Low Power Current Conveyor Based Continuous Time Sigma Delta Modulator

A current-mode continuous-time sigma-delta modulator based on proposed low-power currentconveyor blocks is presented in this article. This modulator is designed for sensors which provide current output and convert directly the current-mode signal to digital code. An arbitrary feedback coefficients topology is chosen for providing an improvement in noise transfer function order, while a non-return to zero digital-to-analog converter (DAC) is utilized for reducing clock jitter sensitivity. In addition, noise and non-idealities analysis is considered to improve the circuit performance. The post-layout extraction simulation results confirm dynamic range of 89 dB for a bandwidth of 20 KHz with a power dissipation of 330 μW at a 1 V supply. The modulator design and worst case analysis are simulated in 90 nm CMOS standard TSMC technology.