A 3rd-Order 235MHz Low-Pass gmC-Filter in 120nm CMOS

A 3rd-order continuous-time filter with a cut-off frequency of 235MHz in 120nm CMOS is presented. A linearization technique of an operational transconductance amplifier (OTA) is proposed. The gain of this filter is digitally programmable between 0.5dB and -5dB. The third-harmonic distortion of this filter is -49dB in maximum gain for a 400mV peak-to-peak differential output signal. Two identical filters were implemented on one chip to measure the mismatch which is lower than 0.7 dB in amplitude and 7deg in phase

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