Enhanced RS-232 Line Drivers and Receivers

+5V INPUT
+5V INPUT
7
7
V CC
V CC
TTL/CMOS OUTPUTS
TTL/CMOS INPUTS
T IN
1
T IN
2
R OUT
1
R OUT
2
Do not make
connection to
these pins
2 400k Ω
5
T 1
1 400k Ω
18
T 2
3 4
R 1
5kΩ
20 19
R 2
8 C +
5kΩ
1
13
C 1-
C + 11
2
14
V+
C +
15
2
12
10
V-
C 2 -
SP233ACP
16
17 V- GND GND C 2 -
T OUT
1
T OUT
2
R IN
1
R IN
2
RS-232 INPUTS
RS-232 OUTPUTS
Connect on PCB
Pin 11 to Pin 15
Pin 10 to Pin 16
Pin 12 to Pin 17
Both Pins 6 and 9 to GND
TTL/CMOS OUTPUTS
TTL/CMOS INPUTS
T IN
1
T IN
2
R OUT
1
R OUT
2
Do not make
connection to
these pins
2 400k Ω
5
T 1
1 400k Ω
18
T 2
3 4
R 1
5k Ω
20 19
R 2
13 C +
5k Ω
1
14
C 1-
C + 12
2
8
V+
C +
15
2
10
11
V-
C 2 -
SP233ACT
17
16
V- GND GND C 2 -
T OUT
1
T OUT
2
R IN
1
R IN
2
RS-232 INPUTS
RS-232 OUTPUTS
Connect on PCB
Pin 12 to Pin 15
Pin 11 to Pin 16
Pin 10 to Pin 17
Both Pins 6 and 9 to GND
6
9
6
9
Figure 2. Typical Circuits using the SP233ACP and SP233ACT
The instantaneous slew rate of the transmitter
output is internally limited to a maximum of 30V/
µs in order to meet the standards [EIA RS-232-F ].
The transition region slew rate of these enhanced
products is typically 10V/µs. The smooth transition
of the loaded output from V OL
to V OH
clearly
meets the monotonicity requirements of the standard
[EIA RS-232-F].
Receivers
The receivers convert RS-232 input signals to
inverted TTL signals. Since the input is usually
from a transmission line, where long cable lengths
and system interference can degrade the signal, the
inputs have a typical hysteresis margin of 500mV.
This ensures that the receiver is virtually immune
to noisy transmission lines.
The input thresholds are 0.8V minimum and 2.4V
maximum, again well within the ±3V RS-232
requirements. The receiver inputs are also protected
against voltages up to ±25V. Should an
input be left unconnected, a 5KΩ pulldown resistor
to ground will commit the output of the receiver
to a high state.
+5V INPUT
10 µ F 6.3V
+
+5V INPUT
10 µ F 6.3V
+
TTL/CMOS OUTPUTS
TTL/CMOS INPUTS
0.1 µ F +
6.3V
0.1 µ F +
16V
T IN
1
T IN
2
R OUT
1
R OUT
2
2
4
5
6
C +
1
C 1-
C +
2
C 2-
400k Ω
12 15
T 1
400k Ω
11 8
T 2
13 14
R 1
10 9
R 2
GND
17
V CC
V+
Charge Pump
SP310A
16
0.1 µF
10V
3 +
T OUT
1
T OUT
2
Figure 3. Typical Circuits using the SP310A and SP312A
5k Ω
5k Ω
V-
7
18
+
R IN
1
R IN
2
*
0.1 µF
10V
ON/OFF
*The negative terminal of the V+ storage capacitor can be tied
to either V CC or GND. Connecting the capacitor to V CC (+5V)
is recommended.
RS-232 INPUTS
RS-232 OUTPUTS
TTL/CMOS OUTPUTS
TTL/CMOS INPUTS
0.1 µ F +
6.3V
T IN
1
T IN
2
R OUT
1
R OUT
2
2
4
5
0.1 µ F +
16V 6
EN
C +
1
C 1-
400k Ω
12 15
T 1
400k Ω
11 8
T 2
13 14
R 1
5kΩ
10 9
R 2
1
C +
2
C 2-
GND
17
V CC
V+
Charge Pump
5kΩ
SP312A
16
V-
0.1 µ F
10V
3 +
7
18
+
0.1 µ F
10V
T OUT
1
T OUT
2
R IN
1
R IN
2
*The negative terminal of the V+ storage capacitor can be tied
to either V CC or GND. Connecting the capacitor to V CC (+5V)
is recommended.
*
RS-232 INPUTS
RS-232 OUTPUTS
SHUTDOWN
Date: 10/17/ 05 SP232A Series Enhanced RS232 Transceivers © Copyright 2005 Sipex Corporation
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