A CMOS quality factor enhanced parallel resonant LC-tank with independent Q and frequency tuning for RF integrated filters

Abstract

A new quality factor enhanced resonator core is presented and used to design a bandpass filter at 2.4GHz. The new Q-enhanced LC-tank has independent Q tuning capability, which substantially simplifies the automatic Q-tuning problem. In simulation, the unloaded Q-enhanced core consumes 7.05mA from a 1.8V supply in 0.18/spl mu/m CMOS and can be tuned from 2.1GHz to 3.5GHz using varactors. A brief discussion of the proposed automatic Q-tuning system is presented. The synthesized 2.45GHz filter has a bandwidth of 148MHz, 0dB insertion loss over a 10% tuning range, and a 1/sup st/ order compression point of -0.5dBm at 2.35GHz.