+ 5V供电，多通道RS - 232
驱动器/接收器
MAX220–MAX249
+5V
顶视图
1F
40
V
CC
+5V
+5V
400k
2 T
A1
IN
+5V
17 T
A2
OUT
400k
3 T
A2
IN
+5V
18 T
A3
OUT
400k
4 T
A3
IN
+5V
19 T
A4
OUT
400k
5 T
A4
IN
6 R
B5
OUT
T
B4
35
R
B5
在25
5k
+5V
T
B4
OUT 21
T
B3
36
+5V
T
B3
OUT 22
T
B2
37
+5V
T
B2
OUT 23
T
B1
38
1 ENTA
ENTA
T
A1
IN
T
A2
IN
T
A3
IN
T
A4
IN
R
B5
OUT
R
A4
OUT
R
A3
OUT
R
A2
OUT
R
A1
OUT
ENRA
R
A1
IN
R
A2
IN
R
A3
IN
R
A4
IN
T
A1
OUT
T
A2
OUT
T
A3
OUT
T
A4
OUT
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
V
CC
ENTB
T
B1
IN
T
B2
IN
T
B3
IN
T
B4
IN
R
B4
OUT
R
B3
OUT
R
B2
OUT
R
B1
OUT
ENRB
R
B1
IN
R
B2
IN
R
B3
IN
R
B4
IN
R
B5
IN
T
B1
OUT
T
B2
OUT
T
B3
OUT
T
B4
OUT
10 R
A1
OUT
13 R
A2
IN
12 R
A1
IN
5k
16 T
A1
OUT
ENTB 39
T
B1
出24
MAX247
34
33
32
31
30
29
28
27
26
25
24
23
22
21
R
B1
29
5k
R
B1
OUT 31
R
B2
28
5k
R
B2
OUT 32
R
B3
27
5k
R
B3
OUT 33
R
B4
26
5k
R
B4
出34
ENRB 30
GND
20
DIP
5k
MAX247功能说明
9接收机
4 A- SIDE接收机
5 B - SIDE容器（ RB5始终处于激活状态）
8变送器
4人制变送器
4 B- SIDE变送器
4控制引脚
ENABLE接收器端（ ENRA ）
启用收件人B- SIDE （ ENRB ）
ENABLE接收器端（ ENTA ）
ENABLE RECEIVERr B- SIDE （ ENTB ）
9 R
A2
OUT
14 R
A3
IN
5k
8 R
A3
OUT
15 R
A4
IN
5k
7 R
A4
OUT
11 ENRA
图23. MAX247引脚配置和典型工作电路
32
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