A transformer-coupled LC-tank injection locked frequency divider

This article designs an injection locked frequency divider (ILFD) based on the direct injection technique and transformer-coupled VCO topology. At the supply voltage of 3.3 V, the timing range of the free-running ILFD is from 2.47 to 2.32 GHz, about 150 MHz, and the locking range of the ILFD is from 4.58 to 5.09 GHz, about 510 MHz at the injection signal power of 0 dBm. The ILFD dissipates 188 m W at 3.3 V supply voltage and was fabricated in the TSMC 0.35 mu m CMOS 2P4M CMOS technology. At the tuning voltage of 2.5 V, the measured phase noise of free-running ILFD is about -116 7 dBc/Hz at 1 MHz offset frequency from 2.4 GHz, and the phase noise of the locked ILFD is about -128.6 dBc/Hz, while the input signal is with a power of -4 dBm. (c) 2008 Wiley Periodicals, Inc.