A finite gain bandwidth compensation method for low power continuous-time ΣΔ modulator

Finite gain-bandwidth (GBW) effects include gain-error (GE) and loop delay which would degrade the overall performance of continuous-time ΣΔ modulator (CTDSM). This paper introduces an easy and simple finite GBW compensation method for CTDSM with active-RC integrators. This method overweighs other compensation methods by compensating GE and loop delay respectively, which can ensure the accuracy better. Moreover, this method is simple and easy while other methods need CT-to-DT conversion which makes it complex. With this compensation method applied, lower GBW amplifiers can be used to achieve lower power dissipation. A third-order CTDSM with 10MHz bandwidth, 400MHz sampling rate was simulated to verify the effectiveness of the method.