Practical Cmos Video Decoder Chip Analog Front-end Clamp Circuit Of The Research And Design

This paper is to discover the clamp circuits for realizing video decoder IC (integrated circuit), and focusing on realizing the function of video clamp circuit and project design with CMOS process.For the 8-bit clamp circuits mainly including an 8-bit DAC (digital analog converter ,which can be shown as D/A), which function with a matching an Op Amp that turns the single ended signal to a full differential, so it is the point emphasized in this paper.To a 8-bit DAC which has no special order in speed and output range. But as we use UMC 0.18μM CMOS process which leads to a consideration about changes of models, thermometer and power source which can reach 45 combinations. At last, we select 9 combinations in worst conditions to do simulation, in order to reach a higher rate of finished products than 95 percent of it, which means that the design must reach a very high degree. By comparing the difference among current DAC, voltage DAC, capacitance DAC and hybrid DAC, we learn the types of DAC, characteristic and development more clearly. We can forecast that the hybrid DAC will have an important position in high speed and high accuracy fields, especially in the condition where the accuracy should be reached at least 10-bit. The paper introduces various design methods of Op Amp. It particularly introduces and explains the single ended Op Amp and full-differential Op Amp turning single ended signal to the dual ended, especially the full-differential Op Amp, which is original creation in this paper, and has not been published in literatures of domestic and abroad.The circuits and the system had been tested under CADENCE'S affirma analog circuit design environment. The result shows reaching and exceeding the target.