This work presents the mixed mode integrated circuit design. The development of SOC technology, CAD and simulation resources are providing system and chip designers with design tools necessary for successfully completing fully integrated CMOS hardware. The design methodology and new CAD/simulation tools allow the design engineer to focus on the mixed mode integrated circuit design without losing chip functionality or system level performance specifications. Integrated circuits-are designed, prototypes are fabricated, layout implemented and tested with varying degrees of automation. Very large scale integration (VLSI) systems have digital and analog components on the same chip. This shift from purely digital to mixed-signal (MS) systems is due to the high values of operating frequencies in communication circuits and shrinking feature sizes. Hardware description languages and simulators and automatic design software programs (called synthesizers) describe the functionality of each module as a "simulatable" model (also called a virtual prototype) and redesign or modification of the requirements is necessary if model need to meet the functional requirements of the module.