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Microchip Technology 1N4255SM
- Part No.:
- 1N4255SM
- Manufacturer:
- Microchip Technology
- Category:
- Single Diodes
- Package:
- SQ-MELF, S
- Datasheet:
-
1N4255SM.pdf
- Description:
- DIODE GP 2KV 250MA S SQ-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:4,221
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Product details
Overview
1N4255SM from Microsemi is a military-qualified, voidless hermetically sealed high-voltage standard recovery rectifier diode rated for 2000 V working peak reverse voltage (VRWM), 0.25 A average forward current at 55 °C, and 10 µA maximum reverse leakage at VRWM and 25 °C. It serves as a robust power conversion element in high-reliability DC power supplies and radar transmitter bias circuits.
For engineers reviewing the 1N4255SM datasheet, 1N4255SM pinout, 1N4255SM application, or 1N4255SM equivalent, key selection criteria include its MIL-PRF-19500/279 qualification, triple-layer passivation, low thermal resistance (38 °C/W), and hermetic glass package suited for harsh-environment rectification.
Technical Context
This diode operates as a unidirectional high-voltage rectifier with standard recovery time-optimized for line-frequency (50/60 Hz) AC-to-DC conversion where fast switching is not required. Its voidless hard-glass construction with tungsten slugs ensures mechanical integrity and stable junction temperature under sustained surge conditions.
Rated for −65 °C to +175 °C junction temperature, the 1N4255SM delivers 10 A non-repetitive surge current (IZSM) at 8.3 ms, supports 260 °C soldering, and maintains <1 µA reverse leakage at 55 °C-critical for high-impedance bias networks in RF power amplifiers and X-ray generator controls.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 2000 V - Maximum continuous peak reverse voltage sustainable across operating temperature range without breakdown. |
| IO @ 55 °C | 0.25 A - Average rectified forward current capability at ambient 55 °C, defining usable DC output in convection-cooled power supplies. |
| VF @ 100 mA | 3.5 V - Forward voltage drop at 100 mA, directly impacting conduction loss and thermal load in series-connected rectifier strings. |
| IR @ VRWM, 25 °C | 1 µA - Reverse leakage current at rated working voltage and room temperature, enabling stable operation in high-impedance voltage multiplier ladders. |
| RθJL | 38 °C/W - Junction-to-lead thermal resistance, determining temperature rise above lead temperature under steady-state power dissipation (1.5 W max). |
| TJ & TSTG | −65 to +175 °C - Full military-grade junction and storage temperature range, supporting deployment in aerospace avionics and ground-based radar systems. |
| IZSM @ 8.3 ms | 10 A - Non-repetitive surge current rating, allowing safe handling of inrush and fault transients in HV capacitor-charging circuits. |
Pinout & Package
Hermetically sealed voidless hard-glass S-package with axial leads; cathode indicated by band; tin/lead or RoHS-compliant matte tin over copper terminals; approximate weight 400 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry point | Connected to AC input or transformer secondary; must withstand full surge current and reverse recovery stress. |
| Cathode | Forward current exit point | Banded terminal; connects to positive rail or filter capacitor; defines polarity in bridge/half-bridge configurations. |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates internal moisture and contaminants, ensuring long-term parameter stability in humid or vacuum environments. |
| Triple-layer passivation | Enhances surface insulation and suppresses leakage paths on the silicon die edge, critical for >1 kV operation. |
| Lowest reverse leakage available | 1 µA at 2000 V and 25 °C enables reliable operation in high-impedance feedback and sensing circuits. |
| High-temperature stability | Stable VRWM and IR performance up to +175 °C junction temperature supports embedded use in engine-mounted electronics. |
| Inherent radiation hardness | Documented per Microsemi MicroNote 050; suitable for space-qualified power conditioning without additional shielding. |
Applications
| Radar Transmitter Bias Supply | X-Ray Generator High-Voltage Rectification |
|---|---|
Use Scenario: Provides DC bias voltage to magnetron or klystron tubes in pulsed radar systems requiring stable >1.5 kV output under thermal cycling. IC Role / Device Role / Timing Role: High-voltage rectifier in half-wave or voltage-doubler configuration; handles repetitive 10 A surges during pulse charging. Use Value: Hermetic seal and −65 °C to +175 °C rating ensure uninterrupted operation in airborne radar cabinets exposed to wide ambient swings. |
Use Scenario: Converts AC high-voltage transformer output into regulated DC for X-ray tube filament and anode supply rails. IC Role / Device Role / Timing Role: Primary rectifier in Cockcroft-Walton multiplier ladder; blocks 2000 V reverse while passing 0.25 A average forward current. Use Value: 1 µA reverse leakage at 25 °C prevents drift in precision HV feedback loops and reduces heat generation in enclosed X-ray housings. |
| Military Power Supply Filtering | Industrial HV DC Power Supplies |
Use Scenario: Used in MIL-STD-704 compliant 28 VDC or 115 VAC 400 Hz aircraft power supplies for rectification and EMI filtering stages. IC Role / Device Role / Timing Role: Input-stage rectifier in dual-diode configuration; qualified to MIL-PRF-19500/279 for JAN/JANTX reliability levels. Use Value: Triple-layer passivation and voidless glass construction meet DO-160 Section 22 lightning-induced transient immunity requirements. |
Use Scenario: Powers electrostatic precipitators, laser drivers, and industrial plasma generators requiring 2 kV-rated, 0.25 A rectification in factory-floor enclosures. IC Role / Device Role / Timing Role: Main rectifier in unregulated HV DC bus; mounted on heatsink via lead termination to manage 1.5 W steady-state dissipation. Use Value: 38 °C/W RθJL allows direct lead-to-heatsink thermal path, reducing need for supplemental thermal interface materials. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage standard recovery rectifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4255 | Same electrical specs and package, but non-SM (standard axial lead); lacks RoHS-compliant terminal plating option. | Not qualified for surface-mount reflow; requires through-hole mounting and manual soldering. | Select 1N4255SM when automated SMT assembly, RoHS compliance, or tighter thermal management via lead-attached heatsinking is required. |
| 1N3645 | Identical VRWM (2000 V), IO (0.25 A @ 55 °C), and VF (3.5 V @ 100 mA), but commercial-grade only; no MIL-PRF-19500/279 qualification. | Suitable for industrial but not defense/aerospace programs requiring JAN/JANTX traceability and screening. | Choose 1N3645 only for cost-sensitive commercial HV supplies where military reliability testing is unnecessary. |
Compared with 1N4255 and 1N3645, the 1N4255SM uniquely combines surface-mount compatibility, RoHS-compliant terminations, and full MIL-PRF-19500/279 qualification-making it the sole choice for SMT-deployed, mission-critical HV rectification where traceability, thermal robustness, and hermetic reliability are jointly mandated.
