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The dependence of MOS amplifier performance on channel length and channel inversion is simulated and discussed. Suggestions are made regarding the optimization of voltage gain, nonlinear distortion and the gain-bandwidth product (GBW) through careful device length and inversion level selection. The midband voltage gain of the common-source amplifier is shown to remain relatively constant when biased for weak inversion operation, with short-channel devices continuing to amplify effectively at very low levels of inversion, allowing for extremely low power circuits. Total harmonic distortion is reduced through decreasing channel length and/or the level of channel inversion. The GBW is optimized through the use of minimum sized transistors biased to operate in the strong inversion region.