3-13
Applications
The HIN2XX may be used for all RS-232 data terminal and
communication links. It is particularly useful in applications
where
±
12V power supplies are not available for
conventional RS-232 interface circuits. The applications
presented represent typical interface configurations.
A simple duplex RS-232 port with CTS/RTS handshaking is
illustrated in Figure 9. Fixed output signals such as DTR
(data terminal ready) and DSRS (data signaling rate select)
is generated by driving them through a 5k
resistor
connected to V+.
In applications requiring four RS-232 inputs and outputs
(Figure 10), note that each circuit requires two charge pump
capacitors (C1 and C2) but can share common reservoir
capacitors (C3 and C4). The benefit of sharing common
reservoir capacitors is the elimination of two capacitors and
the reduction of the charge pump source impedance which
effectively increases the output swing of the transmitters.
-
+
-
+
-
+
DTR (20) DATA
TERMINAL READY
DSRS (24) DATA
SIGNALING RATE
SELECT
RS-232
INPUTS AND OUTPUTS
TD (2) TRANSMIT DATA
RTS (4) REQUEST TO SEND
RD (3) RECEIVE DATA
CTS (5) CLEAR TO SEND
SIGNAL GROUND (7)
15
8
13
7
14
16
-
+
6
R2
R1
T2
T1
9
12
10
11
4
5
3
1
HIN232
C1
1
μ
F
C2
1
μ
F
TD
RTS
RD
CTS
+5V
INPUTS AND
OUTPUTS
TTL/CMOS
FIGURE 9. SIMPLE DUPLEX RS-232 PORT WITH CTS/RTS
HANDSHAKING
2
FIGURE 10. COMBINING TWO HIN232s FOR 4 PAIRS OF RS-232 INPUTS AND OUTPUTS
-
+
RS-232
INPUTS AND OUTPUTS
DTR (20) DATA TERMINAL READY
DSRS (24) DATA SIGNALING RATE SELECT
DCD (8) DATA CARRIER DETECT
R1 (22) RING INDICATOR
SIGNAL GROUND (7)
15
8
13
7
14
2
-
+
4
R2
R1
T2
T1
9
12
10
11
3
1
HIN232
C1
1
μ
F
DTR
DSRS
DCD
R1
+5V
INPUTS AND
OUTPUTS
TTL/CMOS
-
+
-
+
TD (2) TRANSMIT DATA
RTS (4) REQUEST TO SEND
RD (3) RECEIVE DATA
CTS (5) CLEAR TO SEND
8
13
7
14
15
R2
R1
T2
T1
9
12
10
11
4
5
3
1
HIN232
C1
1
μ
F
C2
1
μ
F
TD
RTS
RD
CTS
INPUTS AND
OUTPUTS
TTL/CMOS
-
+
5
C2
1
μ
F
16
C3
2
μ
F
6
2
6
V-
V+
-
+C4
2
μ
F
16
HIN230 thru HIN241