Ultra-Low-Voltage 20-GHz Frequency Dividers Using Transformer Feedback in 0.18-$mu$ m CMOS Process

This paper presents the design and analysis of ultra- low-voltage (ULV) high-frequency dividers using transformer feedback. Specifically, a differential-input differential-output injection-locked (IL) divider topology with transformer feedback and a wideband transformer-coupled (TC) divider with quadrature outputs are demonstrated, both of which can operate well at supply voltages as low as the device's threshold voltages. Fabricated in a standard 0.18-mum CMOS process, the ULV-IL divider measures an input frequency range from 16.1 GHz to 20 GHz while consuming a total power from 2.75 mW to 4.35 mW at 0.5 V supply, and the TC-divider measures an input frequency range of 27.8% from 15.1 GHz to 20 GHz with IQ sideband rejection of - 31 dBc while consuming power from 11.4 mW to 13.6 mW at 0.6 V supply.