Decade counter (SN74LS90) 7490
Datasheet
The datasheet for Decade counter (SN74LS90) 7490 provides complete technical information including pin diagram, electrical characteristics and typical applications.
Category: Counters | Type: BCD Counter (mod-10) | Configuration: 4 BCD outputs, 2 clock inputs
The SN74LS90 is a decade counter (divide by 10). It consists of four master-slave flip-flops and logic for binary/BCD counting. It provides QA...QD outputs; can obtain a square wave of 10 (or cycle of 10) by connecting QD to the clock input. It has synchronous reset and preset. Widely used for BCD digit counters in educational projects.
Applications
- BCD digit counters
- Frequency dividers
- Digital clocks
- Event counters
- Sequence generators
These applications show the versatility of the component in different areas of electronics.
Truth Table
The truth table for the sn74ls90 decade counter shows all possible input combinations and their corresponding output.
| Count | QD | QC | QB | QA |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 |
| 1 | 0 | 0 | 0 | 1 |
| 2 | 0 | 0 | 1 | 0 |
| 3 | 0 | 0 | 1 | 1 |
| 4 | 0 | 1 | 0 | 0 |
| 5 | 0 | 1 | 0 | 1 |
| 6 | 0 | 1 | 1 | 0 |
| 7 | 0 | 1 | 1 | 1 |
| 8 | 1 | 0 | 0 | 0 |
| 9 | 1 | 0 | 0 | 1 |
Technical Specifications
General Information
BCD Counter (mod-10)
4 BCD outputs, 2 clock inputs
SN74LS90
Electrical Characteristics
4.75V - 5.25V
0.8mA per input
35MHz max
0掳C to +70掳C
DIP-14
2.54mm
16ns typical
Additional Information
The sn74ls90 decade counter is a fundamental component in the counters category. Its design and characteristics make it ideal for a wide range of applications in digital electronics.
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