A High-Power and Highly Linear CMOS Switched Capacitor

A new CMOS switched capacitor is developed to be used for high-power applications such as a power amplifier, where high voltage handling capability and low distortion are two major factors. In order to demonstrate superior performance of the proposed structure over a conventional structure, two designs are analyzed and compared while maintaining comparable small signal characteristics such as a 2:1 tuning ratio and a quality factor. The maximum applicable voltage swing of the proposed structure is improved over the conventional structure by a factor of V_DD / V_th, or 12 dB in this design. The proposed structure also shows a greatly improved two-tone third-order inter-modulation distortion characteristic with a maximum 34 dB improvement. This proposed structure is a suitable component for tunable CMOS power amplifier applications.