A programmable coefficient continuous-time A/D Δ-Σ modulator

Author

Allen, Daniel J. ; Pereira, Angelo W. ; Hasler, Paul

Author_Institution

Georgia Inst. of Technol., USA

Volume

1

fYear

2004

fDate

23-26 May 2004

Abstract

A continuous-time Δ-Σmodulator has been proposed that uses floating-gate transistors to program the feed-forward and feedback coefficients. The G_m-C integrators are designed to run in subthreshold and take advantage of the floating gate circuit architecture to increase the linear range and minimize V_TH error. A 2nd order modulator was fabricated in 0.5μm CMOS with measured maximum SNR of 59.2dB, maximum SINAD of 50.27 and a DR approximately 50dB. A modulator with an unlatched comparator was also tested and an initial investigation has begun into the asynchronous behaviour of the modulator when it is without clocking.

Keywords

CMOS integrated circuits; analogue-digital conversion; comparators (circuits); delta-sigma modulation; integrating circuits; modulators; programmable circuits; 0.5 micron; A/D Δ-Σ modulator; G_m-C integrators; continuous-time modulator; feed-forward coefficients; feedback coefficients; floating gate circuit architecture; floating-gate transistors; programmable coefficient modulator; unlatched comparator; Circuits; Clocks; Delta modulation; Equations; Modulation coding; Negative feedback; Output feedback; Parasitic capacitance; Switches; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2004. ISCAS '04. Proceedings of the 2004 International Symposium on

Print_ISBN

0-7803-8251-X

Type

conf

DOI

10.1109/ISCAS.2004.1328403

Filename

1328403