A 28.5–32-GHz Fast Settling Multichannel PLL Synthesizer for 60-GHz WPAN Radio

A 28.5-32-GHz fast settling multichannel frequency synthesizer is implemented in 0.25-mum SiGe : C BiCMOS process technology for 60-GHz wireless personal area network (WPAN) applications. The phase-locked loop (PLL) synthesizes carrier frequencies between 28.5-32 GHz in step of 500 MHz, and settles in approximately 327 ns. The proposed PLL can be employed as a frequency source providing eight channels of frequency hopping carriers for 60-GHz WPAN radio. To generate eight channels of carriers, an integer-N PLL with 125-MHz reference frequency is implemented, and a programmable divider with all differential current-steering circuits is designed. The programmable divider reliably provides divide ratios of 114-128 at 15 GHz. To achieve eight channels of carriers at a challenging frequency of 30 GHz, a push-push voltage-controlled oscillator is employed using a Wilkinson power combiner. The PLL consumes 115 mA at 2.5 V and achieves phase noise of -81 dBc/Hz at 1-MHz offset measured from 32-GHz push-push carrier.