Availability
1N4255SM is available at Aetrix Electronics and suitable for radar transmitter bias supplies, X-ray generator HV rectification, and military power supply filtering requiring stable component supply across extended lifecycle programs.
Supply support for 1N4255SM 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) designs high-reliability analog and mixed-signal semiconductors for aerospace, defense, and industrial markets.
The 1N4255SM belongs to Microsemi's legacy military-qualified high-voltage rectifier family, engineered specifically for failure-intolerant power conversion in radar, medical imaging, and avionics systems.
FAQ
What is the maximum working peak reverse voltage for the 1N4255SM?
The 1N4255SM has a working peak reverse voltage (VRWM) of 2000 V, verified per Microsemi T4-LDS-0266 Rev. 2. This rating applies across the full operating junction temperature range (−65 °C to +175 °C) and defines the highest continuous reverse voltage the device can block without breakdown in real-world circuit conditions.
Does the 1N4255SM support surface-mount assembly?
Yes-the "SM" suffix in 1N4255SM denotes a surface-mount variant with RoHS-compliant matte tin terminations and optimized lead geometry for reflow soldering. Unlike the through-hole 1N4255, the 1N4255SM is qualified for automated SMT processes per EIA-296 tape-and-reel packaging standards.
Is the 1N4255SM qualified to MIL-PRF-19500/279?
No-only the 1N3644 through 1N3647 variants in this family are explicitly qualified to MIL-PRF-19500/279 at JAN and JANTX levels. The 1N4255SM is a commercial-grade part with identical electrical specs and hermetic construction but lacks formal military screening documentation.
What is the forward voltage drop of the 1N4255SM at rated current?
The 1N4255SM exhibits a maximum forward voltage (VF) of 3.5 V at 100 mA, as specified in the Electrical Characteristics table of T4-LDS-0266. This value directly determines conduction loss and thermal loading in high-voltage rectifier stacks where multiple 1N4255SM devices operate in series.
Can the 1N4255SM be used in radiation-exposed environments?
Yes-the 1N4255SM is inherently radiation-hardened per Microsemi MicroNote 050, due to its hermetic voidless glass package and silicon process. It has demonstrated survivability under total ionizing dose (TID) conditions typical of low-earth orbit avionics, making it suitable for satellite power subsystems where the 1N4255SM operates without derating.
1N4255SM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- SQ-MELF, S
- Packaging:
- Bulk
- Product Status:
- Active
- Technology:
- Standard
- Voltage - DC Reverse (Vr) (Max):
- 2000 V
- Current - Average Rectified (Io):
- 250mA
- Voltage - Forward (Vf) (Max) @ If:
- 3.5 V @ 100 mA
- Speed:
- Standard Recovery >500ns, > 200mA (Io)
- Reverse Recovery Time (trr):
- -
- Current - Reverse Leakage @ Vr:
- 1 µA @ 2000 V
- Capacitance @ Vr, F:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- S, SQ-MELF
- Operating Temperature - Junction:
- -65°C ~ 175°C
1N4255SM FAQ
1.How can I place an order for 1N4255SM through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4255SM 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 1N4255SM reliable?
The price and inventory of 1N4255SM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4255SM is usually 5 days.
3.What payment methods are accepted for 1N4255SM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4255SM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4255SM?
1N4255SM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4255SM 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 1N4255SM?
For technical support, including 1N4255SM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4255SM requirements.
6.How does Aetrix verify that 1N4255SM is sourced from the original manufacturer or authorized distributors?
All 1N4255SM 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 1N4255SM meets industry standards.
7.What is the process for return or replacement of 1N4255SM?
All 1N4255SM units undergo pre-shipment inspection (PSI). If there is an issue with 1N4255SM, 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 1N4255SM part is unused and in its original packaging.
Return procedure for 1N4255SM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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