A transmitter CMOS VCO for WCDMA/EDGE

A VCO is implemented in an RF 90nm CMOS process and covers the frequency range 2.55-4.08GHz. Drawing 19mA from 1.2V, the phase noise at 20MHz frequency offset from a 3.7GHz carrier is -156dBc/Hz, meeting the phase noise requirement for GSM. A second version of the VCO covers an additional 4.90-5.75GHz range, at the expense of a higher phase noise in the added band. In this way, all WCDMA/EDGE bands can be synthesized by a single VCO.