A static low-power, high-performance 32-bit carry skip adder

In this paper, we present a full-static carry-skip adder designed to achieve low power dissipation and high-performance operation. To reduce the adder's delay and power consumption, the adder is divided into variable-sized blocks that balance the inputs to the carry chain. The optimum block sizes for minimizing the critical path delay with complementary carry generation are achieved. Within blocks, highly optimized carry look-ahead logic, which computes block generate and block propagate signals, is used to further decrease delay. The adder architecture decreases power consumption by reducing the number of logic levels, glitches, and transistors. To achieve balanced delay, input bits are grouped unevenly in the carry chain. This grouping reduces active power by minimizing extraneous glitches and transitions. The adder has been implemented in 130nm CMOS technology. At 1.2V and 25C, typical performance is 1.086GHz and power dissipation normalized to 600 MHz operation is 0.786 mW.