A 4 GHz BiCMOS frequency synthesizer

Describes the first in a range of frequency synthesizer products being designed by Analog Devices in Limerick. The device is part of a family of parts at various power levels targeted at the frequency range 500 MHz to 3.5 GHz. First silicon has been evaluated and shows correct operation to 4 GHz for the highest power version, consuming 1O mA approximately. The process used is 0.6 μm BiCMOS with 20 GHz F_T NPN transistors and 0.6 μm CMOS, running in the Limerick Fab. It is planned to follow up with a dual RF/IF part, a fractional-N part and parts with a self-contained VCO