A cost-effective multi-band LC oscillator for low-IF FM radio receivers

A cost-effective LC oscillator for a low-IF FM radio receiver has been realized. The FM radio receiver is fully integrated, except for two PCB-coils of the oscillator resonator. These coils enable easy adaption of the center frequency for various FM applications, for example for the Japanese FM band. The oscillator runs at twice the FM radio frequency band and covers a range of 158 MHz to 232 MHz, which is more than 38% tuning range. The phase noise to carrier ratio L(10kHz) is better than -101 dBc/Hz after division of the oscillator frequency by two. The LC resonator consists of 2 × 10 integrated band-switches, two integrated continuous varactors, and a combination of off-chip printed PCB-coils and bond-wire inductances. The composite balanced inductor has reduced overall spread compared to a bond-wire-only solution. An 11 GHz fTBiCMOS process is used for implementation, and the oscillator dissipates less than 6.1 mW with a supply voltage of 2.7 V.