Digitally controlled 3GHz 360° phase modulator in an 1.2V 65nm CMOS technology

This paper presents a phase modulator topology suitable for frequencies up to 3 GHz. The proposed phase modulator offers digital phase modulation for digital centric polar transmitter frontends as used e.g. in software defined radios. The achievable phase resolution is 11.2° which equals 10.4 ps at 3 GHz. The phase modulation is based on an delay lock loop (DLL), from which signals with different delays are forwarded by a multiplexer.