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).
CD74HC190 | |
Rating | Catalog |
Technology Family | HC |
器件 | 状态 | 温度 | 价格 | 封装 | 引脚 | 封装数量 | 封装载体 | 丝印标记 |
CD74HC190E | ACTIVE | -55 to 125 | 0.90 | 1ku | PDIP (N) | 16 | 25 | TUBE | |
CD74HC190EE4 | ACTIVE | -55 to 125 | 0.90 | 1ku | PDIP (N) | 16 | 25 | TUBE | |
CD74HC190NSR | ACTIVE | -55 to 125 | 0.90 | 1ku | SO (NS) | 16 | 2000 | LARGE T&R | |
CD74HC190NSRE4 | ACTIVE | -55 to 125 | 0.90 | 1ku | SO (NS) | 16 | 2000 | LARGE T&R | |
CD74HC190NSRG4 | ACTIVE | -55 to 125 | 0.90 | 1ku | SO (NS) | 16 | 2000 | LARGE T&R |
器件 | 环保计划* | 铅/焊球涂层 | MSL 等级/回流焊峰 | 环保信息与无铅 (Pb-free) | DPPM / MTBF / FIT 率 |
CD74HC190E | Pb-Free (RoHS) | CU NIPDAU | N/A for Pkg Type | CD74HC190E | CD74HC190E |
CD74HC190EE4 | Pb-Free (RoHS) | CU NIPDAU | N/A for Pkg Type | CD74HC190EE4 | CD74HC190EE4 |
CD74HC190NSR | Green (RoHS & no Sb/Br) | CU NIPDAU | Level-1-260C-UNLIM | CD74HC190NSR | CD74HC190NSR |
CD74HC190NSRE4 | Green (RoHS & no Sb/Br) | CU NIPDAU | Level-1-260C-UNLIM | CD74HC190NSRE4 | CD74HC190NSRE4 |
CD74HC190NSRG4 | Green (RoHS & no Sb/Br) | CU NIPDAU | Level-1-260C-UNLIM | CD74HC190NSRG4 | CD74HC190NSRG4 |