A frequency synthesizer is one of the most critical building blocks in any integrated wireless transceiver system. Its design is getting more and more challenging as the demand for low-voltage low-power high-frequency wireless systems is continuously increased. At the same time, CMOS processes have advanced and been shown to be more and more attractive due to their potential in achieving systems with the highest integration level and the lowest cost. On the other hand, as the supply voltage is lowered, many existing design techniques for integrated frequency synthesizers are no longer applicable. However, it is still desirable to design RF frequency synthesizers at low supply voltages not only because of the device reliability due to the technology scaling but also because of the integration and compatibility with digital circuits.

There are currently only a few books available on integrated RFCMOS frequency synthesizers. The most comprehensive book on integrated CMOS frequency synthesizers available today is entitled Wireless CMOS Frequency Synthesizer Design by Craninckx and Steyaert (1998). More recently, another book entitled Multi-GHz Frequency Synthesis and Division by Rategh and Lee was also published in 2001. While the two books are still quite useful, they focus only on advanced design techniques of some selected building blocks, including voltage-controlled oscillators, dividers, and synthesizers, with emphasis only on a particular architecture. There exist many new synthesizer architectures and design techniques that are not covered in detail.