Reconfigurable hybrid CT/DT delta-sigma modulator with op-amp sharing technique dedicated to multi mode receivers

A novel multi mode low pass hybrid continuous/discrete time delta sigma modulator which is suitable for low power wide band applications is presented in this article. The proposed topology can adapt itself for operating in various signal bandwidths as well as different signal to noise plus distortion ratios (SNDRs). The novelty of the proposed modulator lies in the fact that several techniques have been employed simultaneously that not only can reduce the power consumption, but also it can increase the performance of the modulator. Continuous time integrator is utilized to alleviate the specs for the first stage op-amp. The modulator employs an op-amp sharing technique, which decreases the power consumption dramatically due to elimination of the power hungry adder before the quantizer in the feed forward topology. Another attractive advantage of the proposed modulator is using the noise-shaping enhancement technique which can increase the performance of the modulator without using analog active blocks. The unused block of the modulator can be made inactive to achieve less power dissipation. Behavioral simulations in MATLAB environment show the SNDR of 91/86/73 dB over 0.2/2/20 MHz signal bandwidth.