Analog-to-digital converter based on RSFQ technology for radio astronomy applications

We are developing an analog-to-digital converter (ADC) based on rapid single-flux quantum technology for radio-astronomic spectroscopy applications where very wide bandwidth is required and relatively small resolution is sufficient. The ADC consists of periodic-flash comparators, a demultiplexer and output drivers; and is sufficiently simple to be implemented on a single chip using a conventional 2–3 μm Nb trilayer technology. A 2-bit ADC has been designed for operation at 16 GHz of the sampling frequency. All the subsystems of the ADC have been fabricated using standard 1.6 kA cm −2 Nb/AlO x /Nb technology and have been successfully tested.