2–6GHz current-reused LNA with transformer-type inductors

In this work, a wideband CMOS LNA utilizing current-reused cascode topology is proposed. One series inductor and one shunt capacitor is inserted between two DC cascoded transistors in order that two transistors work as two cascaded common-source amplifiers under RF signals. Hence, higher power gain should be obtained. In general, more inductors are used to fulfill wideband matching and the current-reused topology. In this research, we designed an original wideband current-reused LNA previously. From the designed circuit structure, it can be found that three couples of inductors which are similar to center-tapped transformers. Hence, supply-feeding and matching inductors are combined into center-tapped transformers in order to save chip area.