A High-Speed HBT Prescaler Based on the Divide-by-Two Topology

This paper demonstrates the Divide-by-4/5 prescalers with merged AND gates in 2 mum GalnP/GaAs heterojunction bipolar transistor (HBT) and 0.35 mum SiGe HBT technologies. By biasing the HBT near the peak transit-time frequency (fr), the maximum operating frequency of a D-type flip-flop (D-FF) can be promoted. At the supply voltage of 5 V, the GalnP/GaAs prescaler operates from 30 MHz to 5.2 GHz, and the SiGe prescaler has the higher-speed performance of 1 GHz ~ 8 GHz at the cost of power consumption.