The Principle And Application Of Operational Transconductance Amplifier

The design of analog integrated circuit derives itself from the development of VLSI technique and the urgent requirement of electronic system integration .Filter is an important unit of analog integrated circuit, whose structure construction and design method can extend to the design of large scale analog integrated circuit .Operational Transconductance Amplifier (abbreviation: OTA), it has very good performance advantage and obvious practical and theoretical value , the huge interest that has aroused circuit and systematic academic circles.In this paper, the principle and design of Operational Transconductance Amplifier (abbreviation: OTA) and its circuit about application have been studied. Firstly, the development of current mode circuit and OTA are briefly introduced. Secondly, some basic theories and classical methods of analog filter are introduced in this paper. With the model circuit, this paper introduces the principle of OTA. Then, the analogue signal processing and operation circuits with the active network elements using OTA have been induced overall: amplifier,adder,integrator based on OTA.Based on the domestic and foreign research results the article proposed a new versatile filter based on dual output transconductance amplifiers. The proposed circuit has simple structure, excellent high-frequency performance .A voltage mode arbitrary order OTA-C multifunction filter is proposed. A new way to design n-order OTA and CCII current-mode versatile filter by signal flow graph is presented.It is possible to realize low pass, high pass, band psaa, band stop and all pass by suitable choosing the outputs. A new way to design nth-order MOCCCII and CCII- current-mode low-pass filter by signal flow graph is presented. The filter has some advantages such as fewer components, all the capacitors being grounded. The n-order filters only composed by one ccii- and n MOCCCIIs and capacitors. The circuit is integrated conveniently and is compatible with VLSI technology.Finally, sine oscillators using OTA also have been introduced, a sine oscillation circuit using OTAs has been presented, which can realize independence adjustment about frequency and condition of oscillation. All filter and oscillator proposed are all proved by the PSpice simulation, the simulation results have been consistent with the theoretical analysis results.