A low power low phase noise fractional-N synthesizer with linearization and mismatch noise shaping techniques for sub-GHz multi-band transceiver with narrow channel spacing

A fractional-N frequency synthesizer with a linearized phase-frequency detector and noise shaping of phase mismatch is presented. These techniques lead to spurious free operation over a wide frequency range (133-960M), and 15dB close in phase noise improvement. The core PLL consumes 15mW in 180nm CMOS and provides phase noise better than -94dBc/Hz@1kHz from a 924MHz carrier.