2
引脚
cd54hc240, cd54hct240, cd54hct241,
cd54hc244, cd54hct244
(cerdip)
cd74hc240, cd74hc241, cd74hct241,
cd74hc244, cd74hct244
(pdip, soic)
cd74hct240,
(pdip, soic, tssop)
顶 视图
函数的 图解
11
12
13
14
15
16
17
18
20
19
10
9
8
7
6
5
4
3
2
1
1OE
1A0
2Y3
1A1
2Y2
1A2
1A3
2Y1
2Y0
地
V
CC
1Y0
2A3
1Y1
2oe (241)
2A2
1Y2
2A1
1Y3
2A0
241
244 240
V
CC
1Y0
2A3
1Y1
2oe (240, 244)
2A2
1Y2
2A1
1Y3
2A0
1OE
1A0
2Y3
1A1
2Y2
1A2
1A3
2Y1
2Y0
地
241
244240
18
16
14
12
7
3
5
9
2
1Y0
1Y1
1Y2
1Y3
2Y0
2Y1
2Y2
2Y3
2OE
1OE
1
19
6
2OE
1OE
1Y0
1Y1
1Y2
1Y3
2Y0
2Y1
2Y2
2Y3
240
241
17
4
8
11
13
15
1A0
1A1
1A2
1A3
2A0
2A1
2A2
2A3
240
和
244
241
和
244
V
CC
= 20
地 = 10
cd54/74hc240, cd54/74hct240, cd74hc241, cd54/74hct241, cd54/74hc244, cd54/74hct244