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Microchip Technology 1N4257/TR
- Part No.:
- 1N4257/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Diodes
- Package:
- S, Axial
- Datasheet:
-
1N4257/TR.pdf
- Description:
- DIODE GP 3KV 250MA S AXIAL
- Quantity:
- Payment:
- Shipping:
Inventory:2,053
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Product details
Overview
1N4257/TR from Microsemi is a military-qualified, voidless hermetically sealed high-voltage standard recovery rectifier diode rated for 3000 V working peak reverse voltage, 0.25 A average forward current at 55 °C, and 0.15 A at 100 °C, with maximum forward voltage of 3.5 V at 100 mA and reverse leakage ≤1 µA at VRWM. It serves as a robust, radiation-hardened rectifier in high-reliability power conversion stages of radar transmitters and X-ray generator supplies.
For engineers reviewing the 1N4257/TR datasheet, 1N4257/TR pinout, 1N4257/TR application, or 1N4257/TR equivalent, this page delivers verified electrical parameters, MIL-PRF-19500/279 qualification status, thermal resistance (38 °C/W), junction temperature range (–65 to +175 °C), and hermetic S-package construction details critical for high-voltage, mission-critical design validation.
Technical Context
This diode operates as a standard-recovery (non-fast, non-ultrafast) rectifier with triple-layer passivation and tungsten slug leads, enabling stable performance under sustained high reverse bias up to 3000 V and transient surge currents of 10 A (8.3 ms sine half-wave). Its voidless glass seal ensures hermeticity essential for aerospace and defense environments where moisture ingress or outgassing must be eliminated.
The 1N4257/TR exhibits low thermal resistance (38 °C/W junction-to-lead) and absolute high-voltage/high-temperature stability, supporting operation across –65 °C to +175 °C with <1 µA reverse leakage at 3000 V and 25 °C. It is not RoHS-compliant by default (TR suffix indicates tape-and-reel commercial version without e3 marking).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 3000 V - Maximum continuous peak reverse voltage sustainable over full temperature range without breakdown. |
| IO @ 55 °C | 0.25 A - Average rectified forward current capability with adequate heatsinking at moderate ambient. |
| IO @ 100 °C | 0.15 A - Derated forward current limit at elevated ambient, defining usable power envelope in compact enclosures. |
| VF @ 100 mA | 3.5 V - Forward voltage drop determining conduction loss and thermal load in high-voltage DC output stages. |
| IR @ VRWM | ≤1 µA @ 25 °C - Ultra-low reverse leakage critical for maintaining voltage hold-off in precision multiplier and pulse circuits. |
| RθJL | 38 °C/W - Junction-to-lead thermal resistance enabling direct lead-frame heat sinking without PCB copper pour. |
| TJ & TSTG | –65 to +175 °C - Full military-grade operating and storage temperature range validated per MIL-PRF-19500/279. |
Pinout & Package
Hermetically sealed S-package (voidless hard glass case with tungsten slugs); cathode indicated by band; tin/lead or RoHS-compliant matte tin terminals over copper; weight ≈ 400 mg; lead length 1.00–1.25 inches.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry point | Connected to AC input or transformer secondary; requires mechanical support due to tungsten slug construction. |
| Cathode | Forward current exit / reverse voltage terminal | Banded end; carries full reverse voltage stress; used as reference node in high-side rectifier configurations. |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Eliminates internal voids and moisture pathways-required for long-term reliability in vacuum, space, and high-humidity military systems. |
| Triple-layer passivation | Enhances surface insulation integrity and suppresses leakage current drift under high electric field stress. |
| Lowest reverse leakage (≤1 µA) | Enables stable DC hold-off in high-impedance voltage multiplier ladders and low-power standby circuits. |
| Inherent radiation hardness | Validated per Microsemi MicroNote 050-no additional shielding needed in TID-sensitive avionics and satellite power systems. |
| High surge current rating (10 A) | Withstands repetitive line surges and capacitor-charging transients in unregulated HV power supplies without degradation. |
Applications
| Radar Transmitter Power Supplies | X-Ray Generator HV Stacks |
|---|---|
Use Scenario: Rectifying pulsed 3–5 kV AC from resonant transformer secondaries into filtered DC for magnetron or klystron anode bias. IC Role / Device Role / Timing Role: High-voltage standard recovery rectifier in voltage-doubler or Cockcroft-Walton ladder configuration. Use Value: 3000 V VRWM and 10 A surge rating ensure reliable turn-on during microsecond pulses without avalanche failure or thermal runaway. |
Use Scenario: Cascaded rectification in multi-stage HV generators producing 50–150 kV DC for X-ray tube acceleration. IC Role / Device Role / Timing Role: Series-connected rectifier in insulated HV stack; each device blocks 3 kV under steady-state and transient conditions. Use Value: ≤1 µA reverse leakage prevents voltage imbalance across series strings; hermetic seal avoids corona-induced degradation in oil-filled housings. |
| Military Half-Bridge Converters | Industrial HV DC Power Supplies |
Use Scenario: Catch diode and freewheeling path in 28 V or 115 VAC-derived 270 VDC bus converters deployed in airborne platforms. IC Role / Device Role / Timing Role: Standard recovery rectifier handling commutation energy in hard-switched topologies with <100 ns turn-off tail. Use Value: –65 to +175 °C junction range and MIL-PRF-19500/279 qualification guarantee operation across flight envelope extremes without derating. |
Use Scenario: Input rectification stage in regulated 3 kV DC industrial plasma generators and electrostatic precipitators. IC Role / Device Role / Timing Role: Primary AC/DC interface component subjected to line surges, harmonics, and ambient temperatures >85 °C. Use Value: 38 °C/W RθJL allows direct lead-frame heatsinking; low thermal resistance maintains safe TJ below 175 °C even with minimal airflow. |
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 |
|---|---|---|---|
| 1N4256 | 2500 V VRWM (vs. 3000 V), identical IO, VF, IR, and package | Suitable where system peak reverse stress is ≤2500 V; lower voltage margin reduces cost and footprint in non-marginal designs | Select 1N4256 only if design margin analysis confirms no transient exceeds 2500 V; retains same thermal and surge behavior. |
| 1N3647 | 3000 V VRWM, but rated 0.25 A @ 55 °C and 0.10 A @ 100 °C (vs. 0.15 A); otherwise identical construction and leakage | Preferred in legacy MIL-PRF-19500/279 JAN/JANTX-qualified systems requiring formal military screening | Choose 1N3647 only when JAN/JANTX certification is contractually mandated; 1N4257/TR offers same voltage rating with higher 100 °C current capability. |
Compared with 1N4256 and 1N3647, the 1N4257/TR provides the highest temperature-rated forward current (0.15 A @ 100 °C) among 3000 V-class variants while retaining full compatibility with S-package mounting and hermetic reliability-making it optimal for thermally constrained, high-reliability HV rectification where both voltage margin and current derating matter.
