Low voltage charge-pump-based Sigma-Delta Modulator using CMOS inverters as building blocks

The paper summarizes a concept of CMOS implementation of a new asynchronous sigma-delta modulator, based exclusively on CMOS inverters (or similar two-transistor blocks) as building blocks. The proposed a SigmaDelta-modulator is extremely suitable for low voltage operation and is fully compatible with digital CMOS, since there are only two transistors stacked in between supply rails. Circuit diagrams of particular functional blocks are presented. Selected simulation results with BSIM3v3 models provided by foundries are reported.