1-V 365- 2.5-MHz Channel Selection Filter for 3G Wireless Receiver in 55-nm CMOS

This paper presents a novel 1-V 2.5-MHz continuous-time filter for 3G wireless application, fabricated using a standard 55-nm CMOS process. The four-pole filter topology includes a single pole-tracking Operational Amplifier (OPAMP) structure to achieve low in-band noise levels, high out-of-band linearity, and reduced power consumption. An automatic frequency tuning circuit is developed to compensate for process and environmental variations. The proposed filter achieves inband noise of 18-μV rms and out-of-band IIP3 of 33 dBm within 365 μW. The out-of-band spurious-free dynamic range is measured at 76.7 dB, resulting in a figure-of-merit of 1.24 × 10^-4 fJ.