A 5/sup th/-order continuous-time harmonic-rejection G/sub m/C filter with in-situ calibration for use in transmitter applications

A 0.18 /spl mu/m CMOS fifth-order harmonic-rejection G/sub m/C filter is presented for use in offset PLL transmitter applications. Using an in-situ calibration scheme with a tuning accuracy of 2% and a maximum calibration time of 90 /spl mu/s, this filter tunes from 52 to 151MHz and draws 7mA from a 1.8V supply while achieving an IIP3 of 7dBV with an output noise floor of 9.3 /spl mu/V in a 30kHz BW.