MRO Magazine

Littelfuse Adds Two Unidirectional SIDAC Switching Thyristors Optimized for Capacitor Discharge Applications

By Business Wire News   


Littelfuse, Inc., the global leader in circuit protection, has introduced two new product series, the Kxxx0S1URP and Kxxx0GURP Series Unidirectional SIDAC Switching Thyristors. A SIDAC (short for Silicon Diode for Alternating Current) is a semiconductor switch used in conjunction with a capacitor and a transformer in capacitor discharge ignition (CDI) circuits for generating high voltage spikes. The Kxxx0S1URP and Kxxx0GURP Series offer lower switching losses than existing high-energy SIDAC and standard SIDAC products. A new SIDAC design provides a higher repetitive pulse current (ITRM) rating at higher ambient temperatures, improved breakover/trigger voltage vs. temperature characteristics, and lower switching loss. This allows existing circuits to support higher voltage outputs, and ensures stable voltage outputs at high ambient temperatures.

Typical applications for the Kxx0yU Series SIDAC/Unidirectional Thyristors include high-power flame ignition modules designed for gas cooking appliances ranging from portable, tabletop types to commercial-grade multiple-burner models, gas water heaters and oil heaters of all sizes, and ion generators.

“In a typical high-power gas ignition circuit, the SIDAC acts like a switch to discharge energy from the capacitor rapidly,” said Daisy Wang, product marketing manager for the line. “The high instantaneous rate of current change (di/dt) of the pulse current from the discharge drives a high pulse voltage output on the secondary side of the transformer to create an ignition spark in the spark gap.”

Kxxx0S1URP and Kxxx0GURP Series Unidirectional SIDACs offer these key benefits:

  • Lower switching loss (VT) than existing SIDAC series while keeping high 280A pulse capability allows generating longer high-voltage pulses or generating multiple outputs by supporting higher discharge current.
  • Improved break over/trigger voltage (VBO) vs. temperature characteristics means there is no degradation of the pulse voltage at high ambient temperatures.
  • High junction temperature (TJ) of 150˚C (for part numbers K2200,K 2300, K2400 and K2500) ensures longer field life and high reliability in the high ambient temperatures common in gas ignition modules of cooktops and water heaters/boilers.
  • Lower IBO/faster switching than existing Kxxx0SHURP/GHURP Series allows for a higher instantaneous rate of current change (di/dt) in the discharge current pulse, resulting in a higher voltage output.


The Kxxx0S1URP and Kxxx0GURP Series Unidirectional SIDACs are available in either a robust DO-15 axial package or a compact SMA (DO-214AC) surface mount package. The axial DO-15 version is available sold in tape-and-reel packed in quantities of 1,000 or 5,000. The surface mount version is provided in tape-and-reel packaging in quantities of 5,000. Sample requests can be placed through authorized Littelfuse distributors worldwide. For a listing of Littelfuse distributors, please visit the Contact Us page on

For More Information

Additional information is available on the Kxxx0yU Series product page. If you have technical questions, please contact: Daisy Wang, product marketing manager,

About Littelfuse

Founded in 1927, Littelfuse is the world leader in circuit protection with growing global platforms in power control and sensing. The company serves global customers in the electronics, automotive and industrial markets with technologies including fuses, semiconductors, polymers, ceramics, relays and sensors. Littelfuse has over 8,000 employees in more than 35 locations throughout the Americas, Europe and Asia. For more information, please visit the Littelfuse website:

For high resolution image click here: Kxxx0S1URP and Kxxx0GURP Series Unidirectional SIDACs


Littelfuse, Inc.
Rhonda Stratton, 773-628-0644
Global Marketing Communications Manager, Electronics Products


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