- 型号搜索
- 交叉搜索
- 关键词搜索
- 参数搜索
- 库存查询与购买
This webpage doesn't work with Internet Explorer. Please use the latest version of Google Chrome, Microsoft Edge, Mozilla Firefox or Safari.
请输入3个以上字符
The information presented in this cross reference is based on TOSHIBA's selection criteria and should be treated as a suggestion only. Please carefully review the latest versions of all relevant information on the TOSHIBA products, including without limitation data sheets and validate all operating parameters of the TOSHIBA products to ensure that the suggested TOSHIBA products are truly compatible with your design and application.Please note that this cross reference is based on TOSHIBA's estimate of compatibility with other manufacturers' products, based on other manufacturers' published data, at the time the data was collected.TOSHIBA is not responsible for any incorrect or incomplete information. Information is subject to change at any time without notice.
请输入3个以上字符
时序逻辑：计数器
计数器
示例：74VHC393，74VHC161
计数器在每个时钟（CK）脉冲上按顺序进行递增或递减计数。一个4位计数器的模数可达16；一个8位计数器的模数可达256；一个14位计数器的模数可达16384。某些计数器具有CLR输入，用于将内部状态初始化为已知值。
计数器集成在数字定时器、电子计算器、秒表和许多其它设备中。
计数器大致分为异步（纹波进位）和同步（并行进位）计数器。设单个触发器的传输延迟时间为tpd。然后，n级异步计数器将产生相当于n×tpd的大延迟。还应注意，当计数器输出馈送至逻辑门时，异步计数器可能产生风险。
74VHC393四位计数器
异步：波纹进位计数器
74VHC161四位计数器的逻辑示意图
同步：并行进位计数器
时序图：下面显示了一个典型的同步（并行进位）计数器的时序图，它在时钟（CK）的每一个边沿上按顺序进行递增计数。
