A LOW-VOLTAGE SWITCHED-CURRENT DELTA-SIGMA MODULATOR

This paper presents the design of a fully differential switched-curren t delta-sigma modulator using a single 3.3-V power-supply voltage. At system level, we tailor the modulator structure considering the simila rity and difference of switched-capacitor and switched-current realiza tions. At circuit level, we propose a new switched-current memory cell and integrator with improved common mode feedback, without which low power-supply-voltage operation would not be possible, The whole modula tor was implemented in a 0.8-mu m double-metal digital CMOS process. I t occupies an active area of 0.53 x 0.48 mm(2) and consumes a current of 0.6 mA from a single 3.3-V power supply, The measured dynamic range is over 10 b.