Cellular multicarrier transmitters for communication infrastructure require both high linearity and large bandwidth (BW) at GHz frequencies. The combination of multicarrier GSM, WCDMA and LTE typically requires IMD<;-80dBc and SFDR>80dBc in a large transmit bandwidth of 300MHz and at an output frequency of up to 3.5GHz and beyond. Current-Steering (CS) Nyquist DACs have large BW, but their linearity drops for increasing output frequencies [1]. A separate mixer is therefore needed to generate an RF signal with high linearity. A Mixing-DAC integrates the function of the mixer and DAC together. Using a Mixing-DAC can result in different architecture trade-offs which potentially enable a reduction of the cost and power consumption, while improving the linearity at high frequencies. The state-of-the-art Mixing-DACs attain linearity by means of A2 modulation [2,3] or low sample rate [4], but this results in a limited BW and does not result in a linearity better than IMD=-71dBc. Even a GaAs implementation [5] only achieves IMD=-70dBc while consuming 1.2W.
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