Overview
The SN74LS245DWR, produced by Texas Instruments, is an octal bus transceiver with 3-state outputs. This device is designed for asynchronous two-way communication between data buses, making it ideal for various digital systems that require bidirectional data transfer. The control-function implementation minimizes external timing requirements, allowing data transmission from the A bus to the B bus or vice versa based on the logic level at the direction-control (DIR) input. Additionally, the output-enable (OE) input can disable the device, effectively isolating the buses.
Key Specifications
| Parameter | Description |
|---|---|
| Package | SOIC (DW), 20 pins |
| Operating Temperature Range | 0°C to 70°C |
| Supply Voltage | 4.75 V to 5.25 V |
| High Level Output Current | -15 mA |
| Low Level Output Current | 24 mA |
| Number of Bits | 8 |
| Number of Channels | 8 |
| Propagation Delay | 12 ns (typical) |
| Quiescent Current | 62 mA |
| Dimensions | Length: 12.8 mm, Width: 7.5 mm, Height: 2.65 mm, Thickness: 2.35 mm |
Key Features
- 3-State Outputs: Drive bus lines directly and can be put into high impedance mode through the OE pin.
- PNP Inputs: Reduce DC loading on bus lines.
- Hysteresis at Bus Inputs: Improves noise margins.
- Bidirectional Data Transfer: Allows data transmission from A bus to B bus or from B bus to A bus based on the DIR input.
- Output Enable: The OE input can disable the device, isolating the buses.
Applications
The SN74LS245DWR is suitable for a variety of applications, including:
- Electronic Point of Sale: For bidirectional communication in POS systems.
- Factory Automation and Control: In industrial control systems requiring reliable data transfer.
- Test and Measurement: For equipment that needs to communicate data between different buses.
Q & A
- What is the primary function of the SN74LS245DWR? The primary function is to enable asynchronous two-way communication between data buses.
- How does the direction of data transfer get controlled? The direction of data transfer is controlled by the logic level at the direction-control (DIR) input.
- What is the purpose of the OE input? The OE input can disable the device, effectively isolating the buses.
- What are the operating temperature and voltage ranges for the SN74LS245DWR? The operating temperature range is 0°C to 70°C, and the supply voltage range is 4.75 V to 5.25 V.
- What is the propagation delay of the SN74LS245DWR? The typical propagation delay is 12 ns.
- Does the SN74LS245DWR have built-in hysteresis? Yes, it has built-in hysteresis at the bus inputs to improve noise margins.
- What type of inputs does the SN74LS245DWR have? It has PNP inputs which reduce DC loading on bus lines.
- How many bits and channels does the SN74LS245DWR support? It supports 8 bits and 8 channels.
- What is the quiescent current of the SN74LS245DWR? The quiescent current is 62 mA.
- What are some common applications of the SN74LS245DWR? Common applications include electronic point of sale, factory automation, and test and measurement equipment.
