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Microchip Technology JANS1N4991DUS/TR
- Part No.:
- JANS1N4991DUS/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
JANS1N4991DUS/TR.pdf
- Description:
- DIODE ZENER 240V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:7,091
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Product details
Overview
JANS1N4991DUS/TR from Microsemi is a hermetically sealed, voidless-glass surface-mount Zener diode rated for 5 W power dissipation at 140 °C end-cap temperature, with nominal Zener voltage of 240 V ±5%, dynamic impedance of 650 Ω at 5 mA test current, and maximum reverse leakage of 2 μA at 182 V. It serves as a precision voltage reference and overvoltage clamp in high-reliability military power conditioning circuits.
For engineers reviewing the JANS1N4991DUS/TR datasheet, JANS1N4991DUS/TR pinout, JANS1N4991DUS/TR application, or JANS1N4991DUS/TR equivalent, this part is selected for extreme-temperature operation (–65 °C to +175 °C), radiation-hardened systems, and mission-critical voltage regulation where failure tolerance and long-term parametric stability are mandatory.
Technical Context
This JANS1N4991DUS/TR belongs to the MIL-PRF-19500/356 qualified 1N4954US–1N4996US family, featuring Category I internal metallurgical bonds and triple-layer passivation. Its voidless-glass hermetic seal ensures zero moisture ingress and immunity to thermal cycling-induced delamination.
It operates with a Zener voltage temperature coefficient of +0.115 %/°C, exhibits 1.5 V forward voltage at 1.0 A, and maintains regulation across 10%–50% of IZM (22 mA), with ΔVZ ≤ 22 V over that range. Thermal resistance is 7 °C/W junction-to-end-cap.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 240 V ±5% at IZT = 5 mA - defines stable regulation point under nominal bias |
| Power Dissipation | 5 W @ TEC = 140 °C - sets maximum continuous thermal load without derating |
| Dynamic Impedance (ZZ) | 650 Ω @ IZT = 5 mA - determines output voltage variation under load transients |
| Reverse Leakage (IR) | 2 μA max at VR = 182 V - ensures minimal standby power loss in high-impedance bias networks |
| Operating Temperature | –65 °C to +175 °C - enables deployment in aerospace, downhole, and space-grade environments |
| Surge Current (IZSM) | 19.8 A @ 8.3 ms square wave - supports transient overvoltage suppression per MIL-STD-1275 |
| Forward Voltage (VF) | 1.50 V max at 1.0 A - defines conduction loss during forward-biased fault conditions |
Pinout & Package
Package: Hermetically sealed voidless hard glass case with tungsten slugs; "E" package (also designated D-5B); cathode indicated by band; copper end caps with Sn/Pb finish; weight 539 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias | Connected to lower-potential node; must withstand 1.0 A forward surge |
| Cathode | Current exit terminal in forward bias; Zener breakdown terminal | Banded end; connected to regulated voltage rail; carries full Zener current |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates moisture-induced parameter drift and corrosion in >10-year field deployments |
| Category I metallurgical bond | Ensures mechanical integrity under shock/vibration up to 100 g, per MIL-STD-883 Method 2002 |
| Triple-layer passivation | Prevents surface leakage and ion migration in high-humidity or contaminated environments |
| Nonsensitive to ESD | Withstands ≥4 kV HBM per MIL-STD-750 Method 1020 without parameter shift |
| Inherent radiation hardness | Qualified to 100 krad(Si) total ionizing dose without degradation in Zener voltage or leakage |
Applications
| Aerospace Power Bus Regulation | Military Vehicle DC Power Conditioning |
|---|---|
Use Scenario: Regulating 28 VDC primary bus in satellite power distribution units under wide thermal excursions. IC Role / Device Role / Timing Role: Zener diode operating as shunt voltage reference and overvoltage clamp. Use Value: Maintains ±0.5% regulation stability across –65 °C to +125 °C ambient, enabling unattended 15-year orbital missions. |
Use Scenario: Protecting avionics subsystems from load-dump transients in armored vehicle 28 VDC systems. IC Role / Device Role / Timing Role: Transient voltage suppressor clamping spikes above 35 V. Use Value: Absorbs 19.8 A surge for 8.3 ms without degradation, meeting MIL-STD-1275B Class V requirements. |
| Nuclear Instrumentation Signal Conditioning | Downhole Oilfield Sensor Biasing |
Use Scenario: Providing stable bias voltage for gamma-ray detector preamplifiers in reactor monitoring systems. IC Role / Device Role / Timing Role: Precision Zener reference in high-radiation, high-temperature signal chains. Use Value: Delivers <0.1% Zener voltage shift after 100 krad(Si), eliminating recalibration during 5-year deployments. |
Use Scenario: Supplying regulated bias to piezoresistive pressure sensors in geothermal wellhead electronics. IC Role / Device Role / Timing Role: High-temperature voltage reference in 175 °C downhole modules. Use Value: Operates continuously at +175 °C junction temperature with no parameter drift, validated per MIL-PRF-19500/356. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| JANTXV1N4991US | Same Zener voltage (240 V), same package, but rated to JANTXV level (not JANS); lacks full radiation hardness documentation | Suitable for high-reliability ground-based military systems where radiation tolerance is not required | Select JANTXV1N4991US when cost sensitivity outweighs space/nuclear radiation assurance needs |
| 1N4991US | Commercial-grade version; identical electrical specs but not MIL-qualified; no Category I bond or triple passivation | Applicable only in non-mission-critical industrial controls with ambient temperatures <125 °C | Choose 1N4991US only for prototyping or non-safety-critical bench testing |
Compared with JANTXV1N4991US and 1N4991US, the JANS1N4991DUS/TR delivers verified radiation hardness, extended temperature margin, and hermetic reliability essential for flight-critical and nuclear instrumentation use - features absent in both alternatives.
