CD40117B
- One standard "B" output will drive eight terminator circuits.
- Will terminate a CMOS data bus with up to 40 B-series inputs inputs or 3-state outputs connected at VDD of 5 V.
- Input terminal protected by standard "B" series ESD protection network.
- Preserves final logic state.
- Output after switching is closer to VDD or VSS rail than with a resistor.
- Requires only one solder connection.
- Open circuited terminator not used will not affect performance.
- Can be connected to any CMOS I/O line.
- Draws current only when logic state is changing.
- Can be preset.
- Applications
- Error state identification.
- Replaces pull-up or pull-down resistors
- Avoids floating inputs in modular systems
- Sharpens transistors (hysteresis)
- Anti-bounce circuit
NOT RECOMMENDED FOR NEW DESIGNS
CD40117B is a dual 4-bit terminator that can be programmed by means of STROBE and DATA control bits to function as pull-up or pull-down resistors. The CD40117B can also be programmed to function as latches to terminate any open or unused CMOS logic when used with 3-state logic or during a power-down condition. Considerable savings in power and board space can be realized when this device is used to replace pull-up or pull-down resistors. When the STROBE is in the logic "1" state, the terminator functions as a pull-up resistor if the DATA input is a logic "1" or as a pull down resistor if the DATA input is a logic "0".
When the STROBE is in the logic "0" state, the terminator performs the latch functions, i.e., it follows the changing states of the bus. If the bus goes into the high-Z state or into a power-down condition, the latched terminator retains the data ("1" or "0") that the bus carried before it switched to the high-Z or power-down state. If and when the bus changes from the high-Z state to the state opposite to that which the latch is storing, the bus will override the latch and the terminator will reflect the state on the bus. The small geometries chosen for the inverters in the latch allow this override mode. When checking the data bus whose last state is being preserved by the terminator, a resistor should be used in series with the probe whose input capacitance could trip the small latches. The resistance should be in excess of the output impedance of the latch, i.e., R should be > 30 K at VDD = 10 V.
The STROBE and DATA inputs in each section can be paralleled allowing this device to be used as an 8-bit bus terminator.
The CD40117B types are supplied in 14-lead dual-in-line plastic packages (E suffix), 14-lead small-outline packages (M, MT, M96, and NSR suffixes), and 14-lead thin shrink small-outline packages (PW and PWR suffixes).
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类型 | 标题 | 下载最新的英语版本 | 日期 | |||
---|---|---|---|---|---|---|
* | 数据表 | CD40117B TYPES 数据表 (Rev. C) | 2003年 8月 21日 | |||
选择指南 | Logic Guide (Rev. AB) | 2017年 6月 12日 | ||||
应用手册 | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 2015年 12月 2日 | ||||
选择指南 | 逻辑器件指南 2014 (Rev. AA) | 最新英语版本 (Rev.AB) | 2014年 11月 17日 | |||
用户指南 | LOGIC Pocket Data Book (Rev. B) | 2007年 1月 16日 | ||||
应用手册 | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 2004年 7月 8日 | ||||
用户指南 | Signal Switch Data Book (Rev. A) | 2003年 11月 14日 | ||||
应用手册 | Understanding Buffered and Unbuffered CD4xxxB Series Device Characteristics | 2001年 12月 3日 |
设计和开发
如需其他信息或资源,请点击以下任一标题进入详情页面查看(如有)。
14-24-LOGIC-EVM — 采用 14 引脚至 24 引脚 D、DB、DGV、DW、DYY、NS 和 PW 封装的逻辑产品通用评估模块
14-24-LOGIC-EVM 评估模块 (EVM) 旨在支持采用 14 引脚至 24 引脚 D、DW、DB、NS、PW、DYY 或 DGV 封装的任何逻辑器件。
封装 | 引脚 | 下载 |
---|---|---|
PDIP (N) | 14 | 查看选项 |
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