MM54HC182/MM74HC182 Look-Ahead Carry Generator General Description The MM54HC182/MM74HC182 is a high speed LOOKAHEAD CARRY GENERATOR utilize advanced silicon-gate CMOS technology. It has the low power consumption and high noise immunity of standard CMOS integrated circuits, along with the ability to drive 10 LS-TTL loads. These circuits are capable of anticipating a carry across four binary adders or groups of adders. They are cascadable to perform full look-ahead across n-bit adders. Carry, generate- carry, and propagate-carry functions are provided as shown in the pin designation table. When used in conjunction with the HC181 arithmetic logic unit, these generators provide high-speed carry look-ahead capability for any word length. Each HC182 generates the look-ahead (anticipated carry) across a group of four ALU's and, in addition, other carry look-ahead circuits may be employed to anticipate carry across sections of four lookahead packages up to n-bits. The method of cascading circuits to perform multi-level look-ahead is illustrated under typical application data. Carry input and output of the ALU's are in their true form, and the carry propagate (P) and carry generate (G) are in negated form; therefore, the carry functions (inputs, outputs, generate, and propagate) of the look-ahead generators are implemented in the compatible forms for direct connection to the ALU. Reinterpretations of carry functions as explained on the HC181 data sheet are also applicable to and compatible with the look-ahead generator.