Availability
1N4257/TR is available at Aetrix Electronics and suitable for radar transmitter power supplies, X-ray generator HV stacks, and military half-bridge converters requiring stable component supply, long-lifecycle assurance, and traceable sourcing.
Supply support for 1N4257/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 high-voltage analog components for defense, aerospace, and industrial markets.
The 1N4257/TR belongs to Microsemi's legacy MIL-PRF-19500/279-qualified high-voltage rectifier family, engineered specifically for mission-critical power conversion where hermetic sealing, voltage stability, and long-term parametric consistency outweigh cost or switching speed requirements.
FAQ
What is the maximum working peak reverse voltage for the 1N4257/TR?
The 1N4257/TR has a working peak reverse voltage (VRWM) of 3000 V, verified per Microsemi T4-LDS-0266 Rev. 2. This rating applies across its full operating temperature range (–65 °C to +175 °C) and defines the maximum continuous sinusoidal or repetitive peak reverse voltage the device can sustain without breakdown or excessive leakage. It is distinct from the non-repetitive peak reverse voltage (VR), which is not specified for the 1N4257/TR in the official datasheet.
Is the 1N4257/TR RoHS compliant?
No, the 1N4257/TR is not RoHS compliant. Per Microsemi documentation, RoHS-compliant versions (marked with "e3") are available only for commercial-grade parts and require explicit ordering with the e3 suffix. The TR suffix denotes tape-and-reel packaging but does not imply RoHS compliance; the base 1N4257/TR uses standard tin/lead termination unless otherwise specified.
What is the forward voltage drop of the 1N4257/TR at rated current?
The 1N4257/TR has a maximum forward voltage (VF) of 3.5 V at 100 mA and 25 °C, as specified in the Electrical Characteristics table of T4-LDS-0266. This value reflects conduction loss under typical high-voltage rectifier operating conditions-not at full average current-and remains stable across temperature due to the device's triple-layer passivation and tungsten slug thermal path.
Does the 1N4257/TR meet MIL-PRF-19500/279 qualification?
No, the 1N4257/TR is not qualified to MIL-PRF-19500/279. According to the datasheet, only the 1N3644–1N3647 series carry JAN or JANTX qualification under that specification. The 1N4257/TR shares identical electrical specs and hermetic S-package construction but is offered as a commercial-grade variant without formal military screening or test documentation required for MIL-PRF-19500/279 compliance.
What is the thermal resistance junction-to-lead for the 1N4257/TR?
The 1N4257/TR has a thermal resistance junction-to-lead (RθJL) of 38 °C/W, measured with a 3/8 inch (10 mm) lead length from the diode body. This low value enables effective heat transfer directly through the tungsten slugs into the PCB or chassis, reducing reliance on external heatsinks in high-voltage, low-duty-cycle applications such as pulse modulators and HV bias supplies.
1N4257/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- S, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Technology:
- Standard
- Voltage - DC Reverse (Vr) (Max):
- 3000 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 @ 3000 V
- Capacitance @ Vr, F:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- S, Axial
- Operating Temperature - Junction:
- -65°C ~ 175°C
1N4257/TR FAQ
1.How can I place an order for 1N4257/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4257/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 1N4257/TR reliable?
The price and inventory of 1N4257/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4257/TR is usually 5 days.
3.What payment methods are accepted for 1N4257/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4257/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4257/TR?
1N4257/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4257/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 1N4257/TR?
For technical support, including 1N4257/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4257/TR requirements.
6.How does Aetrix verify that 1N4257/TR is sourced from the original manufacturer or authorized distributors?
All 1N4257/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 1N4257/TR meets industry standards.
7.What is the process for return or replacement of 1N4257/TR?
All 1N4257/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4257/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 1N4257/TR part is unused and in its original packaging.
Return procedure for 1N4257/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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