SN74LS181N

SN54/74LS181 4-BIT ARITHMETIC LOGIC UNIT The SN54 / 74LS181 is a 4-bit Arithmetic Logic Unit (ALU) which can perform all the possible 16 logic, operations on two variables and a variety of arithmetic operations. • Provides 16 Arithmetic Operations Add, Subtract, Compare, Double, • Provides all 16 Logic Operations of Two Variables Exclusive — OR, • Full Lookahead for High Speed Arithmetic Operation on Long Words • Input Clamp Diodes Compare, AND, NAND, OR, NOR, Plus Ten other Logic Operations Plus Twelve Other Arithmetic Operations 4-BIT ARITHMETIC LOGIC UNIT LOW POWER SCHOTTKY CONNECTION DIAGRAM DIP (TOP VIEW) VCC A1 24 23 B1 22 A2 21 B2 20 A3 19 B3 18 G Cn+4 17 16 P 15 A=B 14 F3 13 24 1 J SUFFIX CERAMIC CASE 623-05 N SUFFIX PLASTIC CASE 649-03 24 1 1 B0 2 A0 3 S3 4 S2 5 S1 6 S0 7 Cn 8 M 9 F0 10 F1 11 12 F2 GND ORDERING INFORMATION SN54LSXXXJ SN74LSXXXN Ceramic Plastic NOTE: The Flatpak version has the same pinouts (Connection Diagram) as the Dual In-Line Package. LOGIC SYMBOL PIN NAMES LOADING (Note a) HIGH A0 – A3, B0 – B3 S0 – S3 M Cn F0 – F3 A=B G P Cn+4 Operand (Active LOW) Inputs 1.5 U.L. Function — Select Inputs 2.0 U.L. Mode Control Input 0.5 U.L. Carry Input 2.5 U.L. Function (Active LOW) Outputs 10 U.L. Comparator Output Open Collector Carry Generator (Active LOW) 10 U.L. Output Carry Propagate (Active LOW) 10 U.L. Output Carry Output 10 U.L. LOW 0.75 U.L. 1.0 U.L. 0.25 U.L. 1.25 U.L. 5 (2.5) U.L. 5 (2.5) U.L. 10 U.L. 5 U.L. 5 (2.5) U.L. 7 8 6 5 4 3 Cn M 2 1 23 22 21 20 19 18 A0 B0 A1 B1 A2 B2 A3 B3 Cn+4 A=B G P F1 10 F2 11 F3 13 16 14 17 15 S0 S1 S2 S3 F 0 9 VCC = PIN 24 GND = PIN 12 NOTES: a. 1 TTL Unit Load (U.L.) = 40 µA HIGH/1.6 mA LOW. b. The Output LOW drive factor is 2.5 U.L. for Military (54) and 5 U.L. for Commercial (74) b. Temperature Ranges. FAST AND LS TTL DATA 5-332 SN54/74LS181 LOGIC DIAGRAM 7 8 2 1 23 22 21 20 19 18 Cn M A0 B0 A1 B1 A2 B2 A3 B3 S0 S1 5 S2 6 4 S3 3 VCC = PIN 24 GND = PIN 12 = PIN NUMBERS 9 F0 10 F1 A=B 14 11 F2 13 F3 P 15 16 Cn+4 G 17 FUNCTIONAL DESCRIPTION The SN54 / 74LS181 is a 4-bit high speed parallel Arithmetic Logic Unit (ALU). Controlled by the four Function Select Inputs (S0 . . . S3) and the Mode Control Input (M), it can perform all the 16 possible logic operations or 16 different arithmetic operations on active HIGH or active LOW operands. The Function Table lists these operations. When the Mode Control Input (M) is HIGH, all internal carries are inhibited and the device performs logic operations on the individual bits as listed. When the Mode Control Input is LOW, the carries are enabled and the device performs arithmetic operations on the two 4-bit words. The device incorporates full internal carry lookahead and provides for either ripple carry between devices using the Cn+4 output, or for carry lookahead between packages using the signals P (Carry Propagate) and G (Carry Generate), P and G are not affected by carry in. When speed requirements are not stringent, the LS181 can be used in a simple ripple carry mode by connecting the Carry Output (Cn+4) signal to the Carry Input (Cn) of the next unit. For high speed operation the LS181 is used in conjunction with the 9342 or 93S42 carry lookahead circuit. One carry lookahead package is required for each group of the four LS181 devices. Carry lookahead can be provided at various levels and offers high speed capability over extremely long word lengths. The A = B output from the LS181 goes HIGH when all four F outputs are HIGH and can be used to indicate logic equivalence over four bits when the unit is in the subtract mode. The A = B output is open collector and can be wired-AND with other A = B outputs to give a comparison for more then four bits. The A = B signal can also be used with the Cn+4 signal to indicate A>B and A