초록 ▼

A variable attenuator having first and second branch circuits configured in bridged T, T or PI topologies, each of the branch circuits having at least one voltage variable FET resistor. The voltage variable FET resistor includes a FET network comprising a plurality of FET segments each of which have

A variable attenuator having first and second branch circuits configured in bridged T, T or PI topologies, each of the branch circuits having at least one voltage variable FET resistor. The voltage variable FET resistor includes a FET network comprising a plurality of FET segments each of which have a predetermined gate width and a voltage divider network including a plurality of fixed resistors coupled to the gates of the plurality of FET segments for providing a different predetermined gate voltage to each of the FET segments. The gate width of each of the FET segments and the resistance of each of the fixed resistors is chosen to provide a predetermined relationship between the control voltage and the channel resistance of the voltage variable FET resistor, to thereby provide a preselected relationship between the control voltage applied to the first branch circuit and the attenuation ratio of the attenuator.

대표청구항 ▼

A variable attenuator comprising: (a) a first branch circuit coupled to a source terminal and a load terminal, said first branch circuit including at least one voltage variable FET resistor having output and input terminals and a control voltage terminal; (b) a second branch circuit coupled to said

A variable attenuator comprising: (a) a first branch circuit coupled to a source terminal and a load terminal, said first branch circuit including at least one voltage variable FET resistor having output and input terminals and a control voltage terminal; (b) a second branch circuit coupled to said first branch circuit and a common terminal, said second branch circuit including at least one voltage variable FET resistor having input and output terminals and a control voltage terminal; (c) each of said voltage variable FET resistors comprising: (i) a FET network including a plurality of FET segments having source, drain and gate electrodes, the drain electrodes of each of the plurality of FET segments being coupled to said output terminal, the source electrodes of each of the plurality of FET segments being coupled to said input terminal, and the gate electrodes of each of the plurality of FET segments being coupled to said control voltage terminal, each of said plurality of FET segments having a predetermined gate width; and (ii) a voltage divider network coupled to said gate electrodes of said plurality of FET segments for providing a different predetermined gate voltage to each of said gate electrodes.