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Microchip Technology 1N4995US/TR
- Part No.:
- 1N4995US/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
1N4995US/TR.pdf
- Description:
- DIODE ZENER 360V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:93
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Product details
Overview
1N4995US/TR from Microsemi is a surface-mount, voidless hermetically sealed glass Zener diode rated for 5 W power dissipation at 140 °C end-cap temperature, with nominal Zener voltage of 360 V ±5%, dynamic impedance of 1400 Ω at 3 mA test current, and maximum reverse leakage current of 2 μA at 274 V. It serves as a precision voltage reference and overvoltage clamp in high-reliability aerospace power conditioning circuits.
For engineers reviewing the 1N4995US/TR datasheet, 1N4995US/TR pinout, 1N4995US/TR application, or 1N4995US/TR equivalent, this part is selected for mission-critical voltage regulation where extended temperature operation (–65 °C to +175 °C), radiation hardness, and ESD immunity per MIL-STD-750 Method 1020 are mandatory design requirements.
Technical Context
This device belongs to the MIL-PRF-19500/356 qualified 1N4954US–1N4996US series, featuring triple-layer passivation and Category I internal metallurgical bonds. Its voidless-glass construction ensures hermetic sealing without internal cavities, directly supporting long-term reliability under thermal cycling and humidity exposure.
The 1N4995US/TR operates across –65 °C to +175 °C junction temperature range with thermal resistance of 7 °C/W (junction-to-end-cap) and surge capability of 35 A (8.3 ms square wave). It exhibits a positive temperature coefficient of +0.120 %/°C at 3 mA, enabling predictable drift behavior in wide-temperature designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 360 V ±5% at 3 mA - defines stable regulation point for high-voltage biasing and clamping |
| Power Dissipation | 5 W @ TEC = 140 °C - sets maximum continuous thermal load under conduction-cooled mounting |
| Dynamic Impedance (ZZ) | 1400 Ω @ IZT = 3 mA - determines output voltage stability under varying load current |
| Reverse Leakage (IR) | 2 μA @ VR = 274 V - ensures minimal parasitic current in high-impedance sensing paths |
| Surge Current (IZSM) | 35 A @ 8.3 ms - supports transient overvoltage suppression without failure |
| Temp. Coefficient (αVZ) | +0.120 %/°C @ IZT = 3 mA - enables accurate drift compensation in precision references |
| Forward Voltage (VF) | 1.50 V @ 1.0 A - defines conduction loss during forward-biased fault conditions |
Pinout & Package
Package: Hermetically sealed voidless hard glass case with tungsten slugs; end caps are copper with Sn/Pb finish; polarity indicated by cathode band; weight 539 mg; tape-and-reel compliant with EIA-481-B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node in reverse-biased Zener configuration; carries full surge current during clamping |
| Cathode | Zener breakdown terminal | Marked with band; connected to regulated voltage rail; referenced for voltage stabilization and overvoltage protection |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates internal moisture ingress and delamination risk over 20+ year field life in space-grade environments |
| Category I metallurgical bond | Ensures mechanical integrity and thermal continuity between die and slug under shock/vibration up to 100 g |
| Triple-layer passivation | Prevents surface conduction paths and leakage growth under high-humidity, high-bias stress conditions |
| MIL-PRF-19500/356 qualification | Validates performance compliance for JAN, JANTX, JANTXV, and JANS screening levels required in defense systems |
| Radiation hardness | Inherently tolerant to total ionizing dose (TID) per MicroNote 050 - no derating needed up to 100 krad(Si) |
Applications
| Aerospace Power Bus Protection | High-Voltage Instrumentation Reference |
|---|---|
Use Scenario: Clamp transients on 28 V and 115 V AC/DC distribution buses in satellite power management units. IC Role / Device Role / Timing Role: Zener diode operating in reverse breakdown to limit bus overvoltage to safe thresholds. Use Value: Withstands 35 A surge (8.3 ms) and maintains regulation within ±5% across –65 °C to +175 °C, ensuring fault containment without replacement. |
Use Scenario: Provide stable 360 V reference for calibration of high-voltage test equipment and electron beam supplies. IC Role / Device Role / Timing Role: Precision voltage reference element in feedback loops of programmable HV DC sources. Use Value: Low 2 μA leakage at 274 V and +0.120 %/°C tempco enable sub-0.1% absolute accuracy over military temperature range. |
| Nuclear Instrumentation Signal Conditioning | Tactical Radar Bias Supply Stabilization |
Use Scenario: Regulate detector bias voltage in radiation-hardened neutron/gamma spectrometers deployed in reactor monitoring systems. IC Role / Device Role / Timing Role: High-reliability Zener shunt regulator maintaining constant detector bias despite supply ripple and temperature swings. Use Value: Voidless-glass construction and Category I bond prevent parametric shift after 100 krad(Si) exposure, preserving measurement fidelity. |