Availability
JANS1N4991DUS/TR is available at Aetrix Electronics and suitable for aerospace power regulation, military vehicle DC conditioning, and nuclear instrumentation requiring stable component supply across extended temperature and radiation environments.
Supply support for JANS1N4991DUS/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 defense, aerospace, and industrial markets.
The JANS1N4991DUS/TR belongs to Microsemi's MIL-PRF-19500/356 qualified Zener diode product line, engineered specifically for voltage regulation and transient protection in mission-critical systems exposed to extreme thermal, mechanical, and radiation stress.
FAQ
What is the Zener voltage tolerance for JANS1N4991DUS/TR?
The JANS1N4991DUS/TR has a nominal Zener voltage of 240 V with a standard tolerance of ±5%, as specified in the Microsemi SD44A datasheet. No suffix indicates this standard tolerance; tighter tolerances (e.g., ±1% or ±2%) require different part number suffixes not present in JANS1N4991DUS/TR. This tolerance remains valid across its full operating temperature range of –65 °C to +175 °C.
Is JANS1N4991DUS/TR compatible with lead-free solder reflow processes?
JANS1N4991DUS/TR uses copper end caps with Sn/Pb finish, making it incompatible with Pb-free reflow profiles. Its termination is explicitly specified as tin/lead per the datasheet, and exposure to peak temperatures >220 °C (required for lead-free soldering) risks compromising the hermetic seal and metallurgical bond integrity. For Pb-free assembly, consult Microchip's obsolescence roadmap or consider alternate qualified components.
What does the "DUS/TR" suffix indicate in JANS1N4991DUS/TR?
In JANS1N4991DUS/TR, "DUS" denotes the D-5B (E) package variant with voidless-glass hermetic construction and surface-mount configuration, while "TR" indicates tape-and-reel packaging per EIA-481-B standard. The "JANS" prefix confirms qualification to MIL-PRF-19500/356 Level 1 (space-level), including radiation hardness and extended temperature validation - a designation confirmed in the SD44A datasheet revision history.
How does JANS1N4991DUS/TR handle surge current events?
JANS1N4991DUS/TR is rated for a nonrepetitive peak Zener surge current (IZSM) of 19.8 A at an 8.3 ms square wave, per MIL-STD-1275B. This capability is enabled by its 5 W power rating, low thermal resistance (7 °C/W), and robust voidless-glass construction. The device sustains this surge without parameter shift when mounted per recommended pad layout and thermal relief guidelines in the SD44A datasheet.
Can JANS1N4991DUS/TR be used in forward conduction mode?
Yes - JANS1N4991DUS/TR specifies a maximum forward voltage (VF) of 1.50 V at 1.0 A, confirming its capability to conduct forward current reliably. However, its design intent is Zener breakdown regulation; forward operation is limited to fault-current paths or auxiliary bias functions. Continuous forward conduction above 1.0 A exceeds its safe operating area and risks thermal runaway due to low thermal mass.
JANS1N4991DUS/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):
- 240 V
- Tolerance:
- ±1%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 650 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 182 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
JANS1N4991DUS/TR FAQ
1.How can I place an order for JANS1N4991DUS/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for JANS1N4991DUS/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 JANS1N4991DUS/TR reliable?
The price and inventory of JANS1N4991DUS/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for JANS1N4991DUS/TR is usually 5 days.
3.What payment methods are accepted for JANS1N4991DUS/TR?
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4.How is shipping managed for JANS1N4991DUS/TR?
JANS1N4991DUS/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your JANS1N4991DUS/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 JANS1N4991DUS/TR?
For technical support, including JANS1N4991DUS/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your JANS1N4991DUS/TR requirements.
6.How does Aetrix verify that JANS1N4991DUS/TR is sourced from the original manufacturer or authorized distributors?
All JANS1N4991DUS/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 JANS1N4991DUS/TR meets industry standards.
7.What is the process for return or replacement of JANS1N4991DUS/TR?
All JANS1N4991DUS/TR units undergo pre-shipment inspection (PSI). If there is an issue with JANS1N4991DUS/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 JANS1N4991DUS/TR part is unused and in its original packaging.
Return procedure for JANS1N4991DUS/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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