The 74LS series of integrated circuits (ICs) was one of the most popular logic families of transistor-transistor logic (TTL) logic chips. 74LS series is a bipolar, low-power Schottky IC. 74LS90 monolithic counters contain four master-slave flip-flops and additional gating to provide a divide-by-two counter and a three-stage binary counter.
74LS90 Features
- Contains a divide-by-two Counter and a Three Stage Binary Counter
- Count Frequency 42MHz
- Low Power Dissipation
- Operating Temperature up to 70°C
- Standard TTL Switching Voltages
74LS90 Specifications
| Supply Voltage | 4.75 – 5.25Vdc |
| Maximum Clock Frequency | 40Mhz |
| Power Dissipation | 2mW/gate @100kHz |
| Minimum Output Current | 8mA |
| Propagation Delay | 10nS |
| Fan Out (TTL Loads) | 20 |
74LS90 Pinout Diagram
74LS90 Pin Description
| Pin No | Pin Name | Description |
| 1 | CP1′ | Invert Clear Pin 1 |
| 2 | MR1 | Master Reset 1 |
| 3 | MR2 | Master Reset 2 |
| 4 | NC | Not Connected |
| 5 | VCC | Positive Supply |
| 6 | MS1 | Master Set 1 |
| 7 | MS2 | Master Set 2 |
| 8 | Q2 | Output Q2 |
| 9 | Q1 | Output Q1 |
| 10 | GND | Ground Pin |
| 11 | Q3 | Output Q3 |
| 12 | Q0 | Output Q0 |
| 13 | NC | Not Connected |
| 14 | CP0′ | Invert Clear Pin 0 |
74LS90 Circuit
Here is a simple circuit of Mod 10 Counter using 74LS90 IC.
Applications
- Clock generation
- Clock division
- Integrated oscillator
- Low power cmos
- TTL compatible inputs
- In frequency counting circuit
74LS90 Alternative Equivalent
74LS162, 74LS190
Download 74LS90 Decade Counter Datasheet from the link given below.
