Thyristors offer high blocking voltage and dv/dt immunity.

Press Release Summary:

With 800 V minimum rated blocking voltage, max turn-on time as low as 25 µs, and minimum rated static dv/dt of up to 75 V/µs, EV Series Teccor Thyristors can survive transient voltages, minimize false triggering, and prevent unstable activation. Series includes 0.8 A and 1.5 A sensitive gate silicon controlled rectifiers, as well as 0.8 A and 1.0 A sensitive gate triacs. RoHS-compliant units are suited for GFCI, AFCI, ALCI, and LCDI applications.

Original Press Release:

Littelfuse Announces New Fast-Switching Teccor® Thyristors

New triacs and SCRs provide enhanced dv/dt and switching performance.

DES PLAINES, IL -- May 6, 2008 - Littelfuse, Inc. (NASDAQ/NGS:LFUS) today introduced the EV Series - Enhanced Version Teccor brand Thyristors. These thyristors feature a minimum rated blocking voltage (Vdrm/Vrrm) of up to 800 V, a maximum turn-on time (tq) as low as 25 µs, and a minimum rated static dv/dt of up to 75 V/µs - a five times improvement over earlier thyristors of this type.

The high blocking voltage and dv/dt immunity are attractive to designers creating circuits for high-stress and/or high-reliability applications. These features help a triac to better survive transient voltages, minimize false triggering, and prevent unstable activation. For example, one of the more common failure mechanisms in thyristors is a permanent short caused by a transient that exceeds the dv/dt rating.

In addition to being more robust, this feature helps prevent excess energy from being passed to the circuit or load being protected. Fast turn-on time is important in applications such as ground fault circuit interruption, where it helps ensure proper operation of the associated electromechanical breaker.

Reduced Component Count
The enhanced switching characteristics of the EV Series also minimize the need for extra components for circuit protection. To compensate for lower dv/dt, designers previously had to resort to the use of snubber circuits, typically by adding resistance and capacitance across the main terminals of the triac or SCR. These can now be eliminated in many applications.

Suggested applications include fault detection circuits, such as Ground Fault Circuit Interrupt (GFCI), Arc Fault Circuit Interrupt (AFCI), Appliance Leakage Current Interrupt (ALCI), Leakage Current Detection Interrupt (LCDI), etc. The new thyristors also offer advantages in direct spark igniter circuits (flame ignition), white goods control boards (solenoid, valve, pump, and heater controls) and small appliances (small motor and heating controls).

The new EV Series of thyristors includes four families:
The SxX8xSx EV family of 0.8 amp sensitive gate SCRs
The Sx02xS EV family of 1.5 amp sensitive gate SCRs
The LX8 EV family of 0.8 amp sensitive gate triacs
The L01 EV family of 1.0 amp sensitive gate triacs

The 0.8 amp families are suitable for most applications, while the 1.5 amp families are for applications with higher current and/or thermal demands.

The newly released products come in a full range of gate sensitivities and industry standard packaging variations, and are pin-to-pin compatible with popular models already in use. They are RoHS (Restrictions On Hazardous Substances) compliant.

Samples are available immediately. Typical lead time for production quantities is eight to ten weeks, although aggressive customer lead time expectations can be accommodated.

Additional Information
For additional information, please visit, or contact an authorized products distributor or the Littelfuse Technical Support line at 1-800-999-9445.

About Littelfuse
As the worldwide leader in circuit protection products and solutions with annual sales of $536.1 million in 2007, the Littelfuse portfolio is backed by industry leading technical support, design and manufacturing expertise. Littelfuse products are vital components in virtually every product that uses electrical energy, including automobiles, computers, consumer electronics, handheld devices, industrial equipment, and telecom/datacom circuits. Littelfuse offers Teccor®, Wickmann® and Pudenz® brand circuit protection products. In addition to its Des Plaines, Illinois, world headquarters, Littelfuse has sales, distribution, manufacturing and engineering facilities in Brazil, China, England, Germany, Hong Kong, India, Ireland, Japan, Korea, Mexico, the Netherlands, the Philippines, Singapore, Taiwan and the U.S. For more information, please visit Littelfuse's web site at

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