CD74HCT191
- 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 (AD) 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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技術文件
類型 | 標題 | 日期 | ||
---|---|---|---|---|
* | Data sheet | CD54HC190, CD74HC190, CD54HC191, CD74HC191, CD54HCT191, CD74HCT191 datasheet (Rev. E) | 2003年 10月 7日 | |
Application note | Implications of Slow or Floating CMOS Inputs (Rev. E) | 2021年 7月 26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 | ||
User guide | Signal Switch Data Book (Rev. A) | 2003年 11月 14日 | ||
Application note | TI IBIS File Creation, Validation, and Distribution Processes | 2002年 8月 29日 | ||
Application note | CMOS Power Consumption and CPD Calculation (Rev. B) | 1997年 6月 1日 | ||
Application note | Designing With Logic (Rev. C) | 1997年 6月 1日 | ||
Application note | SN54/74HCT CMOS Logic Family Applications and Restrictions | 1996年 5月 1日 | ||
Application note | Using High Speed CMOS and Advanced CMOS in Systems With Multiple Vcc | 1996年 4月 1日 |
設計與開發
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14-24-LOGIC-EVM — 適用於 14 針腳至 24 針腳 D、DB、DGV、DW、DYY、NS 和 PW 封裝的邏輯產品通用評估模組
14-24-LOGIC-EVM 評估模組 (EVM) 設計用於支援任何 14 針腳至 24 針腳 D、DW、DB、NS、PW、DYY 或 DGV 封裝的任何邏輯裝置。
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---|---|---|
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訂購與品質
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- 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
- 組裝地點