Adders are an electronic circuit which adds the addend, augends numbers with or without previous carry generated and provides the summations and carries as a result. The adder differs in the type of inputs considered and algorithm used for example Binary, BCD, Excess-3, Hexadecimal adders etc. The 1’s complement method, 2’s complement method, signed arithmetic etc. The adders widely used in ADCs, digital voltmeters, CPUs of microprocessors, micro-controllers. It also extensively used calculating the memory addresses, table indices, and offsets. Binary adders are the most commonly used adders in which 2’scomplement or1’scomplement is used to represent negative number. Another approach of adder design includes low power module, high speed, large bandwidths or channels. Numerous adders are designed by making tradeoffs between power, propagation delay and size. In most of the digital adders, speed of addition is limited by the time required to transmit a carry through the adder. Carry Select Adder (CSlA) is one of the fastest adders fabricated with data-processing processors to perform fast arithmetic operations. This paper presents a review on CSlA.
Keywords: ADCs, RCA, Delay, LSB, CSkA, CSlA,