The R1275NC21L is a high-power thyristor designed for fast switching and efficient power control. Made by IXYS UK Westcode (Littelfuse), it works well in induction heating, UPS systems, and high-frequency inverters. With 2100V voltage, 1275A current, and a 65µs turn-off time, it ensures stable and reliable performance. This article covers its features, uses, benefits, and important buying factors to help you choose the right component.
Catalog
The R1275NC21L
is a high-performance distributed gate thyristor designed for demanding power applications, including induction power supplies, high-frequency inverters, UPS systems, and pulse power circuits. Manufactured by IXYS UK Westcode, this device features a repetitive peak off-state voltage of 2100V, an average on-state current of 1275A, and a peak surge on-state current of 15,500A. Its advanced distributed gate structure and lifetime control ensure high di/dt capability, fast recovery, and low on-state voltage drop, making it ideal for high-efficiency power conversion.
With a turn-off time of 65µs, a thermal resistance of 0.024 K/W, and a recovered charge of 940µC, the R1275NC21L delivers reliable performance under extreme conditions. Its optimized design supports high-frequency switching while maintaining thermal stability and durability. Order your bulk quantities today to secure the best pricing and ensure uninterrupted supply for your power electronics applications.
The R1275NC21L is a distributed gate thyristor developed by IXYS UK Westcode, a subsidiary of Littelfuse. IXYS UK Westcode specializes in high-power semiconductor devices, offering a range of products designed for demanding applications. The R1275NC21L exemplifies their expertise in distributed gate technology, providing high di/dt capability and efficient performance.
Parameter Name and Symbol
|
Value and Unit
|
Repetitive Peak Off-State Voltage (VDRM)
|
2100 V
|
Repetitive Peak Reverse Voltage (VRRM)
|
1800 V
|
Average On-State Current at (ITAV) Tk=55°C(A)
|
1275 A
|
Surge On-State Current ITSM (10ms Half Sine
Wave (A)
|
15500 A
|
Surge Withstand Energy I2t (Thy) (A2s)
|
1.20×106
|
Turn-off Time (Tq)
|
65 µs
|
Reverse Recovery Charge (Qrr)
|
940 µC
|
Package Type
|
W11
|
Threshold Voltage (V0)
|
1.207 V
|
On-State Resistance (rS)
|
0.342 mΩ
|
Junction-to-Case Thermal Resistance RthJK 180 °C Sine Wave
|
0.024 K/W
|
• High di/dt Capability: The unique distributed gate design and lifetime control features provide high di/dt capability, ensuring efficient performance in demanding applications.
• Fast Turn-Off: The device exhibits a turn-off time (tq) of 65 µs, facilitating rapid switching operations.
• Low On-State Voltage Drop: Maintains a low on-state voltage drop, enhancing overall system efficiency.
• Robust Surge Handling: Capable of withstanding a peak surge on-state current of 15,500 A for a 10 ms half-sine wave, indicating strong surge current handling.
• Thermal Efficiency: Features a thermal resistance junction to case of 0.024 K/W, promoting effective heat dissipation.
• Induction Power Supplies: Utilized in induction heating systems for efficient power control and rapid switching.
• High-Frequency Inverters/Converters: Ideal for applications demanding high-speed switching and robust performance.
• Uninterruptible Power Supplies (UPS): Ensures reliable power delivery and quick response to load changes.
• Pulse Power Applications: Suitable for systems requiring precise control of high-current pulses.

The packaging dimensions of the R1275NC21L are clearly defined in the outline drawing, providing critical details for installation and integration into electronic systems.
The top view of the device reveals a maximum outer diameter of 74mm, with a central hole for mounting. The 4.75mm blade connector, positioned at an angle of 20° ± 5°, serves as the primary electrical connection. This connector ensures reliable contact while maintaining a compact layout.
From the side view, the threaded body is an essential structural feature, allowing for secure mounting and efficient thermal dissipation. The compressed height is specified as 27.7mm, ensuring a compact profile when properly installed. A minimum height of 25.9mm is maintained even under compression, providing a consistent mechanical footprint.
For electrical functionality, the gate terminal follows the AMP receptacle standard 60598-1, ensuring compatibility with standard connectors. The cathode and anode feature two mounting holes with a minimum depth of 3.6mm to 3.5mm × 2.3mm, ensuring stable attachment and effective current conduction.
The creep path over convolution is specified as 25.4mm minimum, ensuring proper insulation and reducing the risk of electrical leakage. This design enhances reliability in high-voltage applications by maintaining safe insulation distances.
Advantages
• High di/dt Capability: The distributed gate design and lifetime control allow for fast and efficient current switching, making it ideal for high-power applications.
