Title :
Design of SFQ-counting analog-to-digital converter
Author :
Lin, J.C. ; Semenov, V.K. ; Likharev, K.K.
Author_Institution :
Dept. of Electr. Eng., State Univ. of New York, Stony Brook, NY, USA
fDate :
6/1/1995 12:00:00 AM
Abstract :
We describe the design of an oversampling single-flux-counting analog-to-digital converter with the estimated bandwidth of a few tens of MHz, based on Rapid Single-Flux-Quantum (RSFQ) devices. It consists of an input analog circuit, high-speed quantizer with an original analog/digital negative feedback loop, decimation (comb) filter, and supporting subsystems including clock distribution circuits, quantization signal conditioner, and output drivers. We have applied a new approach, the ´symmetrizing´ negative feedback, to free the quantizer from the intrinsic hysteresis without dynamic range sacrifice. The 16-bit version of the system comprises about 1,500 Josephson junctions and consumes 1.2 mW of DC power, when implemented using Nb-trilayer technology with 1 kA/cm/sup 2/, 3.5 /spl mu/m Josephson junctions. All subsystems of the converter have been successfully tested and testing of the system as a whole is in progress.<>
Keywords :
Josephson effect; analogue-digital conversion; circuit feedback; quantisation (signal); superconducting integrated circuits; 1.2 mW; 16 bit; 3.5 micron; Josephson junctions; Nb; Nb-trilayer technology; RSFQ devices; SFQ-counting ADC; analog-to-digital converter; analog/digital negative feedback loop; clock distribution circuits; comb filter; decimation filter; high-speed quantizer; output drivers; oversampling ADC; quantization signal conditioner; rapid single-flux-quantum devices; single-flux-counting type; symmetrizing negative feedback; Analog circuits; Analog-digital conversion; Bandwidth; Clocks; Digital filters; Feedback circuits; Josephson junctions; Negative feedback loops; Quantization; System testing;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
