A frequency hopping synthesizer IC for IF and RF applications

This paper describes an integrated circuit containing all building blocks of a complete PLL based synthesizer except for the loop-filter and the VCO. The circuit was designed to fit into existing applications ranging from IF to RF in a modem cellular base station. The circuit includes structures to automatically modify the properties of the phase detector and the loop filter to facilitate frequency hopping. Some other interesting circuit structures are the 200 MHz reference divider producing output signal with a 50% duty -cycle, the low-noise (-148 dBc/√(Hz)) 4-bit digital-to-current converters embedded into the 80 MHz dual-mode phase-frequency detector and the multi-mode prescaler that operates up to 2 GHz. The circuit, which is 2.6 mm×2.1 mm in size and consumes 80 mA from a 5 V supply, is processed in a 12 GHz 0.8 μm BiCMOS process