LC-TANK INJECTION-LOCKED FREQUENCY DIVIDER WITH VARIABLE DIVISION RATIO

In this study, a multimodulus CMOS injection-locked frequency divider (ILFD) fabricated in a 0.18-mu m CMOS process is designed and the operation principle of the ILFD is described, which was realized using a cross-coupled PMOS LC-tank oscillator as the load of a double-balanced NMOS Gilbert mixer. The stacked structure allows entire mixer current to be reused by the VCO cross-coupled pair. At the supply voltage of 1.8 V, the free-running frequency is from 2.31 to 2.65 GHz. Division ratio of 2, 3, 4, and 6 can be found in the ILFD function, and the ILFD can also function as a first-harmonic injection-locked oscillator. At the incident power of 0 dBm, the locking range in the divided by 2 mode is from the incident frequency 3.4 to 6.4 GHz. (c) 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3232-3236, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23928