An 8-GHz continuous-time analog-digital converter in an InP-based HBT technology

tinuous-time – analog–digital converter (ADC) that achieves 57.4-, 51.7-, and 40.2-dB SNR at signal sampling rates of 125, 250, and 500 Ms/s, respectively. The integrated circuit occupied 1.45-mm2 die area, contains 76 transistors, is fabricated in an InP-based HBT technology, and dissipates 1.8 W. We also study the effect of excess delay on modulator performance, and show that excess delay does not affect performance as long as the centroid-in-time of the digital–analog converter pulse remains stationary. Index Terms—Analog-to-digital converter (ADC), continuous time, delta–sigma, HBTs, InP. I