A Fast-Locking Agile Frequency Synthesizer for MIMO Dual-mode WiFi / WiMAX Applications

In this paper, a frequency synthesizer based on phase-locked loop (PLL) technique for dual-mode WiFi (2.4-GHz band) and WiMax (5-GHz band) applications is presented. The frequency synthesizer with wide frequency range application and the settling time within 10-mus is realized by a time-to-voltage converter (TVC). A 40-MHz input reference for 125-KHz frequency steps which is realized by a 12-bits MASH 1-1 delta-sigma modulator for fractional divisions. The frequency synthesizer provides output frequency ranges from 4.6-GHz to 5.4-GHz with simulated phase noise of around -110 dBc/Hz at 1-MHz offset. Simulated in standard 0.13-μm CMOS process, the frequency synthesizer dissipates 40-mW from a 1.2-V power supply.