A Fully Integrated 1.3GHz VCO for GSM in 0.25μm Standard CMOS with a Phasenoise of -- 142dBc/Hz at 3MHz Offset

A fully integrated voltage controlled oscillator for a 900MHz GSM heterodyne receiver with an IF at 400MHz is presented. The LC-VCO was designed in INFINEON low-cost 0.25μm 4 metal standard CMOS process, using an integrated fully symmetrical coil. The VCO consumes 7mA at a 2V supply voltage (14mW) and features a measured phasenoise of -- 142dBc/Hz at 3MHz offset or -- 112dBc/Hz at 100kHz, thus fulfilling GSM receive requirements. A very linear tuning characteristic of 200MHz is obtained through backgate-tuning of NMOS-varactors.