论文部分内容阅读
74ALS/AS系列IC,是继74、74L、74H第一代,74LS、74S第二代,由德克萨斯仪器公司研制的第三代TTL数字IC.以74打头是民用,54打头是军用品,除了使用温度不同外,其它特性完全相同.ALS的A是英文“Advanced”的缩写,即先进的LS、S电路.ALS系列IC,比LS系列速度更高、功耗更小;同样,AS系列比S系列也更快、功耗更低.此外ALS、AS系列IC,驱动能力大幅度改善,扇出也大大增加.本文首先分析其直流及交流特性,然后说明使用ALS、AS系列IC,在系统设计中应注意的问题.
74ALS / AS Series IC, is the second generation of 74,74L, 74H, 74LS, 74S second-generation, developed by Texas Instruments third-generation TTL digital IC. Supplies, in addition to the use of different temperatures, the other characteristics are exactly the same. AALS is the abbreviation of the English “Advanced”, that is, advanced LS, S. Circuit series ASIC, LS series faster and consume less power; AS series also faster than the S series, lower power consumption.In addition, ALS, AS series IC, a substantial improvement in drive capability, fan-out is also greatly increased.This paper first analyzes the DC and AC characteristics, and then shows the use of ALS, AS series IC , The system design should pay attention to the problem.