Use Scenario: Stabilize collector supply rails for GaN RF power amplifiers in airborne radar front-ends operating at elevated ambient temperatures. IC Role / Device Role / Timing Role: Voltage clamp protecting amplifier stages from switching-induced overshoot during pulse modulation. Use Value: 5 W power rating at 140 °C end-cap temperature allows direct mounting to heat-spreading chassis without heatsink, reducing SWaP-C. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4995US | Same electrical specs and package; differs only in packaging format (bulk vs. tape-and-reel) | No functional difference; identical use in PCB assembly and qualification testing | Select 1N4995US/TR when automated pick-and-place requires EIA-481-B compliant tape-and-reel delivery |
| 1N4995 | Axial-leaded variant (no "US" suffix); same Zener voltage, tolerance, and power rating but different thermal path and mounting method | Requires through-hole PCB layout and wave solder process; not suitable for SMT-only lines | Choose 1N4995 only if legacy board design mandates axial leads or manual prototyping is preferred |
Compared with 1N4995US and 1N4995, the 1N4995US/TR offers identical Zener performance and MIL-qualified reliability while enabling high-volume SMT production via standardized tape-and-reel handling-critical for aerospace OEMs requiring traceable, repeatable assembly.
Availability
1N4995US/TR is available at Aetrix Electronics and suitable for aerospace power bus protection, high-voltage instrumentation reference, nuclear instrumentation signal conditioning, and tactical radar bias supply stabilization requiring stable component supply across extended temperature and radiation environments.
Supply support for 1N4995US/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.
The 1N4995US/TR belongs to Microsemi's MIL-PRF-19500/356-qualified Zener diode product line, engineered specifically for voltage regulation and overvoltage protection in mission-critical systems where failure is not an option.
FAQ
What is the Zener voltage tolerance for 1N4995US/TR?
The 1N4995US/TR has a nominal Zener voltage of 360 V with a standard tolerance of ±5%, as specified in the Microsemi SD44A datasheet. No suffix indicates this standard tolerance; tighter tolerances (e.g., ±2% or ±1%) require C or D suffixes not present in this part number. This tolerance applies at 25 °C and under specified test conditions (IZT = 3 mA).
Does 1N4995US/TR meet military specifications?
Yes, the 1N4995US/TR is qualified to MIL-PRF-19500/356 and supports JAN, JANTX, JANTXV, and JANS screening levels. It features Category I internal metallurgical bonds, triple-layer passivation, and voidless hermetic glass construction-all verified per military test methods including MIL-STD-750 for ESD immunity.
What is the maximum operating temperature for 1N4995US/TR?
The 1N4995US/TR supports continuous operation from –65 °C to +175 °C junction temperature. Its 5 W power rating is specified at 140 °C end-cap temperature, with linear derating to zero at +175 °C. This wide range enables deployment in engine-mounted avionics and downhole oilfield electronics.
How does the thermal resistance of 1N4995US/TR affect PCB layout?
The 1N4995US/TR has a junction-to-end-cap thermal resistance of 7 °C/W. To maintain reliability, the PCB must provide low-thermal-resistance paths-typically via large copper pads, thermal vias, and direct connection to chassis ground-to keep the end-cap temperature ≤140 °C at full 5 W dissipation.
Is 1N4995US/TR radiation hardened?
Yes, the 1N4995US/TR is inherently radiation hard per Microsemi MicroNote 050, exhibiting no parametric degradation up to 100 krad(Si) total ionizing dose. Its voidless-glass package and Category I metallurgical bond contribute to this hardness, making it suitable for satellite and nuclear instrumentation applications.
1N4995US/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):
- 360 V
- Tolerance:
- ±5%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 1400 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 274 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 1 A
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- E-MELF
1N4995US/TR FAQ
1.How can I place an order for 1N4995US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4995US/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 1N4995US/TR reliable?
The price and inventory of 1N4995US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4995US/TR is usually 5 days.
3.What payment methods are accepted for 1N4995US/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4995US/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4995US/TR?
1N4995US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4995US/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 1N4995US/TR?
For technical support, including 1N4995US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4995US/TR requirements.
6.How does Aetrix verify that 1N4995US/TR is sourced from the original manufacturer or authorized distributors?
All 1N4995US/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 1N4995US/TR meets industry standards.
7.What is the process for return or replacement of 1N4995US/TR?
All 1N4995US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4995US/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 1N4995US/TR part is unused and in its original packaging.
Return procedure for 1N4995US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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