A novel resonant tunneling delta-sigma A/D converter having no feedback loop for ultrahigh-speed operation

A resonant tunneling logic gate MOBILE is an ultrahigh-speed functional logic gate which switches at the rising edge of the clock. In this paper we describe a novel Δσ ADC having no feedback loop which make the best use of high-frequency performance of the RTD. The Δσ modulator use to convert the analog signal to the pulse density digital signal. This modulation technique suitable to MOBILEs using VCO were employed here. Testing the Δσ modulator concept using the MOBILE fabricated on the InP substrate concludes that the MOBILE works as an ideal 1-bit quantizer for high-speed ADCs.