74LS138 為3 線-8線解碼器,共有 54LS138和 74LS138 兩種線路結構型式。54LS138為軍用,74LS138為民用。
基本介紹
- 中文名:74LS138
- 別名:三八解碼器
- 本質:3 線-8 線解碼器
- 結構型式:54LS138和 74LS138
- A0~A2:地址輸入端
- STA(E1):選通端
- 輸入:二進制形式
工作原理
引腳功能

內部邏輯圖

真值表
輸入 | 輸出 | ||||||||||||
G1 | /G2A | /G2B | A2 | A1 | A0 | /Y0 | /Y1 | /Y2 | /Y3 | /Y4 | /Y5 | /Y6 | /Y7 |
× | 1 | × | × | × | × | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
× | × | 1 | × | × | × | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
0 | × | × | × | × | × | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
1 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
1 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 |
1 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 |
1 | 0 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |
1 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 |
1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |