Study On Fully-integrated Current-mode Continuous-time Filter Based On OTA-C And Its Layout

Continuous-time filter needn't A/D switch, data processing, D/A switch technique and so on to finish filtering function with analog signal like digital filter. And it needn't switch action to sample data in the discrete time with analog signal like switched capacitor filter. So continuous-time filter has several advantages, such as high processing speed, simple circuit configuration, and low power consumption. Continuous-time analog filter is the only method when processing high frequency signal (usually above 1MHz) in low power consumption. It has been widely used in the area of communication, electronic measurement, instruments, autocontrol, etc. It's especially used in digital and analog mixed signal processing and communication integrated circuit.Current-mode filter becomes the new research direction in the world, as it's high speed, low power consumption and simple configuration. Current-mode continuous-time filter is current-mode circuit, so it has characteristics of current-mode circuit. Typical current-mode continuous-time filters include current-mode filter based on current conveyor, current-mode filter based on OTA-C and current-mode filter based on current mirrors. They are rapidly developed in bandwidth, speed, precision, etc, and they bring the filter theories to noble times of fully integrated system development.There are many articles on continuous-time filter based on OTA in nearly two years. Filter based on OTA-C needn't resistors, and the transconductance value of CMOS-OTA is relatively low. Using small capacitor can obtain large gm/C value, so it's suitable for integrated chip. Moreover, the filter parameters, such asω0, Q and so on can be controlled by exterior adjusting or programming, because OTA is...