New Industry Products

Littelfuse’s New Series of Thyristors Guard Against Severe Voltage Transients

April 07, 2022 by Gary Elinoff

The SIDACtor series from Littelfuse will provide protection for exposed interfaces in industrial and information communications technology (ICT) applications.

Members of Littelfuse’s Pxxx0S3N SIDACtor series, announced Tuesday, are compact semiconductor devices that provide high surge overvoltage protection. This type of defensive shield is necessary for manufacturers who must contend with increasingly demanding international safety and protection requirements.


SIDACtor Series

The Pxxx0S3N SIDACtor series. Image used courtesy of Littelfuse


The new units are designed to provide 3 kA protection against 8/20 pulses, which are generally induced by lightning and reach 90% of peak value in 8 µs, before retreating to 50% in 20 µs. The devices also sport low thermal accumulation during long-term overvoltage events. 


The Demands of Miniaturization

Relentless miniaturization creates an ever more urgent demand for components of greater power density. With its latest series, Littelfuse has responded. 

Per Ben Huang, the company’s Senior Product Marketing Manager of its protection semiconductor business, “Compared to MOVs and TVS diodes, the Pxxx0S3N SIDACtor is significantly smaller, and it is the first product of its size to provide such high surge current protection in such a small package.” 


Advantages of the Pxxx0S3N Series

A vital advantage of the Pxxx0S3N is that its switching voltage (VS) is much lower than gas discharge tubes (GDTs). What’s more, the on-state voltage (VT) is much lower than that of metal oxide varistors (MOVs) and transient voltage suppressor (TVS) diodes. 


Gas Discharge Tubes Littelfuse

Littelfuse also produces GDTs; Here, a member of its CG5 series. Image used courtesy of Littelfuse


Littelfuse notes that the new series are the first products on the market available in DO-214AB (SMC) packages that can handle 3 kA 8/20 pulses. And, unlike gas discharge tube arresters, these semiconductor devices will not wear out even over multiple transient events.

SIDACtors can be used in series with metal oxide varistors (MOV) for power line protection. Additionally, the series members’ low leakage improves the MOVs’ long-term reliability. 

More detailed specifications regarding each individual series model can be found either via the series page or its data sheet. 


Global Standards 

Littelfuse Pxxx0S3N SIDACtor series members adhere to the following international standards:

  • TIA-968-A
  • TIA-968-B
  • ITU K.20/21 Enhanced Level
  • ITU K.20/21 Basic Level
  • GR 1089 Inter-building
  • GR 1089 Intra-building
  • IEC 61000-4-5, 2nd Ed
  • YD/T 1082
  • YD/T 993YD/T 950 

The components are also Underwriter Labs-recognized. 



The Pxxx0S3N series will serve in applications exposed to hazardous environments. These may include:

  • RS-485 data interfaces 
  • AC and DC power lines in industrial and ICT applications
  • Energy storage systems (ESS) power interfaces
  • DC/AC inverters for solar energy systems 
  • Electric vehicle (EV) charging systems


Physical Considerations

  • Members of the Pxxx0S3N series are available in DO-214AB packages whose maximum dimensions are 8.130 by 6.220 mm
  • Operating Junction Temperature Range id from -65 to +150 °C 


Environmental Concerns 

The units are RoHS-compliant and Halogen-free. 


Feature image used courtesy of Michael Fousert/Unsplash