Performance Evaluation of Different Types of CMOS Operational Transconductance Amplifier

The OTA is a basic building blocks found in many analog circuits such as data converter�s (ADC& DAC) and Gm-C filters. Performance of Gm-C filters is related to the OTA�s performance. The OTA is a Transconductance device in which the input voltage controls the output current, it means that OTA is a voltage controlled current source whereas the op-amps are voltage controlled voltage source. An OTA is basically an op-amp without output buffer, so it can only drive loads. The paper represents the different types of CMOS OTA with its fundamentals. The different topology of CMOS OTA is also described and at last comparison between different configurations is given.