SDLS146B October 1976 – September 2016 SN54LS245 , SN74LS245
- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
- 8 Parameter Measurement Information
- 9 Detailed Description
- 10Application and Implementation
- 11Power Supply Recommendations
- 12Layout
- 13Device and Documentation Support
- 14Mechanical, Packaging, and Orderable Information
封裝選項(xiàng)
請(qǐng)參考 PDF 數(shù)據(jù)表獲取器件具體的封裝圖。
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- W|20
- J|20
- FK|20
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
訂購(gòu)信息
9 Detailed Description
9.1 Overview
The SNx4LS245 uses Schottky transistor logic to perform the standard '245 transceiver function. This standard logic function has a common pinout, direction select pin, and active-low output enable. When the outputs are disabled, the A and B sides of the device are effectively isolated.
9.2 Functional Block Diagram
Figure 3. Logic Diagram (Positive Logic)
9.3 Feature Description
9.3.1 3-State outputs
The 3-state outputs can drive bus lines directly. All outputs can be put into high impedance mode through the OE pin.
9.3.2 PNP Inputs
This device has PNP inputs which reduce dc loading on bus lines.
9.3.3 Hysteresis on Bus Inputs
The bus inputs have built-in hysteresis that improves noise margins.
9.4 Device Functional Modes
The SNx4LS245 performs the standard '245 logic function. Data can be transmitted from A to B or from B to A depending on the DIR pin value, or the A and B sides can be isolated from one another by setting the OE pin HIGH.
Table 1. Function Table
| INPUTS | OPERATION | |
|---|---|---|
| OE | DIR | |
| L | L | B data to A bus |
| L | H | A data to B bus |
| H | X | Isolation |
Figure 4. Schematics of Inputs and Outputs