Abstract: We provide an automatic verification and optimization tool to compare circuit with design specification in mixed signal design.The proposed tool can automatically compare the behavior model of design specification with circuit level design for both function and performance.If performance is mismatched, circuit sizing optimization is performed to make sure design meet both functional and performance specification.Waveform comparison is used for the functional check.Differential evolution (DE) is used for performance matching and circuit optimization.The optimization feature can also save the design efforts and achieve smaller area and power compare to manually circuit sizing.