+3V to +5.5V RS-232 Transceivers
with AutoShutdown
MAX3221/MAX3223/MAX3243
Typical Operating Circuits
+3.3V
15
0.1μF
C5
V
CC
3
7
2
C1+
V+
V-
C1
C3
0.1μF
4
5
6
0.1μF
+3.3V
C1-
C2+
MAX3221
26
0.1μF
C4
0.1μF
V
CC
C2
0.1μF
27
3
28
C1+
V+
C1
C2-
C3
0.1μF
0.1μF
24
1
C1-
C2+
11
9
T1IN
T1OUT 13
MAX3243
V-
C4
0.1μF
C2
0.1μF
2
R1OUT
R1IN
5kΩ
8
C2-
T1IN
T1OUT
9
14
RS-232
OUTPUTS
T2IN
T3IN
LOGIC
INPUTS
T2OUT 10
13
12
TO POWER
MANAGEMENT
UNIT
EN
INVALID 10
1
11
T3OUT
FORCEOFF
FORCEON
16
12
V
CC
GND
14
R2OUTB
R1OUT
20
19
R1IN
4
5
5kΩ
+3.3V
19
R2OUT
R3OUT
R4OUT
R2IN
18
17
16
0.1μF
C5
V
CC
3
2
5kΩ
C1+
V+
V-
LOGIC
OUTPUTS
C1
0.1μF
C3
0.1μF
4
5
6
6
7
8
R3IN
RS-232
INPUTS
C1-
C2+
MAX3223
7
5kΩ
C4
0.1μF
C2
0.1μF
R4IN
C2-
13
T1IN
T1OUT 17
5kΩ
TTL/CMOS
INPUTS
RS-232
OUTPUTS
R5OUT
15
23
R5IN
8
T2IN
T2OUT
12
5kΩ
FORCEON
FORCEOFF
INVALID
16
15 R1OUT
R1IN
22
21
V
CC
TTL/CMOS
OUTPUTS
RS-232
INPUTS
5kΩ
TO POWER
MANAGEMENT UNIT
GND
25
R2IN
10 R2OUT
9
5kΩ
TO POWER
MANAGEMENT
UNIT
EN
INVALID 11
1
FORCEOFF
FORCEON
20
14
V
CC
GND
18
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