A wideband CMOS LC VCO with low tuning sensitivity for CMMB applications

A dual core wideband voltage-controlled oscillator (VCO) with small VCO tuning gain fluctuation ( K
_VCO
variation ) is presented. This integrated VCO has a wide tuning range from 1.8 GHz to 3.8 GHz, which can provide all desired frequency band for China Mobile Multimedia Broadcasting (CMMB) receiver. A 5-bit switched capacitor bank and a self-controlled varactor pair is used in each core to achieve required tuning range and small tuning sensitivity. Spot phase noise is -119.5 dBc/Hz at 1 MHz offset for 3.817 GHz output frequency while power dissipation is 3-4 mA from 1.5 V supply. This circuit is realized in 0.18-¿m CMOS technology and the total area is 530 × 440 ¿m
²
.