A low-voltage wideband Voltage-Controlled Oscillator for ISDB-T

A 1.2 V, 1.7 ~ 3.4 GHz wideband Voltage-Controlled Oscillator (VCO) is proposed. To achieve the low voltage operation and wideband frequency tuning characteristic, 6-bit digitally controlled switched-capacitors bank and tunable bias circuit for four varactors are used. Total tuning range is as wide as 1.6 GHz and the VCO gain (Kvco) varies from 20 MHz/V to 180 MHz/V and the measured phase noise is -102 dBc/Hz at an offset frequency of 100 kHz from a 1.8 GHz operating frequency. The VCO chip implemented using a 90 nm CMOS process has size of 420 um × 570 um and consumes 2.4 mW.