Your Cart

74LS181 4-Bit Arithmetic Logic Unit IC/Function generator

74LS181 4-Bit Arithmetic Logic Unit IC/Function generator
74LS181 4-Bit Arithmetic Logic Unit IC/Function generator

Write a review

Please login or register to review
KES 300.00
  • Stock: In Stock
  • Model: 74LS181
  • SKU: 3629

The 74LS181 IC is an arithmetic logic unit / function generator IC that has a complexity of 75 congruent gates on a monolithic IC chip. These circuits perform 16 binary arithmetic operations on two 4-bit words. These operations are selected by the four function-select lines (S0, S1, S2, S3) and include addition, subtraction, decrement, and straight transfer. The 74LS181 IC also constitutes a wide array of features such as thermal overload protection & ESD protection. The IC 74LS181 is smaller in size and it has a much faster speed which makes it reliable in every kind of device. The design concentrates on the chip to be used in high-performance applications such as memory-decoding.

What is an ALU/Function Generator?

The arithmetic logic unit (ALU) is a combinational digital circuit that performs arithmetic and bitwise operations on integer binary numbers. It performs a variety of arithmetic & logical operations on its inputs (better known as operands) such as simple addition, subtraction, multiplication, division, and logic operations, such as OR and AND. The control unit (CU) fetches the instructions & operative data from the memory and uses operations of the ALU to carry out those instructions using that data.

74LS181 Pinout

74LS181 Pin Configuration

Pin NoPin NameDescription
1B0Active low Operand Input B0
2A0Active low Operand Input
3S3Function Select Input S3
4S2Function Select Input S2
5S1Function Select Input S1
6S0Function Select Input S0
7CnCarry Input
8MMode Control Input
9F0Function Output F0
10F1Function Output F1
11F2Function Output F2
12GNDGround Pin
13F3Function Output F3
14A=BComparator Output
15P’Active low carry propagate
16Cn+4Carry Output
17G’Active low carry generator
18B3Active low Operand Input B3
19A3Active low Operand Input A3
20B2Active low Operand Input B2
21A2Active low Operand Input A2
22B1Active low Operand Input B1
23A1Active low Operand Input A1
24VCCChip Supply Voltage

74LS181 Features & Specifications

  • Technology Family: LS
  • Rating: Catalog
  • Balanced propagation delays
  • Designed specifically for high speed
  • Product type: Standard
  • Provides 16 Arithmetic Operations Add, Subtract, Compare, Double, Plus Twelve Other Arithmetic Operations
  • Provides all 16 Logic Operations of Two Variables Exclusive OR, Compare, AND, NAND, OR, NOR, Plus Ten other Logic Operations
  • Full Lookahead for High Speed Arithmetic Operation on Long Words
  • Input Clamp Diodes
  • VCC (min): 4.75V
  • VCC (max): 5.25V
  • Typical propagation delay: 21nS
  • Low power consumption: 32mW
  • ESD protection
  • Operating temperature: 0ºC to 70ºC


  • In computer system architecture design, When operative speed requirements are not stringent, it can be used to serve 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 IC is used in conjunction with the 9342 or 93S42 carry look ahead circuit.


The product is currently Out-of-Stock. Please enter your details below and we will notify you as soon as the product is available.