A 4-bit 7.5 GHz A/D Converter

Abstract — Based on a conventional flash architecture a 4-bit GaAs analog to digital (A/D) converter has been designed using OMMIC-Philips GaAs foundry and particularly its commercial enhancement/depletion mode 0.18 µm pHEMT technology process. The ADC operates at 7.5 GHz sampling rate with full power analog input bandwidth from DC to Nyquist frequency. Differential source coupled FET logic (SCFL) was used and the complexity of the whole chip is more than 1900 active devices. The converter can be used in radar and software radio applications where there is requirement for high sampling rates in order the superheterodyne architecture for the down conversion to be avoided. I