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會員注冊74HC138中文資料(功能,真值表,引腳圖)
74HC138引腳圖:
圖1 74138 引腳圖
圖2 74138功能圖
74HC138功能:
CD74HC138 ，CD74HC238和CD74HCT138 ， CD74HCT238是高速硅柵CMOS*器，適合內(nèi)存地址*或數(shù)據(jù)路由應用。74HC138 作用原理于高性能的存貯譯碼或要求傳輸延遲時間短的數(shù)據(jù)傳輸系統(tǒng),在 高性能存貯器系統(tǒng)中,用這種譯碼器可以提高譯碼系統(tǒng)的效率。將快速賦能電路用于高速存貯器時,譯碼器的延遲時間和存貯器的賦能時間通常小于存貯器的典型存取時間,這就是說由肖特基鉗位的系統(tǒng)譯碼器所引起的有效系統(tǒng)延遲可以忽略不計。HC138 按照三位二進制輸入碼和賦能輸入條件,從8 個輸出端中譯出一個 低電平輸出。兩個低電平有效的賦能輸入端和一個高電平有效的賦能輸入端減少了擴展所需要的外接門或倒相器,擴展成24 線譯碼器不需外接門;擴展成32 線譯碼器,只需要接一個外接倒相器。在解調(diào)器應用中,賦能輸入端可用作數(shù)據(jù)輸入端。
74HC138真值表:
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74HC138 74HCT138 T1TRUTH TABLE真值功能表 | |||||||||||||
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ENABLE 使能 |
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74HC238真值表:
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CD74HC238, CD74HCT238 T1TRUTH TABLE真值表 | ||||||||||||||
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INPUTS 輸入 |
Outputs輸出 | |||||||||||||
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ENABLE 使能 |
ADDRESS地址 | |||||||||||||
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E3 |
E2 |
E1 |
A2 |
A1 |
A0 |
Y0 |
Y1 |
Y2 |
Y3 |
Y4 |
Y5 |
Y6 |
Y7 | |
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