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. 74LS251 data selectors/multiplexers contain full on-chip binary decoding to select one-of-eight data sources and feature a strobe-controlled 3-STATE output.
74LS251 Features
- Tri-State Version of the 74LS151
- Interface Directly with the System Bus
- Perform Parallel to Serial Conversion
- Complementary Outputs Provide True and Inverted Data
- Standard TTL Switching Voltages
74LS251 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 |
74LS251 Pinout Diagram
74LS251 Pin Description
| Pin No | Pin Name | Description |
| 1 | I3 | Data Input 3 Of Multiplexer |
| 2 | I2 | Data Input 2 Of Multiplexer |
| 3 | I1 | Data Input 1 Of Multiplexer |
| 4 | I0 | Data Input 0 Of Multiplexer |
| 5 | Z | output Pin Of Multiplexer |
| 6 | Z’ | Invert Output Pin Of Multiplexer |
| 7 | E0 | Enable Output |
| 8 | GND | Ground |
| 9 | S2 | Data Select Pin |
| 10 | S1 | Data Select Pin |
| 11 | S0 | Data Select Pin |
| 12 | I7 | Data Input 7 Of Multiplexer |
| 13 | I6 | Data Input 6 Of Multiplexer |
| 14 | I5 | Data Input 5 Of Multiplexer |
| 15 | I4 | Data Input 4 Of Multiplexer |
| 16 | VCC | Positive Supply |
Applications
- Multiple data can be transmitted using a single line.
74LS251 Alternative Equivalent
74LS253, 74LS257
Download 74LS251 8-Channel Multiplexer Tri-State Datasheet from the link given below.
