5 Gsps Oversampling Analog-to-Digital Converters with Polarity Alternating Feedback Comparator

Takumi MIYASHITA  Alfredo OLMOS  Mizuhisa NIHEI  Yuu WATANABE  

IEICE TRANSACTIONS on Electronics   Vol.E82-C   No.3   pp.483-490
Publication Date: 1999/03/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Ultra-High-Speed IC and LSI Technology)
Category: Compound Semiconductor Devices
compound-semiconductor,  HEMT,  over-sampling,  data-converter,  A/D converter,  CDMA,  

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We fabricated and evaluated a second-order ΣΔ ADC with a polarity alternating feedback (PAF) comparator based on 0.4 µm InGaP/InGaAs enhancement and depletion mode high electron mobility transistors (E/D HEMT) technology. We propose a PAF technique for enhancing the sampling frequency and have applied the technique in the design of ADC circuit. The ADC has a signal-to-noise ratio (SNR) of 43 dB when operating at a differential clock frequency of 4.9 GHz, and has a power dissipation of 400 mW.