SN74F657
- Combines ´F245 and ´F280B Functions in One Package
- High-Impedance N-P-N Inputs for Reduced Loading (70 uA in Low and High States)
- High Output Drive and Light Bus Loading
- 3-State B Outputs Sink 64 mA and Source 15 mA
- Input Diodes for Termination Effects
- Package Options Include Plastic Small-Outline Packages and Standard Plastic 300-mil DIPs
The SN74F657 contains eight noninverting buffers with 3-state outputs and an 8-bit parity generator/checker. It is intended for bus-oriented applications. The buffers have a specified current sinking capability of 24 mA at the A port and 64 mA at the B port.
The transmit/receive (T/R\) input determines the direction of the data flow through the bidirectional transceivers. When T/R\ is high, data is transmitted from the A port to the B port. When T/R\ is low, data is received at the A port from the B port.
When the output enable (
)
input is high, both the A and B ports are placed in a high-impedance
state (disabled). The ODD/EVEN\ input allows the user to select
between odd or even parity systems. When transmitting from A port to
B port (T/R\ high), PARITY is an output from the generator/checker.
When receiving from B port to A port (T/R\ low), PARITY is an input.
When transmitting (T/R\ high), the parity select (ODD/EVEN\) input is made high or low as appropriate. The A port is then polled to determine the number of high bits.The PARITY output goes to the logic state determined by ODD/EVEN\ and the number of high bits on A port. When ODD/EVEN\ is low (for even parity) and the number of high bits on A port is odd, the PARITY will be high, transmitting even parity. If the number of high bits on A port is even, the PARITY will be low, keeping even parity.
When in the receive mode (T/R\ low), the B port is polled to determine the number of high bits. If ODD/EVEN\ is low (for even parity) and the number of highs on B port is:
- 1. Odd and the PARITY input is high, then ERR\ will be high signifying no error.
- 2. Even and the PARITY input is high, then ERR\ will be low indicating an error.
The SN74F657 is characterized for operation from 0°C to 70°C.
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技術文件
| 類型 | 標題 | 日期 | ||
|---|---|---|---|---|
| * | Data sheet | Octal Transceiver With Parity Generator/Checker And 3-State Outputs datasheet (Rev. A) | 1993年 10月 1日 | |
| Selection guide | Logic Guide (Rev. AB) | 2017年 6月 12日 | ||
| Application note | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 2015年 12月 2日 | ||
| User guide | LOGIC Pocket Data Book (Rev. B) | 2007年 1月 16日 | ||
| Application note | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 2004年 7月 8日 | ||
| Application note | TI IBIS File Creation, Validation, and Distribution Processes | 2002年 8月 29日 | ||
| Application note | Bus-Interface Devices With Output-Damping Resistors Or Reduced-Drive Outputs (Rev. A) | 1997年 8月 1日 | ||
| Application note | Designing With Logic (Rev. C) | 1997年 6月 1日 | ||
| Application note | Input and Output Characteristics of Digital Integrated Circuits | 1996年 10月 1日 |
設計與開發
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| 封裝 | 引腳 | 下載 |
|---|---|---|
| SOIC (DW) | 24 | 檢視選項 |
訂購與品質
- RoHS
- REACH
- 產品標記
- 鉛塗層/球物料
- MSL 等級/回焊峰值
- MTBF/FIT 估算值
- 材料內容
- 資格摘要
- 進行中可靠性監測
- 晶圓廠位置
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