• Fast Turn-Off: With a turn-off time of 65 µs, this thyristor ensures quick and precise switching, reducing delays in high-frequency operations.
• Low On-State Voltage Drop: Operates with minimal voltage loss, improving overall efficiency and reducing power consumption.
Considerations
• Heat Dissipation: Since the thermal resistance (RthJK) is 0.024 K/W, proper cooling measures are necessary to prevent overheating and ensure long-term reliability.
• Application Fit: While well-suited for high-power circuits, verifying compatibility with system requirements is crucial to maximize performance and longevity.
• Voltage and Current Ratings – Ensure the repetitive peak off-state voltage (2100V) and average on-state current (1275A) match your application’s power requirements.
• Switching Speed – With a turn-off time of 65 µs, this thyristor is ideal for high-speed switching applications, but verify if it meets your specific timing needs.
• Thermal Management – The thermal resistance (0.024 K/W) requires an effective cooling system to prevent overheating and ensure durability.
• Surge Handling – If your application involves high inrush currents, the peak surge on-state current of 15,500A is a key benefit, but confirm it aligns with your circuit protection measures.
• Application Suitability – This thyristor is designed for induction heating, UPS systems, and high-frequency converters, so ensure it fits your system’s design and load conditions.
• Supplier and Availability – Purchase from authorized distributors to guarantee product authenticity and availability for bulk orders.
• Inadequate Gate Drive
Issue: Insufficient gate current can lead to suboptimal device performance or failure to trigger.
Resolution: Ensure the gate drive circuit provides a peak gate current (IGM) between five and ten times the gate trigger current (IGT). The gate drive should have an open-circuit voltage of at least 30V, with a current rise rate of 4A/µs. The pulse duration (tp1) should be at least 20µs or sufficient to allow the anode current to reach ten times the latching current (IL), whichever is greater.
• Thermal Management Challenges
Issue: Excessive junction temperatures can degrade performance or damage the device.
Resolution: Implement effective cooling solutions to maintain the junction temperature within specified limits. Utilize heat sinks or active cooling systems to manage the thermal resistance junction to case (RthJK) of 0.024 K/W.
• High di/dt Stress
Issue: Rapid current changes can induce electrical stress, potentially leading to device failure.
Resolution: Design the circuit to limit the rate of current rise (di/dt) within the device's specified capabilities. Ensure the gate drive provides adequate current to handle high di/dt conditions.
• Voltage Transients
Issue: Transient overvoltages can exceed the device's voltage ratings, causing breakdown.
Resolution: Incorporate snubber circuits or varistors to suppress voltage transients and protect the thyristor from overvoltage conditions.
Both the R1275NC21L and R1275NC21J are high-power distributed gate thyristors manufactured by IXYS UK Westcode. They share similar core specifications, including 2100V repetitive peak off-state voltage, 1275A average on-state current, and 15,500A peak surge on-state current. However, their primary difference lies in their turn-off time.
The R1275NC21L has a turn-off time of 65µs, making it suitable for applications that require high efficiency, stable switching, and thermal durability. It is often used in induction power supplies, UPS systems, high-frequency inverters, and pulse power circuits.
On the other hand, the R1275NC21J features a faster turn-off time of 50µs, making it a better choice for high-speed switching applications that demand quick response and lower switching losses. It is ideal for power electronics where minimizing delays is crucial.
Both devices have the same thermal resistance (0.024 K/W), meaning proper cooling and heat dissipation are necessary in either case. The choice between these two models depends mainly on whether the application prioritizes faster switching speed (R1275NC21J) or overall stability and efficiency (R1275NC21L).
Brand
|
Model
|
Features
|
IXYS
|
R1271NS12B
|
2100V, 1275A, 50µs turn-off time, faster switching
|
IXYS
|
R1275NC20L
|
2000V, 1275A, 65µs turn-off time, slightly lower voltage
|
IXYS
|
R1275NC21M
|
2100V, 1275A, 70µs turn-off time, slightly slower
switching
|
The R1275NC21L is a dependable and efficient choice for high-power applications, offering fast response and strong surge handling. While proper cooling is needed, its low voltage drop and quick switching make it ideal for demanding power circuits. Reach out now for bulk orders and to ensure quality and a steady supply for your projects.
Datasheet PDF
R1275NC21L Datasheets:
R1275NC21L Details PDF
R1275NC21L Details PDF for KR.pdf
R1275NC21L Details PDF for IT.pdf
R1275NC21L Details PDF for ES.pdf
R1275NC21L Details PDF for DE.pdf
R1275NC21L Details PDF for FR.pdf
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