Flash analog-to-digital converter using resonant-tunneling multiple-valued circuits

• Published in: Proceedings / International Symposium on Multiple-Valued Logic pp. 94 - 99
• Main Authors: Waho, T., Hattori, K., Takamatsu, Y.
• Format: Conference Proceeding Journal Article
• Language: English
• Published: IEEE 2001
• Subjects: Analog-digital conversion; Circuit simulation; Diodes; FETs; Heterojunctions; Logic circuits; Multivalued logic; Resonant tunneling devices; RLC circuits; SPICE
• ISBN: 9780769510835; 0769510833
• ISSN: 0195-623X; 2378-2226
• DOI: 10.1109/ISMVL.2001.924560

We have proposed a flash analog-to-digital converter (ADC) that uses resonant-tunneling complex gates not only as ternary quantizers but also as ternary-to-binary encoder circuits. The ternary quantizers, consisting of monostable-to-multistable transition logic (MML) circuits, convert the analog input signal into the ternary thermometer code. This code is then converted into the binary Gray-code output by a multiple-valued, multiple-input monostable-to-bistable transition logic element (M/sup 2/-MOBILE). By assuming InP-based resonant-tunneling diodes and heterojunction field-effect transistors, we have carried out SPICE simulation that demonstrates ultrahigh-speed ADC operation at a clock frequency of 5 GHz. Compact circuit configuration, which is due to the combination of MML and M/sup 2/-MOBILE, reduces the device count and power dissipation by a factor of two compared with previous RTD-based ADCs.