The 74LS83 is a high-speed 4-bit fuller Adder IC with the carry-out feature. The IC has four independent stages of full adder circuits in a single package. It is commonly used in applications where arithmetic operations are involved.
74LS83 Pin Configuration
| Pin Number | Pin Name | Description |
| 10,8,3,1 | A1, A2, A3, A4 | First Input for the adder circuit (Four pins for four stages) |
| 11,7,4,16 | B1, B2, B3, B4 | Second Input for the adder circuit (Four pins for four stages) |
| 13 | C0 | Carry Input – from the previous stage if present. |
| 9,6,2,15 | S1, S2, S3, S4 | Output pin for the Adder circuit (Four pins for four stages) |
| 14 | C4 | Carry Out the pin to cascade with other ICs. |
Specifications – 74LS83
- 4-bit Full Adder with Carry Out
- Nominal Operating Voltage: 5V
- Maximum Operating Voltage: 5.5V
- Output Propagation delay: 16nS
- Maximum Input Low Voltage: 0.8V
- Minimum Input High Voltage: 2V
- Available in a 16-pin PDIP package
Note: The Specifications are applicable when the IC is operating at 5V. Complete Technical Details can be found on the 74LS83 datasheet given at the end of this page.
Where to use 74LS83 IC
Although today we have cheap microcontrollers that can perform all arithmetic operations required for our application, in the early days ICs like Adder, Counter, flip-flops, etc were used for the same. This way the complexity and the BOM cost of the circuit design will greatly go low.
The 74LS83 is a Full Adder with Carry and Carry out features. It is a four-stage 4-bit counter, meaning it has four individual Full adder circuits each of 4-bit inside a single package. It can also be easily cascaded if more than four stages are required.
How to use a 74LS83 Full Adder IC
Using the Full Adder IC is pretty much straightforward. The IC has four different stages and each stage has two normal inputs Ax and Bx with an additional carry input called C1. Based on the values provided to these pins the output Sx will either be high (logic 1) or low (logic 0). The IC also has a Carry Out (CO) pin which will go high if the result has a carry. The block diagram below represents the same.
Each Full adder stage will obey the truth table below. Where Ai, Bi, and Ci are the input and SUM, and Co are the outputs.
The complete working will full simulation video can be found in the video linked below.
Applications
- High-Speed Arithmetic operations
- Miniature calculators
- Counters
- Simple logic control designs
