High Speed, +5 V, 0.1 F
CMOS RS-232 Driver/Receivers
a
ADM202/ADM203
FUNCTIONAL BLOCK DIAGRAMS
FEATURES
120 kB Transmission Rate
ADM202: Small (0.1 F) Charge Pump Capacitors
ADM203: No External Capacitors Required
Single 5 V Power Supply
Meets EIA-232-E and V.28 Specifications
Two Drivers and Two Receivers
On-Board DC-DC Converters
؎9 V Output Swing with +5 V Supply
Low Power BiCMOS: 2.0 mA ICC
؎30 V Receiver Input Levels
+5V INPUT
0.1µF
6.3V
C1+
C1–
C2+
1
3
V
16
2
+5V TO +10V
VOLTAGE
DOUBLER
CC
0.1µF
6.3V
0.1µF
6.3V
V+
4
5
+10V TO –10V
VOLTAGE
INVERTER
V–
0.1µF
16V
6
0.1µF
16V
C2–
11
10
14
7
T1
T2
T1
T2
R1
T1
IN
OUT
TTL/CMOS
INPUTS
RS-232
OUTPUTS
APPLICATIONS
Computers
Peripherals
Modems
Printers
Instruments
*
T2
IN
OUT
12
9
R1
R1
13
8
OUT
IN
IN
RS-232
INPUTS**
TTL/CMOS
OUTPUTS
R2
R2
R2
OUT
GND
15
ADM202
+5V INPUT
GENERAL DESCRIPTION
7
The ADM202/ADM203 is a two-channel RS-232 line driver/
receiver pair designed to operate from a single +5 V power sup-
ply. A highly efficient on-chip charge pump design permits
RS-232 levels to be developed using charge pump capacitors as
small as 0.1 µF. The capacitors are internal to the package on
the ADM203 so no external capacitors are required. These con-
verters generate ±10 V RS-232 output levels.
V
CC
2
1
5
T1
T1
T2
T1
T2
IN
OUT
TTL/CMOS
RS-232
OUTPUTS
INPUTS
*
18
T2
IN
OUT
R1
R1
R1
4
3
OUT
IN
IN
RS-232
INPUTS**
TTL/CMOS
OUTPUTS
R2
20
19
R2
R2
OUT
The ADM202/ADM203 meets or exceeds the EIA-232-E and
V.28 specifications. Fast driver slew rates permit operation up to
120 kB while high drive currents allows for extended cable
lengths.
DO NOT MAKE
CONNECTIONS TO
THESE PINS
8
C1+
11
15
10
16
C2+
C2+
C1–
V–
13
12
INTERNAL
–10V POWER
SUPPLY
An epitaxial BiCMOS construction minimizes power consump-
tion to 10 mW and also guards against latch-up. Overvoltage
protection is provided allowing the receiver inputs to withstand
continuous voltages in excess of ±30 V. In addition, all pins
contain ESD protection to levels greater than 2 kV.
C2–
C2–
ADM203
V–
17
14
INTERNAL
+10V POWER
SUPPLY
V+
GND
6
GND
9
The ADM202 is available in 16-lead DIP and both narrow and
wide SOIC packages. The ADM203 is available in a 20-pin DIP
package.
*
INTERNAL 400k PULL-UP RESISTOR ON EACH TTL/CMOS INPUT
**INTERNAL 5k PULL-DOWN RESISTOR ON EACH RS-232 INPUT
REV. 0
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reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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