DESIGN OF A 3 GHz 6TH ORDER DELTA-SIGMA MODULATOR IN A 0.2 μm GaAs TECHNOLOGY

International audienceThis paper presents the design of a monobit 6th order delta-sigma modulator in a GaAs 0.2 μm technology. The central frequency is 750 MHz and the sampling frequency is 3 GHz. The reached resolution is 10.5 bits over a 10 MHz bandwith. The modulator operates from ± 5 V power supplies and consumes 5.7 W. Each block of the modulator is presented at transistor level. Two drawbacks are pointed out: low pass terms of Gm-LC resonators and the lowpass characteristic of the adder. Two solutions are proposed. Finally, simulation results of the complete modulator are given