A 600MHz CMOS OFDM LINC transmitter with a 7 bit digital phase modulator

This paper presents a new architecture for a LINC transmitter adopting a digital phase modulator (DPM). The DPM uses a 7 bit digital input to directly modulate the RF phase of each path, thus simplifying gain/phase mismatch compensation. Furthermore, this feature needs only one set of test signals for gain and phase mismatch detection. The implemented LINC transmitter IC consumes 140mA from a 1.9V supply including an LC quadrature VCO, two DPMs, and two PA driver amplifiers, and it transmits a 6MHz bandwidth 64-QAM OFDM signal in the UHF TV band with external switching PAs and a power combiner.