GHz Class Low-Power Flash ADC for Broadband Communications

A low-power (~400 mW) high-speed (2-4 GS/s) 4-bit analogue-to-digital converter (ADC) based on InP/InGaAs heterojunction bipolar transistors (HBT) has been designed and simulated. The technology utilised two novel developments. Firstly stoichiometric conditions permitted growth at a relatively low temperature (420degC) while conserving extremely high-quality materials. Secondly dimeric phosphorus generated from a gallium phosphide (GaP) decomposition source has lead to excellent device properties. The complete ADC shows state-of-the-art performance and includes an interface for connection to standard digital signal processing (DSP) systems whilst dissipating only 400 mW.