Design, measurement and analysis of CMOS polysilicon TFT operational amplifiers

The small signal properties of polysilicon TFT opamps have been investigated in this paper. A method for the scaling of g/sub m/ (transconductance) and g/sub ds/ (output conductance) has been proposed, facilitating their estimates for various transistors in operational amplifiers. The analysis of two CMOS opamps fabricated by a low temperature, glass compatible poly-Si TFT process is demonstrated in comparison to the measured performance. The first implementation has been internally compensated with high load-driving capability (up to 36 pF), while the second one has employed a cascode stage for increased gain (56 dB).<
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