Optimal Low Power Complex Filters

Realizations of voltage-mode and current-mode complex filters based on transconductance, transresistance, and current amplifiers for intermediate frequency (IF) applications are systematically developed. Various amplifiers are realized utilizing the second generation current conveyor (CCII) to promote comparisons at device levels. The adopted approach shows that the most efficient designs in terms of the number of active components are current-mode filters based on the transconductance and current amplifiers. As an application example, a 4th-order complex filter based on the CA is designed for low-IF Bluetooth receiver. Fabricated in a standard 0.18 μm CMOS technology, experimental results show that the proposed design offers improved characteristics over the available solutions in terms of power consumption and spurious-free dynamic range (SFDR). The filter exhibits in-band SFDR of 65.8 dB while consuming 1 mW.