| 摘要 |
PURPOSE:To enable a number of cells to be placed and increase the degree of freedom of functions by dividing an I/O buffer part into further small primitive cells and selecting the standard cell system. CONSTITUTION:A primitive cell is prepared where a cell row 2 at an N-channel transistor part constituting an output high drive CMOS transistor which also functions as an I/O electrostatic protection element, a cell row 3 at a P-channel transistor part, and a cell row 4 having a taper circuit of an input buffer circuit and an output high drive transistor are designed at a specified cell height for each function. Then, to obtain a desired buffer circuit, each cell row and wiring areas 5 to 7 are alternately provided and the input buffer circuit, the output buffer circuit, and an I/O bidirectional buffer circuit is constituted in the standard cell system. It increases the degree of freedom for each handling function. |
