Transconductance Mode CMOS Synchronous Rectifier Circuits

Two CMOS synchronous rectifiers have been implemented using 0.13 mu m technology. Together, the two designs can rectify a 2.4 GHz RF input signal over a 40 dB dynamic range from -30 dBm to + 10 dBm. The CMOS rectifiers are designed to operate either as class-B or class-C synchronous rectifiers. In one design, a zero-threshold voltage device is shunted by a positive threshold device to provide rectification at very low RF input power levels. At low power, the zero-threshold device operates in the class-B mode, and once the RF input power is large enough, the second device starts to rectify in the class-C mode. A second design operates entirely in the class-C mode and provides good rectification for RF power levels above 0 dBm.