Abstract: This research concerns a set of proposals in order to structuring the design of MOS analog VLSI. They are derived from structured logic design methods, which have shown their great efficiency. We propose, by using NMOS inverter as linear amplifier, a simple method to go from functional to structural description. So it was possible to confirm that the designed circuit will work exactly as it was predicted by functional simulation results. This method has been, successfully and efficiently applied to the design of a PLL.