical). Engineers should allocate sufficient copper area around the pad and avoid routing sensitive traces underneath to prevent coupling noise during high-current transients.

How does the forward voltage drop (Vf) of 1.5 V at 1 A relate to fault conditions or accidental forward biasing of the JANTX1N4978DUS/TR?: The specified forward voltage of 1.5 V at 1 A indicates that if the diode is accidentally forward-biased beyond its intended reverse role—such as during power-up sequencing errors or polarity reversal—it will conduct significantly and clamp voltage at ~1.5 V. This behavior can protect downstream circuitry from overvoltage but may also cause unintended power loss or heating if sustained. Designers should include series fuses or current-limiting resistors in high-reliability systems to prevent damage during such fault scenarios, leveraging the device’s inherent short-circuit resilience only within its 5 W rating.

What level of humidity resistance does the JANTX1N4978DUS/TR offer, given its military qualification, and how does this benefit long-term storage in tropical climates?: Although explicit humidity specifications aren’t listed, MIL-PRF-19500/356 includes environmental stress testing such as moisture resistance, which typically exceeds 85°C/85% RH for 1,000 hours. This ensures the JANTX1N4978DUS/TR maintains electrical parameters after exposure to high-humidity conditions. In tropical or maritime environments, this prevents corrosion-induced failures in PCB pads or solder joints, supporting shelf life extensions for stockpiled inventory or field repair kits where environmental extremes challenge conventional components.

How does the absence of RoHS exemption documentation affect the JANTX1N4978DUS/TR in regulated consumer electronics despite its military origin?: Military parts like the JANTX1N4978DUS/TR are often exempt from full RoHS compliance due to strategic or reliability reasons, but their sale into consumer markets requires careful evaluation. If imported into jurisdictions with strict enforcement (e.g., EU), distributors may refuse shipments unless proper documentation confirms lead content is below threshold limits. Engineers considering use in consumer devices should verify current regulatory status with suppliers, as misuse could result in product recalls or import bans, undermining both safety and brand reputation.

Can the JANTX1N4978DUS/TR be paralleled to increase current capacity, and what precautions are necessary to maintain balance across multiple units?: Paralleling multiple JANTX1N4978DUS/TR devices can extend current delivery but demands careful layout and matching. Due to the ±1% Vz tolerance, slight mismatches can cause unequal current sharing, leading to premature failure in one device. To mitigate this, each unit should have identical trace lengths, minimal parasitic inductance, and possibly individual ballast resistors (e.g., 1–10 Ω) in series. Thermal coupling via shared heatsinking further improves current balancing. This approach is viable only if total power stays within aggregate ratings and transient response requirements allow for slightly slower regulation dynamics.

How does the HTSUS code (8541.10.0050) influence customs valuation and duty calculations when importing the JANTX1N4978DUS/TR internationally?: Classified under Harmonized Tariff Schedule of the United States (HTSUS) code 8541.10.0050, the JANTX1N4978DUS/TR falls under semiconductor devices, including zener diodes. This code typically carries moderate tariff rates depending on bilateral trade agreements. Importers must declare accurate quantities and values to avoid penalties. Misclassification as a general resistor or passive component could trigger audits or fines. Engineers involved in procurement should work closely with logistics teams to ensure correct HS coding, particularly when consolidating military-spec parts into broader BOMs for international production.

What diagnostic or monitoring capabilities can be inferred from the leakage current parameter of the JANTX1N4978DUS/TR in aging systems?: The low reverse leakage current (≤2 µA at 51.7 V) provides a baseline for detecting early-stage degradation in fielded systems. Over time, junction defects or oxide layer breakdown can increase leakage exponentially. By periodically measuring leakage in redundant reference circuits, operators can infer impending failure before catastrophic outages occur. This principle is leveraged in satellite or avionics platforms where periodic health checks monitor semiconductor condition, extending mission assurance through predictive maintenance rather than scheduled replacement.

How does the surface-mount nature of the JANTX1N4978DUS/TR impact EMC performance in high-frequency digital systems?: Surface mounting reduces lead length, minimizing loop area and associated parasitic inductance compared to through-hole variants. For the JANTX1N4978DUS/TR used in snubber or TVS roles near switching nodes, this improves high-frequency clamping effectiveness and reduces radiated emissions. However, improper grounding or placement near noisy traces can couple interference into the zener’s cathode node, affecting regulation stability. Optimal layout involves placing the device close to protected loads with star-ground connections and avoiding parallel routing with clock or data lines to maintain signal integrity.

What role does the E-MELF package play in vibration resistance for aerospace applications using the JANTX1N4978DUS/TR?: The E-MELF package’s solid metal-cased construction provides mechanical rigidity against shock and vibration, critical in aerospace payloads or launch vehicles. Unlike plastic-encapsulated SMD parts susceptible to delamination, the JANTX1N4978DUS/TR’s hermetic-like structure resists fatigue cracking under cyclic stress. Combined with its military qualification, this ensures reliable operation throughout satellite lifecycles or missile guidance systems where component survival directly correlates to mission success.

Parts with Similar Specifications

The three parts on the right have similar specifications to Microchip Technology JANTX1N4978DUS/TR

Product Attribute
Part Number	JANTX1N4978CUS/TR	JANTX1N4977DUS/TR	JANTX1N4978US/TR	JANTX1N4979CUS/TR
Manufacturer	Microchip Technology	Microchip Technology	Microchip Technology	Microchip Technology
Power - Max	-	-	-	-
Impedance (Max) (Zzt)	-	-	-	-
Operating Temperature	-	-40°C ~ 85°C	0°C ~ 70°C	-40°C ~ 85°C
Package	-	Tape & Reel (TR)	Tube	Tape & Reel (TR)
Package / Case	-	196-LFBGA	16-DIP (0.300', 7.62mm)	64-VFQFN Exposed Pad
Voltage - Forward (Vf) (Max) @ If	-	-	-	-
Current - Reverse Leakage @ Vr	-	-	-	-
Tolerance	-	-	-	-
Voltage - Zener (Nom) (Vz)	-	-	-	-
Mounting Type	-	Surface Mount	Through Hole	Surface Mount
Supplier Device Package	-	196-NFBGA (12x12)	16-PDIP	64-VQFN (9x9)
Series	-	-	-	-

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