Design of approximate reverse carry select adder using RCPA.

An approximate carry select adder (CSLA) with reverse carry propagation (RCSLA) is showed in this work. This RCSLA was designed with reverse carry propagate full adder (RCPFA). In RCPFA structure, the carry signal propagates in the reverse direction that is from MSB part to LSB part, then the carry input has greater importance compared to the output carry. Three types of implementations were designed in RCPFA based on the design parameters. This method was applied to RCA & CSLA to design other types of approximate adders. These designs and simulations were done in CADENCE Software tool with 45 nm COMS technology. The design parameters of the three CSLA implementations with RCPFA are compared with the existing CSLA adders. [ABSTRACT FROM AUTHOR]