A 900-MHz fully integrated LC-VCO for ISM applications

In this paper, a fully integrated LC-VCO for FSWASK applications in the 868-MHz and 915-MHz ISM bands is presented. The VCO was realized in a 0.5-pm BiCMOS process with a power metal layer and integrated varactor diodes. For the VCO design, the focus was on simplicity, good bias noise suppression, and a wide supply voltage range. The achieved phase noise level is -99 dBcMz at an offset frequency af 1QQ kHz. The circuit consumes only 1.35 mA from a supply voltage between 1.9 V and 5.5 V. The VCO is controlled with AC-coupled integrated varactor diodes and achieves a tuning range of 160 MHz at a nominal supply voltage of 3 V.