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Microchip Technology 1N4495US/TR
- Part No.:
- 1N4495US/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, A
- Datasheet:
-
1N4495US/TR.pdf
- Description:
- DIODE ZENER 180V 1.5W D5A
- Quantity:
- Payment:
- Shipping:
Inventory:100
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Product details
Overview
1N4495US/TR from Microsemi is a hermetically sealed, voidless glass MELF (D-5A) surface-mount Zener diode rated for 1.5 W steady-state power dissipation, with a nominal Zener voltage of 180 V at 1.4 mA test current, ±5% tolerance, and maximum dynamic impedance of 1300 Ω at IZT. It is qualified to MIL-PRF-19500/406 at JANTXV level and used in high-reliability voltage regulation for aerospace power conditioning circuits.
For engineers reviewing the 1N4495US/TR datasheet, 1N4495US/TR pinout, 1N4495US/TR application, or 1N4495US/TR equivalent, this page delivers verified electrical specs, military-grade qualification context, thermal derating behavior, cathode-band polarity marking, and direct alternatives for radiation-hardened or high-temp stable reference designs.
Technical Context
This device operates as a precision voltage reference in reverse-biased breakdown mode, with Zener voltage specified at IZT = 1.4 mA and guaranteed regulation over -65°C to +175°C junction temperature range. Its voidless glass construction and Category I metallurgical bond ensure long-term stability under thermal cycling and mechanical stress.
The 1N4495US/TR exhibits a maximum reverse leakage current of 0.25 µA at 144 V (80% VZ) and a forward voltage of ≤1.5 V at 1.0 A, supporting bidirectional protection and clamping roles. Thermal resistance junction-to-end cap is 20°C/W, enabling predictable power derating above 25°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 180 V ±5% at IZT = 1.4 mA - defines precise regulation point for high-voltage biasing and reference generation |
| Power Dissipation (PD) | 1.5 W @ TA = 25°C - sets maximum continuous DC power handling before thermal derating applies |
| Junction Temperature Range | -65°C to +175°C - enables operation in extreme environments including space and engine bay electronics |
| Dynamic Impedance (ZZT) | 1300 Ω @ IZT - indicates voltage regulation sensitivity to current variation; critical for low-noise reference stability |
| Reverse Leakage (IR) | 0.25 µA @ 144 V - ensures minimal parasitic current in high-impedance sensing or standby circuits |
| Forward Voltage (VF) | ≤1.5 V @ 1.0 A - supports use as bidirectional clamp or surge limiter in transient protection schemes |
| Thermal Resistance (RθJEC) | 20°C/W - allows accurate junction temperature estimation from end-cap temperature measurement |
Pinout & Package
Package: Hermetically sealed voidless glass MELF (D-5A) case with tungsten slugs; cathode indicated by single black band; terminals plated with Sn/Pb or RoHS-compliant matte tin (commercial only); weight: 193 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side connection in Zener regulator | Connected to lower potential node; carries full load current during reverse regulation |
| Cathode | Zener breakdown terminal / high-side connection in regulator | Marked by black band; referenced to regulated output voltage; must be held at higher potential than anode |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Prevents moisture ingress and internal corrosion, ensuring >20-year reliability in sealed avionics enclosures |
| Category I metallurgical bond | Validated bond integrity per MIL-PRF-19500/406 for 1N4462US–1N4496US series, eliminating interfacial delamination risk |
| MIL-PRF-19500/406 qualification | JANTXV-level screening includes burn-in, temperature cycling, and lot acceptance testing for mission-critical systems |
| Triple-layer passivation | Reduces surface leakage and enhances stability under high humidity and ionizing radiation exposure |
| Radiation hardness | Inherently tolerant to total ionizing dose (TID) per Microsemi MicroNote 050 - suitable for low-earth orbit applications |
Applications
| Avionics Power Conditioning | Satellite Voltage Reference |
|---|---|
Use Scenario: Regulating auxiliary bus voltage in flight control computers where failure is not tolerable. IC Role / Device Role / Timing Role: Zener diode operating in reverse breakdown to clamp and stabilize 180 V rail against transients and load variation. Use Value: Maintains ±0.5% output stability across -55°C to +125°C ambient with no drift-induced calibration loss. | Use Scenario: Providing stable reference for ADC biasing in star tracker telemetry subsystems. IC Role / Device Role / Timing Role: High-voltage reference element in precision voltage divider networks feeding analog front-ends. Use Value: Delivers <10 ppm/°C tempco and <0.1% long-term drift due to hermetic sealing and radiation-hard construction. |
| Nuclear Instrumentation | High-Temp Industrial Sensors |
Use Scenario: Biasing photomultiplier tube (PMT) anode chains in radiation detection modules. IC Role / Device Role / Timing Role: Series-connected Zener string establishing graded high-voltage distribution up to 1.8 kV. Use Value: Enables 1000+ hour operation at 150°C junction temperature without parameter shift or parametric failure. | Use Scenario: Voltage clamping in downhole logging tools exposed to 175°C wellbore environments. IC Role / Device Role / Timing Role: Overvoltage protector for signal conditioning ICs interfacing with piezoelectric sensors. Use Value: Survives repeated thermal shock cycles (-65°C ↔ +175°C) while retaining Zener voltage within spec limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4495US | Same die, identical specs, but supplied in bulk (non-tape/reel) packaging | No tape-and-reel support; unsuitable for automated SMT placement | Select 1N4495US/TR when requiring EIA-481-B compliant tape-and-reel delivery for pick-and-place assembly |
| 1N4495 | Same electrical specs but in DO-41 axial-leaded package; lacks MIL-PRF-19500/406 qualification | Not suitable for high-reliability or space-constrained SMT layouts | Choose 1N4495US/TR over 1N4495 when hermetic MELF packaging and JANTXV screening are mandatory |
Compared with 1N4495US and 1N4495, the 1N4495US/TR uniquely combines tape-and-reel manufacturability, MIL-qualified reliability, and surface-mount compatibility-enabling drop-in integration into high-integrity SMT production lines without requalification.
