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SMB (SubMiniature version B) connectors are coaxial RF connectors developed in the 1960s. SMB connectors are smaller than SMA connectors.
They feature a snap-on coupling and are available in either 50 Ω or 75 Ω impedance. They offer excellent electrical performance from DC to 4 GHz.

An SMB jack has a male center pin, while an SMB plug has a female basket.


Electrical DataDetail
Impedance50 ohms
Frequency range0 to 4GHz
Working Voltage
  • RG178=250Vrms at sea level max.
  • RG174,316=335 Vrms at sea level max.
Dielectric withstanding voltage
  • RG178=750 Volts rms min.
  • RG174,316=1000 Volts rms min.
  • Straight connector :
  • RG178=1.30+0.04F(F in GHz)
  • RG174,316=1.25+0.04F(F in GHz)
  • R/A connector:
  • RG178=1.45+0.06F(F in GHz)
  • RG174,316=1.35+0.04F(F in GHz)


Mechanical DataDetail
Engagement force14.0 pounds max.
Disengagement force2 lbs~14.0 lbs
Connector durablity500 matings
Cable retention force
  • RG178=7.3 lbs min.
  • RG174=9.7 lbs min.
  • RG316=12.1 lbs min.