Title :
A transistor-only switched current sigma-delta A/D converter for a CMOS speech CODEC
Author :
Nedved, Jiri ; Vanneuville, Jozef ; Gevaert, Dorine ; Sevenhans, Jan
Author_Institution :
Dept. of Microelectron., Czech Tech. Univ., Prague, Czech Republic
fDate :
7/1/1995 12:00:00 AM
Abstract :
This paper describes the design and measurement results of a 1-b A/D converter based on a transistor-only switched current (SI) second-order sigma-delta modulator. The 1-b A/D converter was simulated and processed in ES2 1.5 μm CMOS technology. The second-order filter is based on class AB switched current-integrators. The analog current memory cells in the integrator are optimized for linear operation with a strong class AB overlap region to avoid class B operation and cross-over distortion. Measurement results on the first silicon performing 11-b resolution show that this circuit technique is promising for speech CODEC A/D conversion
Keywords :
CMOS digital integrated circuits; integrating circuits; sigma-delta modulation; speech codecs; switched current circuits; 1.5 micron; 11 bit; CMOS speech CODEC; ES2 CMOS technology; analog current memory cells; class AB overlap region; class AB switched current-integrators; cross-over distortion; linear operation; second-order filter; sigma-delta A/D converter; switched current circuits; CMOS process; CMOS technology; Current measurement; Delta-sigma modulation; Distortion measurement; Filters; Integrated circuit measurements; Performance evaluation; Silicon; Switching converters;
Journal_Title :
Solid-State Circuits, IEEE Journal of
