In VLSI application, adders play a very vital role. As we all know that the adders are most frequently used components in many circuits, so the designing of efficient adders is of main concern for researchers. This paper deals with the performance analysis of different adders like Ripple Carry Adder, Carry Look Ahead Adder, Carry Select Adder, Carry Save Adder, Kogge Stone Adder and Ladner Fischer Adder. The comparison is based on three performance parameters which are AREA, SPEED and MEMORY USAGE. KeywordsRipple Carry Adder, Carry Look Ahead Adder, Carry Select Adder, Carry Save Adder, Kogge-Stone Adder and Ladner Fischer Adder. 3. CARRY LOOK AHEAD ADDER Carry Look Ahead Adder solves the carry delay problem of Ripple Carry Adder by calculating the carry signals in advance based on input signal. Therefore Carry Look Ahead Adder is faster than Ripple Carry Adder. Carry Look Ahead Adder decreases the carry delay by using the lesser number of gates through which a carry signal must propagate in the generation and propagation stage. Carry Look Ahead Adder operation is based on two signals called P and G for each bit position. The P and G are expressed as Pi =Ai xor Bi Carry propagate----(3.1)
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