+ 5V供电，多通道RS - 232
驱动器/接收器
MAX220–MAX249
顶视图
1F
21
T
A3
OUT
T
A2
OUT
T
A1
OUT
T
B1
OUT
T
B2
OUT
T
B3
OUT
R
A3
IN
R
A4
IN
R
A5
IN
R
B5
IN
R
B4
IN
1F
1F
20
V
CC
+ 5V至+ 10V电压DOUBLER
+ 10V至-10V的电压逆变器
ENTB 27
+5V
1 T
A1
OUT
R
A2
IN
R
A1
IN
ENRA
R
A1
OUT
R
A2
OUT
R
A3
OUT
R
A4
OUT
R
A5
OUT
T
A1
IN
T
A2
IN
T
A3
IN
7
8
9
10
11
12
13
14
15
16
17
18
19 20 21 22 23 24 25 26 27 28
39
R
B3
IN
38
R
B2
IN
37
R
B1
IN
36
ENRB
+5V
1F
6
5
4
3
2
1
44 43 42 41 40
C1+
23 C1-
24
C2+
25 C2-
18 ENTA
V+
V-
22
26
1F
+5V
T
B1
OUT 44
400k
T
B1
在30
15 T
A1
IN
+5V
2 T
A2
OUT
400k
16 T
A2
IN
+5V
3 T
A3
OUT
400k
17 T
A3
IN
8 R
A1
IN
5k
10 R
A1
OUT
7 R
A2
IN
5k
11 R
A2
OUT
6 R
A3
IN
5k
12 R
A3
OUT
5 R
A4
IN
5k
13 R
A4
OUT
4 R
A5
IN
5k
14 R
A5
OUT
9 ENRA
GND
19
5k
5k
5k
5k
5k
+5V
+5V
T
B2
OUT 43
T
B2
29
T
B3
OUT 42
T
B3
28
R
B1
37
MAX249
35
R
B1
OUT
34
R
B2
OUT
33
R
B3
OUT
32
R
B4
OUT
31
R
B5
OUT
30
T
B1
IN
29
T
B2
IN
C1-
C2-
T
B3
IN
ENTA
C1+
C2+
ENTB
GND
V+
V
CC
V-
R
B1
出35
R
B2
38
PLCC
MAX249功能说明
10个接收器
5人制接收机
5 B - SIDE接收机
6变送器
3人制变送器
3 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 ）
启用收件人B- SIDE （ ENTB ）
R
B2
出34
R
B3
39
R
B3
OUT 33
R
B4
40
R
B4
OUT 32
R
B5
41
R
B5
OUT 31
ENRB 36
图25. MAX249引脚配置和典型工作电路
34
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