Investigation of the High Frequency Operation of Gm-C Integrators for Continuous Time Filters

Factors governing the high-frequency behavior of Gm-C integrators are discussed. In sub-micron regime, speed of devices is suitable for high-frequency applications, but low output resistance results in reduction of Q-factor. Parasitic poles result in excess phase shift. These two opposing factors determine the phase error at unity-gain frequency. In this paper, while comparing some topologies we show that it is the process variation of the phase error, that limits the usable bandwidth of an integrator. Dependence of Q-factor on short-channel effects is also considered