High-speed and high-linearity input buffer

The invention discloses a high-speed high-linearity input buffer, and belongs to the technical field of analog integrated circuits. The high-speed high-linearity input buffer comprises a main source follower and an auxiliary source follower, the main source follower comprises an input tube and a tail current source, the grid electrode of the input tube is connected with an input signal of an inputbuffer, and the source electrode of the input tube serves as the output end of the input buffer and is connected with the tail current source; the drain electrode of the input tube is also connectedwith the input signal of the input buffer, so that the input tube drain potential of the input buffer provided by the invention is directly driven by the input signal, the source-drain voltage of theinput tube is kept unchanged basically, the influence of the source-drain resistance of the input tube can be ignored, and the linearity of the output signal is improved; and meanwhile, the auxiliarysource follower is used for