Availability
1N4495US/TR is available at Aetrix Electronics and suitable for avionics power conditioning, satellite voltage reference, nuclear instrumentation, and high-temp industrial sensors requiring stable component supply across extended lifecycle programs.
Supply support for 1N4495US/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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability, radiation-hardened, and defense-grade analog and mixed-signal components.
The 1N4495US/TR belongs to Microsemi's military-qualified Zener diode family designed specifically for voltage regulation in mission-critical aerospace, defense, and nuclear systems where parameter stability and long-term reliability are non-negotiable.
FAQ
What is the Zener voltage tolerance for the 1N4495US/TR?
The 1N4495US/TR has a nominal Zener voltage of 180 V with a standard tolerance of ±5%, as confirmed in the Electrical Characteristics table on page 3 of Microsemi document T4-LDS-0183-1. No suffix indicates 5% tolerance; tighter 1% or 2% versions use D or C suffixes respectively - the 1N4495US/TR uses no tolerance suffix and therefore conforms strictly to ±5%.
Is the 1N4495US/TR RoHS compliant?
The 1N4495US/TR is available in RoHS-compliant versions only for commercial-grade units, per Microsemi documentation stating "RoHS compliant versions available (commercial grade only)." Since the part number includes no RoHS designation (e.g., e3 suffix), and JANTXV qualification implies military-grade build, the 1N4495US/TR is non-RoHS compliant and uses Sn/Pb terminations as standard.
What does the "TR" suffix mean in 1N4495US/TR?
The "TR" suffix in 1N4495US/TR denotes tape-and-reel packaging per EIA-481-B standard, enabling automated surface-mount assembly. This distinguishes it from the same-die 1N4495US (bulk packaged) and confirms compliance with industry-standard reel dimensions, orientation, and carrier tape specifications required for SMT line integration.
What is the maximum reverse leakage current for the 1N4495US/TR?
The maximum reverse leakage current for the 1N4495US/TR is 0.25 µA at 144 V (80% of nominal VZ), as specified in the Electrical Characteristics table. This value is measured at 25°C case temperature and reflects the device's ultra-low leakage performance essential for high-impedance reference and sensing applications.
Does the 1N4495US/TR require derating above 25°C ambient?
Yes, the 1N4495US/TR requires linear power derating above 25°C ambient, per Figure 2 (Temperature-Power Derating Curve). With RθJEC = 20°C/W, its usable power drops to zero at 100°C case temperature. For example, at 75°C case temperature, maximum allowable power is reduced to 0.75 W - critical for thermal design in enclosed avionics enclosures.
1N4495US/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- SQ-MELF, A
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 180 V
- Tolerance:
- ±5%
- Power - Max:
- 1.5 W
- Impedance (Max) (Zzt):
- 1300 Ohms
- Current - Reverse Leakage @ Vr:
- 250 nA @ 144 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:
- D-5A
1N4495US/TR FAQ
1.How can I place an order for 1N4495US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4495US/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 1N4495US/TR reliable?
The price and inventory of 1N4495US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4495US/TR is usually 5 days.
3.What payment methods are accepted for 1N4495US/TR?
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Note: Certain payment methods may incur a processing fee.
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1N4495US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4495US/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 1N4495US/TR?
For technical support, including 1N4495US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4495US/TR requirements.
6.How does Aetrix verify that 1N4495US/TR is sourced from the original manufacturer or authorized distributors?
All 1N4495US/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 1N4495US/TR meets industry standards.
7.What is the process for return or replacement of 1N4495US/TR?
All 1N4495US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4495US/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 1N4495US/TR part is unused and in its original packaging.
Return procedure for 1N4495US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4495US/TR Tags
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