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