+5V-Powered, Multichannel RS-232
Drivers/Receivers
TOP VIEW
+5V
1µF
1µF
20
21
C1+
C1-
V
22
CC
V+
V-
1µF
1µF
23
24
+5V TO +10V VOLTAGE DOUBLER
26
C2+
C2-
1µF
43
42 41 40
6
5
4
3
2
1
44
25
+10V TO -10V VOLTAGE INVERTER
18 ENTA
ENTB 27
+5V
+5V
+5V
1 T OUT
A1
T
T
T
T
OUT 44
B1
T
R
R
IN
IN
7
8
9
39
38
37
R
R
R
IN
IN
IN
A2
B3
B2
B1
400kΩ
14 T IN
A1
IN 31
B1
A1
ENRA
+5V
2 T OUT
A2
OUT 43
R
R
R
R
OUT 10
OUT 11
OUT 12
OUT 13
36 ENRB
B2
T
A1
A2
A3
400kΩ
35
34
33
32
31
30
29
R
R
R
R
OUT
OUT
OUT
OUT
B1
B2
B3
B4
MAX248
15 T IN
IN 30
B2
A2
+5V
+5V
A4
T
3 T OUT
OUT 42
A3
B3
T
IN 14
IN 15
IN 16
IN 17
A1
A2
A3
A4
400kΩ
T
T
T
T
IN
IN
IN
B1
B2
B3
16 T IN
IN 29
B3
A3
T
T
+5V
400kΩ
+5V
4 T OUT
OUT 41
A4
B4
T
18 19 20 21 22 23 24 25 26 27 28
17 T IN
IN 28
IN 37
A4
B4
B1
8 R IN
R
A1
PLCC
5kΩ
5kΩ
10 R OUT
A1
R
OUT 35
B1
MAX248 FUNCTIONAL DESCRIPTION
8 RECEIVERS
7 R IN
A2
R
IN 38
B2
4 A-SIDE RECEIVERS
5kΩ
11 R OUT
5kΩ
4 B-SIDE RECEIVERS
8 TRANSMITTERS
R
OUT 34
A2
B2
R
4 A-SIDE TRANSMITTERS
4 B-SIDE TRANSMITTERS
4 CONTROL PINS
6 R IN
IN 39
B3
A3
5kΩ
12 R OUT
5kΩ
ENABLE RECEIVER A-SIDE (ENRA)
ENABLE RECEIVER B-SIDE (ENRB)
ENABLE RECEIVER A-SIDE (ENTA)
ENABLE RECEIVER B-SIDE (ENTB)
R
OUT 33
A3
B3
R
5 R IN
IN 40
B4
A4
5kΩ
5kΩ
13 R OUT
A4
R OUT 32
B4
9 ENRA
ENRB 36
GND
19
Figure 24. MAX248 Pin Configuration and Typical Operating Circuit
______________________________________________________________________________________ 33
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
