A SiGe 6 modulus prescaler for a 60 GHz frequency synthesizer

Abstract

A prescaler is widely used in frequency synthesizers in order to handle channel selection. The division ratio has to be chosen carefully to achieve the desired frequency. In this paper, we present a 6 modulus prescaler in a 0.18 pm SiGe BiCMOS technology. The prescaler is part of a 60 GHz frequency synthesizer. In addition, we present a frequency planning for the 60 GHz frequency synthesizer. The prescaler employs an integer-TV architecture. The circuit has a programmable divider with a division ratio of 7 and 8 and two counters to control the division ratio. The programmable divider utilizes ECL circuits, while the counters utilise CMOS circuits. Therefore an ECL-to-CMOS converter is used to bridge these two kinds of circuits. Simulation results show that the prescaler operates up to 4 GHz from a 1.8 V supply voltage.