An 18-GHz Continuous-Time – Analog–Digital Converter Implemented in InP-Transferred Substrate HBT Technology

Abstract—We report an 18-GHz clock-rate second-order con-tinuous-time – analog–digital converter (ADC) implemented using InP-transferred substrate HBTs. Under two-tone test condi-tions, the ADC achieved 43 dB and 33 dB SNR at signal frequencies of 500 MHz and 990 MHz, respectively. The IC occupied 1.95 mm2 die area and dissipated 1.5 W. Index Terms—ADC, delta–sigma, heterojunction bipolar tran-sistor, substrate transfer. I