74LS640 Octal Inverting Bus Transceiver Tri-State
Package PDIP, SOIC Series 74LS
74LS640 overview
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. 74LS640 octal bus transceivers are designed for asynchronous two-way communication between data buses The devices transmit data from the A bus to the B bus or from the B bus to the A bus depending upon the level at the direction control (DIR) input
Key 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
Datasheet
640.pdf
74LS640 features
- Designed for Asynchronous two-way Communication between Data Buses
- Enable Input for Disabling the Device
- 3-State Outputs Drive Bus Lines Directly
- Operating Temperature up to 70°C
- Standard TTL Switching Voltages
74LS640 pinout
| Pin | Name | Description |
|---|---|---|
| 1 | T/R' | Control Pin |
| 2 | A0 | Input / Output Of Bus Transceiver A |
| 3 | A1 | Input / Output Of Bus Transceiver A |
| 4 | A2 | Input / Output Of Bus Transceiver A |
| 5 | A3 | Input / Output Of Bus Transceiver A |
| 6 | A4 | Input / Output Of Bus Transceiver A |
| 7 | A5 | Input / Output Of Bus Transceiver A |
| 8 | A6 | Input / Output Of Bus Transceiver A |
| 9 | A7 | Input / Output Of Bus Transceiver A |
| 10 | GND | Ground |
| 11 | B7 | Input / Output Of Bus Transceiver B |
| 12 | B6 | Input / Output Of Bus Transceiver B |
| 13 | B5 | Input / Output Of Bus Transceiver B |
| 14 | B4 | Input / Output Of Bus Transceiver B |
| 15 | B3 | Input / Output Of Bus Transceiver B |
| 16 | B2 | Input / Output Of Bus Transceiver B |
| 17 | B1 | Input / Output Of Bus Transceiver B |
| 18 | B0 | Input / Output Of Bus Transceiver B |
| 19 | OE' | Enable Pin 2 |
| 20 | VCC | Positive Supply |
74LS640 applications
- Provide bidirectional, input or output control, of either digital or analogue devices to a common shared data bus
More about 74LS640
74LS640 Alternative Equivalent
74LS645
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