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. 74LS55 2 wide 4-input AND/OR invert gate contain 2-wide 4-input AND-OR INVERT gates. They perform the Boolean function Y = ABCD’ + EFGH’.

74LS55 Features
- 2 wide 4-input AND/OR invert gate
- Standard Pin Arrangement
- Fast Switching Times
- Operating Temperature up to 70°C
- Standard TTL Switching Voltages
74LS55 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 |
74LS55 Pinout Diagram

74LS55 Pin Description
| Pin No | Pin Name | Description |
| 1 | A1 | AND Gate 1 Input 1 |
| 2 | B1 | AND Gate 1 Input 2 |
| 3 | C1 | AND Gate 1 Input 3 |
| 4 | D1 | AND Gate 1 Input 4 |
| 5 | NC | No Connection |
| 6 | NC | No Connection |
| 7 | GND | Ground |
| 8 | Y | OR Inverter Gate Output |
| 9 | NC | No Connection |
| 10 | A2 | AND Gate 2 Input 1 |
| 11 | B2 | AND Gate 2 Input 2 |
| 12 | C2 | AND Gate 2 Input 3 |
| 13 | D2 | AND Gate 2 Input 4 |
| 14 | VCC | Positive Supply |
74LS55 Circuit
Applications
74LS55 Alternative Equivalent
74LS51, 74LS54
Download 74LS55 2 WIDE 4-INPUT AND/OR INVERT GATE Datasheet from the link given below.




