DESCRIPTION
The LS83A adds two 4-bit binary words (A plus B) plus the incoming carry. The binary sum appears on the sum outputs (∑1 – ∑4) and outgoing carry (C4) outputs. C0 + (A1+B1)+2(A2+B2)+4(A3+B3)+8(A4+B4) = ∑1+2∑2+4∑3+8∑4+16C4 Where: (+) = plus Due to the symmetry of the binary add function the LS83A can be used with either all inputs and outputs active HIGH (positive logic) or with all inputs and outputs active LOW (negative logic). Note that with active HIGH Inputs, Carry Input can not be left open, but must be held LOW when no carry in is intended. Example: C0 Logic Levels Active HIGH Active LOW L 0 1 A1 L 0 1 A2 H 1 0 A3 L 0 1 A4 H 1 0 B1 H 1 0 B2 L 0 1 B3 L 0 1 B4 H 1 0 ∑1 H 1 0 ∑2 H 1 0 ∑3 L 0 1 ∑4 L 0 1 C4 H 1 0 (10+9 = 19) (carry+5+6 = 12) Interchanging inputs of equal weight does not affect the operation, thus C0, A1, B1, can be arbitrarily assigned to pins 10, 11, 13, etc. FUNCTIONAL TRUTH TABLE C (n–1) L L L L H H H H An L L H H L L H H Bn L H L H L H L H ∑n L H H L H...
Motorola
