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. 74LS20 Dual 4-input NAND Gate contains two independent 4 input NAND gate

74LS20 Features
- Two Independent NAND Gates
- Standard Pin Configuration
- Fast Switching Times
- Operating Temperature up to 70°C
- Standard TTL Switching Voltages
74LS20 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 |
74LS20 Pinout Diagram

74LS20 Pin Description
Pin No | Pin Name | Description |
1 | A1 | NAND Gate 1 Input 1 |
2 | B1 | NAND Gate 1 Input 2 |
3 | NC | No Connection |
4 | C1 | NAND Gate 1 Input 3 |
5 | D1 | NAND Gate 1 Input 4 |
6 | X1 | NAND Gate 1 Output |
7 | GND | Ground |
8 | X2 | NAND Gate 2 Output |
9 | A2 | NAND Gate 2 Input 1 |
10 | B2 | NAND Gate 2 Input 2 |
11 | NC | No Connection |
12 | C2 | NAND Gate 2 Input 3 |
13 | D2 | NAND Gate 2 Input 4 |
14 | VCC | Positive Supply |
74LS20 Circuit
Applications
- Freezer warning buzzer circuits
- Automatic temperature control circuits
74LS20 Alternative Equivalent
74LS03, 74LS10
Download 74LS20 Dual 4-input NAND Gate Datasheet from the link given below.