Littelfuse – CG6 and CG7 Series Miniature SMT GDTs Protect Against Low to Medium Surges


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Ultra Low Capacitance Makes the CG6 and CG7 Series Ideal for G.Fast Modems and Other High Speed Applications

Two new series of miniature surface mount two-terminal Gas Discharge Tubes (GDTs) from Littelfuse are designed to protect sensitive electronics from low to medium level lightning- induced surges and other voltage transients. The 3.5mm diameter size of the CG6 Series Miniature SMT GDT makes it the world’s smallest two- electrode single chamber GDT available on the market. It is also the first SMT GDT with two square terminals that offers 3kA (8/20μs), surge withstand capability (10 shots). The CG7 Series provides surge handling capability up to 1kA at 8/20μs (10 shots) in a miniature SMT footprint with one square terminal. Both series provide rapid response to fast-rising transients and have ultra low capacitance, which helps to minimize insertion and return losses to ensure signal integrity in high speed applications.

Applications for the CG6 and CG7 Series include broadband equipment, satellite and CATV equipment, dataline and Ethernet (up to 10bE) equipment, ADSL equipment, xDSL equipment, general telecom equipment, modems, Embedded Multimedia Terminal Adapters (EMTAs), set-top boxes, RF connectors, Multimedia over Coax Alliance (MoCA) equipment, base station RF antenna transmitters, and IADs (Internet Access Devices).


  • Low to medium surge capability – CG6: 3kA (8/20μs)
    - CG7: 1kA (8/20μs)
  • Ultra low capacitance (<0.3pF)
  • Surface mount form factor with square terminals
    - CG6: two squared terminals – CG7: one squared terminal
  • Minimal footprint
    - CG6: 3.5 x 3.5 x 4.0mm – CG7: 2.8 x 3.5mm


  • G.Fast modems
  • IAD
  • RF connectors
  • Broadband equipment
  • Satellite and CATV equipment
  • MoCA
  • EMTA
  • Set-top boxes


  • Allows greater design flexibility by offering two new GDT options for applications with surge protection requirements up to 3kA
  • Minimizes insertion losses to ensure signal integrity; ideal for high speed broadband applications
  • Aligns with the trend toward SMT in compact, space-limited applications; square terminals help improve manufacturing efficiency during PCB assembly process
  • Occupies less board space