A 1V 1.7mW 25GHz transformer-feedback divide-by-3 frequency divider with quadrature outputs

A transformer-feedback injection-locked divide-by-3 frequency divider (ILFD) is proposed. Employing a transformer feedback, the divider can achieve high performance in terms of low voltage, high frequency, and low power consumption. Fabricated in a 0.13-mum CMOS process and operated at a 1-V supply voltage, the divider prototype measures an input frequency range from 22.7 GHz to 25.1 GHz with 2^nd and 3^rd harmonic tones of -45 dBc and -40 dBc respectively. With quadrature outputs, the divider achieves a sideband rejection ratio of 40 dB while consuming 1.7 mW and occupying an active area of 0.23 mm².