CMOS PLL-Based Frequency Synthesizers for Broadband Wireless Communication System

In the modern communication system, frequency synthesizers play an essentialole either in the transmitting path or receiving path. Among several types ofrequency synthesizers, the PLL-based frequency synthesizers are the most popularne. However, conventional integer-N frequency synthesizers suffer from the tradeoffetween the loop bandwidth and the frequency resolution. Therefore, fractional-Nrequency synthesizers are adopted to achieve both small frequency resolution andide loop bandwidth.Σ fractional-N frequency synthesizers, for its lower spurs magnitude andigh-pass noise shaping ability, are most often adopted. Two ΔΣ fractional-Nrequency synthesizers implemented in TSMC 0.18-um process are presented in thishesis. Operating at 2.4 GHz, with the LC-VCO, the synthesizers exhibit good phaseoise.n appendix A, a low-power CMOS frequency synthesizer for mode-I (3432,960 and 4488 MHz) UWB MB-OFDM transceiver is presented. Implemented inMC 90 nm process, the synthesizer exhibits good phase noise and fast switchingime in 2 ns.n appendix B, a set of digital cells is established under TSMC 0.18-um process.tilizing the digital cells, the layout work of a digital circuit can be auto-routed by theid of some CAD tools.