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CD74HCT191

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高速 CMOS 逻辑可预设的同步 4 位二进制加/减计数器

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数据表

CD74HCT191

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产品详情

Function Counter Bits (#) 4 Technology family HCT Supply voltage (min) (V) 4.5 Supply voltage (max) (V) 5.5 Input type TTL-Compatible CMOS Output type Push-Pull Features Balanced outputs, High speed (tpd 10-50ns), Positive input clamp diode, Presettable Operating temperature range (°C) -55 to 125 Rating Catalog
Function Counter Bits (#) 4 Technology family HCT Supply voltage (min) (V) 4.5 Supply voltage (max) (V) 5.5 Input type TTL-Compatible CMOS Output type Push-Pull Features Balanced outputs, High speed (tpd 10-50ns), Positive input clamp diode, Presettable Operating temperature range (°C) -55 to 125 Rating Catalog
PDIP (N) 16 181.42 mm² 19.3 x 9.4 SOIC (D) 16 59.4 mm² 9.9 x 6
  • 2-V to 6-V VCC Operation (’HC190,191)
  • 4.5-V to 5.5-V VCC Operation (’HCT191)
  • Wide Operating Temperature Range of –55 to 125°C
  • Synchronous Counting and Asynchronous Loading
  • Two Outputs for n-Bit Cascading
  • Look-Ahead Carry for High-Speed Counting
  • Balanced Propagation Delay and Transition Times
  • Standard Outputs Drive Up To 15 LS-TTL Loads
  • Significant Power Reduction Compared to LS-TTL Logic ICs
  • 2-V to 6-V VCC Operation (’HC190,191)
  • 4.5-V to 5.5-V VCC Operation (’HCT191)
  • Wide Operating Temperature Range of –55 to 125°C
  • Synchronous Counting and Asynchronous Loading
  • Two Outputs for n-Bit Cascading
  • Look-Ahead Carry for High-Speed Counting
  • Balanced Propagation Delay and Transition Times
  • Standard Outputs Drive Up To 15 LS-TTL Loads
  • Significant Power Reduction Compared to LS-TTL Logic ICs

The CD54/74HC190 are asynchronously presettable BCD decade counters, whereas the CD54/74HC191 and CD54/74HCT191 are asynchronously presettable binary counters.

Presetting the counter to the number on preset data inputs (A–D) is accomplished by a low asynchronous parallel load (LOAD)\ input. Counting occurs when LOAD\ is high, count enable (CTEN)\ is low, and the down/up (D/U) input is either high for down counting or low for up counting. The counter is decremented or incremented synchronously with the low-to-high transition of the clock.

When an overflow or underflow of the counter occurs, the MAX/MIN output, which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high-speed cascading (see Figure 1). The MAX/MIN output also initiates the ripple clock (RCO)\ output, which is normally high, goes low and remains low for the low-level portion of the clock pulse. These counters can be cascaded using RCO\ (see Figure 2).

If a decade counter is preset to an illegal state or assumes an illegal state when power is applied, it returns to the normal sequence in one or two counts, as shown in the state diagrams (see Figure 3).

The CD54/74HC190 are asynchronously presettable BCD decade counters, whereas the CD54/74HC191 and CD54/74HCT191 are asynchronously presettable binary counters.

Presetting the counter to the number on preset data inputs (A–D) is accomplished by a low asynchronous parallel load (LOAD)\ input. Counting occurs when LOAD\ is high, count enable (CTEN)\ is low, and the down/up (D/U) input is either high for down counting or low for up counting. The counter is decremented or incremented synchronously with the low-to-high transition of the clock.

When an overflow or underflow of the counter occurs, the MAX/MIN output, which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high-speed cascading (see Figure 1). The MAX/MIN output also initiates the ripple clock (RCO)\ output, which is normally high, goes low and remains low for the low-level portion of the clock pulse. These counters can be cascaded using RCO\ (see Figure 2).

If a decade counter is preset to an illegal state or assumes an illegal state when power is applied, it returns to the normal sequence in one or two counts, as shown in the state diagrams (see Figure 3).
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类型 标题 下载最新的英语版本 日期
* 数据表 CD54HC190, CD74HC190, CD54HC191, CD74HC191, CD54HCT191, CD74HCT191 数据表 (Rev. E) 2003年 10月 7日
应用手册 Implications of Slow or Floating CMOS Inputs (Rev. E) 2021年 7月 26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
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用户指南 Signal Switch Data Book (Rev. A) 2003年 11月 14日
应用手册 TI IBIS File Creation, Validation, and Distribution Processes 2002年 8月 29日
应用手册 CMOS Power Consumption and CPD Calculation (Rev. B) 1997年 6月 1日
应用手册 使用逻辑器件进行设计 (Rev. C) 1997年 6月 1日
应用手册 SN54/74HCT CMOS Logic Family Applications and Restrictions 1996年 5月 1日
应用手册 Using High Speed CMOS and Advanced CMOS in Systems With Multiple Vcc 1996年 4月 1日

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英语版 (Rev.B): PDF | HTML
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包含信息：
  • RoHS
  • REACH
  • 器件标识
  • 引脚镀层/焊球材料
  • MSL 等级/回流焊峰值温度
  • MTBF/时基故障估算
  • 材料成分
  • 鉴定摘要
  • 持续可靠性监测
包含信息：
  • 制造厂地点
  • 封装厂地点

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