SEMICONDUCTOR INTEGRATED CIRCUIT DESIGNING METHOD AND SEMICONDUCTOR INTEGRATED CIRCUIT

PROBLEM TO BE SOLVED: To prevent characteristics of a pair of elements from unbalancing by forming a pair of elements constituting a differential circuit in respectively separate diffusing areas and providing a dummy element without constituting a circuit there when a dead space is generated in the periphery of the pair of elements. SOLUTION: The MOSFET PMOSA and PMOSD make a pair as the layout constitution example of an MOS differential circuit. A dummy MOSFET DM1 is arranged outside this PMOSA. This DM 1 is designed to be equal to a PMOSB or a PMOSC in a shape and size. Ad the size of elements arranged on both sides of the PMOSA and the PMOSD are equal in size, the parasitic capacitance between the diffusing areas of adjacent elements becomes equal and the characteristic of the elements becomes nearly equal between the PMOSA and the PMOSD. A pair of the PMOSB and the PMOSC and a pair of the NMOSA and the NMOSB are similar to this.