ASIC IMPLEMENTATION OF 16 BIT CARRY SELECT ADDER

Adders are the basic building blocks of any processor or data path application. In adder design carry generation is the critical path. To reduce the power consumption of data path we need to reduce Area of the adder. Carry Select Adder is one of the fast adder used in may data path applications. The proposed design is implemented without using multiplexer and RCA structure with Cin=1. Instead of multiplexer and RCA Cin=1 structure hear we used simple combinational circuit which consists AND and XOR gates. In this proposed design has reduced Area and power as compared with regular CSLA and modified BEC(Binary to Excess-One Converter) CSLA with slight increase in the delay. . In the proposed scheme, the carry select (CS) operation is scheduled before the calculation of final-sum, which is different from the conventional approach. Bit patterns of two anticipating carry words (corresponding to Cin = 0 and 1) and fixed Cin bits are used for logic optimization of CS and generation units. An efficient CSLA design is obtained using optimized logic units. The proposed 16-bit CSLA design involves significantly less area and delay than the recently proposed BEC-based CSLA. Due to the small carry-output delay, the proposed CSLA design is a good candidate for square-root (SQRT) CSLA.