DM74S182

Supply Voltage . . . . . . . . . . . .  . . . . . .  . . . . . .  . . . . . .  . . . . . .  . . . . . .  . 7V
Input Voltage  . . . . . .  . . . . . .  . . . . . .  . . . . . . . . .  . . .  . . . . . .  . . . . . . 5.5V
Operating Free Air Temperature Range . . . . . .   . . . . . . . . . .  0°C to +70°C
Storage Temperature Range  . . . . . .  . . . . . .  . . . . . .  . . . -65°C to +150°C

Note 1: The "Absolute Maximum Ratings" are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The "Recommended Operating Conditions" table will define the conditions for actual device operation.

These DM74S182 circuits are high-speed, look-ahead carry generators, 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, generatecarry, and propagate-carry functions are provided as shown in the pin designation table.

When used in conjunction with the 181 arithmetic logic unit, these DM74S182 generators provide high-speed carry look-ahead capability for any word length. Each DM74S182 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 look-ahead 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 181 data sheet are also applicable to and compatible with the look-ahead generator. Positive logic equations for the DM74S182 are:
   C_n + x = G0 + P0 Cn
   C_n + y = G1 + P1 G0 + P1 P0 C_n
   C_n + z = G2 + P2 G1 + P2 P1 G0 + P2 P1 P0 C_n
   G = G3 (P3 + G2) (P3 + P2 + G1) (P3 + P2 + P1 + G0)
   P = P3 P2 P1 P0