A low noise vector modulator with integrated basebandfilter in 120 nm CMOS technology

A low noise vector modulator for cellular systems with integrated baseband filter has been developed in 120 nm CMOS technology. The baseband filter is an anti-aliasing filter for the digital to analogue converter of the baseband that has been build around a differential amplifier with 3/sup rd/ order butterworth low pass characteristic. High linearity and low output noise can be achieved for the modulator due to the current interface between the baseband filter and the mixer cells. The GSM specification for emitted noise into the receive band can be fulfilled without using a duplex filter behind the power amplifier output.