A 57-dB image band rejection CMOS GmC polyphase filter with automatic frequency tuning for Bluetooth

In English A 7th order polyphase G/sub -m/C IF filter with automatic frequency tuning, implemented in a 0.35/spl mu/m CMOS process, is presented. The filter has a center frequency of 3MHz and a passband of 1MHz. The image band rejection is higher than 57dB, the stop band attenuation is at least 40dB. The in-band spurious free dynamic range is around 53dB. On-chip automatic frequency tuning provides more than 240% center frequency range (i.e., 1.6MHz-3.9MHz) of the filter. The filter is well suited for employment in the Bluetooth short-range radio.