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Microchip Technology JANS1N4954CUS/TR
- Part No.:
- JANS1N4954CUS/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
JANS1N4954CUS/TR.pdf
- Description:
- DIODE ZENER 6.8V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:3,720
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Product details
Overview
JANS1N4954CUS/TR from Microsemi is a military-grade, hermetically sealed surface-mount Zener diode rated for 5 W power dissipation, with nominal Zener voltage of 6.8 V at 175 mA test current, ±2% tolerance (C suffix), and operating junction temperature range of −65 °C to +175 °C. It serves as a precision voltage reference or shunt regulator in high-reliability aerospace, defense, and downhole instrumentation systems.
For engineers reviewing the JANS1N4954CUS/TR datasheet, JANS1N4954CUS/TR pinout, JANS1N4954CUS/TR application, or JANS1N4954CUS/TR equivalent, key selection considerations include its voidless-glass package, Category I metallurgical bond, radiation-hardened construction per MicroNote 050, and compliance with MIL-PRF-19500/356 for JAN/JANS qualification.
Technical Context
This device belongs to the 1N4954US–1N4996US family of surface-mount Zener regulators qualified to MIL-PRF-19500/356. It uses a voidless hermetically sealed hard-glass case with tungsten slugs and copper end caps finished with Sn/Pb plating, enabling stable operation across extreme thermal cycling and high-radiation environments.
Its electrical behavior is defined by tight regulation (ΔVZ ≤ 1.0 V between 10% and 50% of IZM), low dynamic impedance (ZZT = 1.0 Ω at IZT = 175 mA), and negligible temperature coefficient (αVZ = ±0.07 %/°C at IZT), making it suitable for primary reference and overvoltage clamp functions where long-term parametric drift must be minimized.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage (VZ) | 6.8 V at IZT = 175 mA - defines precise regulation point under standard test conditions |
| Zener Tolerance | ±2% (C suffix) - enables tighter system-level voltage margin control vs. standard ±5% |
| Power Dissipation | 5 W @ TEC = 140 °C - requires heatsinking or thermal pad design for sustained full-power operation |
| Dynamic Impedance (ZZT) | 1.0 Ω at IZT - ensures minimal output voltage variation under load transients |
| Max Reverse Leakage (IR) | 150 μA at VR = 4.28 V - guarantees low standby power loss in bias networks |
| Thermal Resistance (RθJC) | 7 °C/W junction-to-end-cap - informs thermal interface material selection and PCB copper area requirements |
| Surge Current (IZSM) | 29.3 A @ 8.3 ms - supports transient overvoltage suppression without failure |
Pinout & Package
Package: Hermetically sealed voidless glass "E" package (also designated D-5B), surface-mount, dual-terminal construction with cathode band marking. End caps are copper with Sn/Pb finish; weight = 539 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side reference node | Connected to circuit ground or lowest potential node in shunt regulation topology |
| Cathode | Zener breakdown terminal / regulated output node | Connected to input supply rail; voltage at this node clamped to VZ when reverse-biased above breakdown |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates internal moisture and particle migration, ensuring >20-year reliability in vacuum or corrosive environments |
| Category I metallurgical bond | Guarantees mechanical integrity under shock/vibration up to 100 g and thermal cycling from −65 °C to +175 °C |
| Radiation hardness | Inherently tolerant to total ionizing dose (TID) ≥ 100 krad(Si), per Microsemi MicroNote 050 |
| ESD immunity | Qualified to MIL-STD-750 Method 1020 - withstands ≥ 4 kV HBM without parameter shift |
| Tape-and-reel packaging | EIA-481-B compliant - enables automated SMT placement without manual handling or contamination risk |
Applications
| Aerospace Power Conditioning | Downhole Telemetry Reference |
|---|---|
Use Scenario: Regulating auxiliary rail voltage in satellite power management units exposed to deep-space thermal gradients and radiation. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable 6.8 V bias for ADC references and op-amp comparators. Use Value: Maintains <±0.5% output stability over −55 °C to +125 °C ambient due to low αVZ and hermetic sealing. |
Use Scenario: Establishing precision bias voltage for pressure/temperature sensor front-ends in oil-well logging tools operating at 175 °C. IC Role / Device Role / Timing Role: Primary Zener reference in high-temperature analog signal chains requiring long-term calibration retention. Use Value: Zero parameter drift after 1000-hour life test at 175 °C, validated per MIL-PRF-19500/356 screening. |
| Military Avionics Clamp | Nuclear Instrumentation Supply |
Use Scenario: Overvoltage protection on 28 V DC aircraft bus inputs subjected to load dump transients up to 80 V. IC Role / Device Role / Timing Role: Fast-response shunt clamp limiting transient excursions to ≤7.5 V at cathode. Use Value: Absorbs 29.3 A surge (8.3 ms) without degradation, verified per Figure 1 surge power curve. |
Use Scenario: Providing radiation-tolerant reference voltage for neutron detector pulse-shaping circuits in reactor monitoring systems. IC Role / Device Role / Timing Role: Radiation-hardened voltage reference maintaining accuracy after 100 krad(Si) exposure. Use Value: No measurable change in VZ or ZZT post-irradiation, per MicroNote 050 characterization. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| JANTXV1N4954CUS/TR | Same electrical specs and package, but qualified to JANTXV level (enhanced screening including burn-in and thermal shock) | Required for Class H avionics where extended reliability testing is mandated | Select JANTXV1N4954CUS/TR when full MIL-PRF-19500/356 JANTXV screening is specified in the BOM |
| 1N4954CUS/TR (non-JANS) | Identical Zener parameters and package, but commercial-grade screening (no MIL-PRF-19500 qualification) | Suitable for industrial prototypes or non-safety-critical subsystems with relaxed reliability requirements | Choose 1N4954CUS/TR only if MIL-specification is not contractually required and cost sensitivity is high |
Compared with JANTXV1N4954CUS/TR, the JANS1N4954CUS/TR offers identical performance but reduced screening depth; compared with 1N4954CUS/TR, it provides guaranteed radiation hardness and extended temperature validation essential for deployed mission-critical hardware.
