74HC138中文资料(功能,真值表,引脚图)
74HC138引脚图:
图1 74138 引脚图
图2 74138功能图
74HC138功能:
CD74HC138 ，CD74HC238和CD74HCT138 ， CD74HCT238是高速硅栅CMOS*器，适合内存地址*或数据路由应用。74HC138 作用原理于高性能的存贮译码或要求传输延迟时间短的数据传输系统,在高性能存贮器系统中,用这种译码器可以提高译码系统的效率。将快速赋能电路用于高速存贮器时,译码器的延迟时间和存贮器的赋能时间通常小于存贮器的典型存取时间,这就是说由肖特基钳位的系统译码器所引起的有效系统延迟可以忽略不计。HC138 按照三位二进制输入码和赋能输入条件,从8 个输出端中译出一个 低电平输出。两个低电平有效的赋能输入端和一个高电平有效的赋能输入端减少了扩展所需要的外接门或倒相器,扩展成24 线译码器不需外接门;扩展成32 线译码器,只需要接一个外接倒相器。在解调器应用中,赋能输入端可用作数据输入端。
74HC138真值表:
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74HC138 74HCT138 T1TRUTH TABLE真值功能表 | |||||||||||||
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74HC238真值表:
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CD74HC238, CD74HCT238 T1TRUTH TABLE真值表 | ||||||||||||||
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INPUTS 输入 |
Outputs输出 | |||||||||||||
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ENABLE 使能 |
ADDRESS地址 | |||||||||||||
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E3 |
E2 |
E1 |
A2 |
A1 |
A0 |
Y0 |
Y1 |
Y2 |
Y3 |
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