Analog Devices,inc.

Andrew Abo

Robert W Adams

Colin Gerard Lyden

Paschal Thomas Minogue

Atsushi Matamura

Maria Del Mar Chamarro Marti

Paul John Morrow

Mike Dominic Keane

Richard Thomas O'Brien

Hans Johan Olaf Mansson

A sigma-delta digital-to-analog converter comprises a current digital-to-analog converter (IDAC) stage which generates a current depending on an input digital signal. An output current-to-voltage converter converts the generated signal to a voltage on a continuous-time basis. The amplifier used in the output current-to-voltage converter is chopper-stabilized. The converter can be single bit or multi-bit. The IDAC stage can be implemented with a pair of branches, a first branch comprising a first biasing current source and a second branch comprising a second biasing current source. The biasing current sources can be chopper-stabilized by connecting the bias current sources to the output current-to-voltage converter by a set of switches. The switches connect the biasing current sources to the output current-to-voltage converter in a first configuration and a second, reversed, configuration. This modulates flicker noise contributed by the bias current sources to the chopping frequency. from where it can be removed by filtering downstream of the current-to-voltage converter.

Continuous-time-sigma-delta DAC using chopper stabalization

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Can Jose, CA, United States of America

Andrew Abo