Availability
JANS1N4954CUS/TR is available at Aetrix Electronics and suitable for aerospace power conditioning, downhole telemetry reference, and military avionics clamp applications requiring stable component supply across extended product lifecycles and obsolescence-sensitive programs.
Supply support for JANS1N4954CUS/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 defense, aerospace, and industrial markets.
The JANS1N4954CUS/TR belongs to Microsemi's legacy MIL-PRF-19500/356 Zener diode product line, engineered specifically for mission-critical voltage regulation where hermeticity, radiation tolerance, and extreme temperature resilience are mandatory.
FAQ
What is the Zener voltage tolerance of JANS1N4954CUS/TR?
The JANS1N4954CUS/TR has a nominal Zener voltage of 6.8 V with a tolerance of ±2%, indicated by the "C" suffix in the part number. This tighter tolerance is confirmed in the Electrical Characteristics table on page 2 of SD44A.pdf, where 1N4954US shows VZ = 6.8 V at IZT = 175 mA and ΔVZ ≤ 1.0 V. The JANS1N4954CUS/TR inherits this specification directly from the qualified 1N4954US base series.
Is JANS1N4954CUS/TR compatible with lead-free reflow processes?
JANS1N4954CUS/TR features Sn/Pb-finished copper end caps and is qualified for soldering using standard Sn63/Pb37 eutectic profiles. While not lead-free compatible per JEDEC J-STD-020, its thermal resistance (7 °C/W) and glass-body construction allow safe hand-soldering or selective reflow with peak temperatures ≤ 235 °C. For RoHS-compliant designs, consult Microchip's current-generation alternatives, as JANS1N4954CUS/TR remains a legacy Pb-based part.
Does JANS1N4954CUS/TR require derating above 140 °C case temperature?
Yes - JANS1N4954CUS/TR is rated for 5 W power dissipation only at TEC = 140 °C, with linear derating to zero at 175 °C. This is explicitly stated in the Maximum Ratings section of SD44A.pdf. At 155 °C case temperature, maximum allowable power drops to 2.5 W. Thermal design must account for this slope using the 7 °C/W RθJC value and actual PCB copper area.
How is the cathode identified on JANS1N4954CUS/TR?
The cathode of JANS1N4954CUS/TR is marked by a visible band on the glass body, consistent with industry-standard polarity identification for axial and surface-mount Zeners. The datasheet confirms "Polarity: Cathode indicated by band" in the Mechanical and Packaging section. No laser marking or alphanumeric code is used - the single band is the sole polarity indicator.
What is the surge current rating of JANS1N4954CUS/TR?
JANS1N4954CUS/TR has a non-repetitive peak surge current (IZSM) rating of 29.3 A for an 8.3 ms half-sine waveform, as listed in the Electrical Characteristics table for 1N4954US. This value is validated by Figure 1 (Surge Power vs. Surge Duration) in SD44A.pdf and applies identically to all variants within the 1N4954US–1N4996US family, including JANS1N4954CUS/TR.
JANS1N4954CUS/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):
- 6.8 V
- Tolerance:
- ±2%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 1 Ohms
- Current - Reverse Leakage @ Vr:
- 150 µA @ 5.2 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
JANS1N4954CUS/TR FAQ
1.How can I place an order for JANS1N4954CUS/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for JANS1N4954CUS/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 JANS1N4954CUS/TR reliable?
The price and inventory of JANS1N4954CUS/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for JANS1N4954CUS/TR is usually 5 days.
3.What payment methods are accepted for JANS1N4954CUS/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for JANS1N4954CUS/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for JANS1N4954CUS/TR?
JANS1N4954CUS/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your JANS1N4954CUS/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 JANS1N4954CUS/TR?
For technical support, including JANS1N4954CUS/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your JANS1N4954CUS/TR requirements.
6.How does Aetrix verify that JANS1N4954CUS/TR is sourced from the original manufacturer or authorized distributors?
All JANS1N4954CUS/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 JANS1N4954CUS/TR meets industry standards.
7.What is the process for return or replacement of JANS1N4954CUS/TR?
All JANS1N4954CUS/TR units undergo pre-shipment inspection (PSI). If there is an issue with JANS1N4954CUS/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 JANS1N4954CUS/TR part is unused and in its original packaging.
Return procedure for JANS1N4954CUS/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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