5 V-Powered
CMOS RS-232 Drivers/Receivers
ADM231L–ADM234L/ADM236L–ADM241L
FEATURES
ADM236L TYPICAL OPERATING CIRCUIT
Single 5 V power supply
Meets all EIA-232-E and V.28 specifications
120 kbps data rate
On-board dc-to-dc converters
±9 V output swing with 5 V supply
Small 1 µF capacitors
Low power shutdown ≤1 µA
±30 V receiver input levels
Latch-up free
+5V INPUT
1µF
+6.3V
1µF
+16V
C1+
C1–
C2+
C2–
+5V TO +10V
VOLTAGE
DOUBLER
+10V TO –10V
VOLTAGE
INVERTER
VCC
V+
1µF
+6.3V
V–
1µF
+16V
T1IN
Computers
Peripherals
Modems
Printers
Instruments
T1OUT
T2
T2OUT
T3IN
T3
T3OUT
T4IN
APPLICATIONS
T1
T2IN
TTL/CMOS
INPUTS1
T4
T4OUT
R1OUT
R1
R2OUT
R2
R2IN
R3
R3IN
ADM236L
RS-232
OUTPUTS
R1IN
R3OUT
TTL/CMOS
OUTPUTS
1µF
+6.3V
SD
RS-232
INPUTS2
EN
The ADM2xx family of line drivers/receivers is intended for all
EIA-232-E and V.28 communications interfaces, especially in
applications in which 12 V is not available. The ADM236L and
ADM241L feature a low power shutdown mode that reduces
power dissipation to less than 5 µW, making them ideally suited
for battery-powered equipment. The ADM233L does not
require any external components and is particularly useful in
applications where printed circuit board space is critical.
All members of the ADM2xxL family, except the ADM231L and
ADM239L, include two internal charge pump voltage converters
that allow operation from a single 5 V supply. These parts convert
the 5 V input power to the ±10 V required for RS-232 output
GND
1INTERNAL 400kΩ PULL-UP RESISTOR ON EACH TTL/CMOS INPUT.
2INTERNAL 5kΩ PULL-DOWN RESISTOR ON EACH RS-232 INPUT.
Figure 1.
levels. The ADM231L and ADM239L are designed to operate
from 5 V and 12 V supplies. An internal +12 V to −12 V charge
pump voltage converter generates the −12 V supply.
The ADM2xxL is an enhanced upgrade to the AD2xx family. It
features lower power consumption, faster slew rate, and the
ability to operate with smaller (1 µF) capacitors.
Table 1. Selection Table
Part
Number
ADM231L
ADM232L
ADM233L
ADM234L
ADM236L
ADM237L
ADM238L
ADM239L
ADM241L
Power Supply Voltage
5 V and 7.5 V to 13.2 V
5V
5V
5V
5V
5V
5V
5 V and 7.5 V to 13.2 V
5V
No. of RS-232
Drivers
2
2
2
4
4
5
4
3
4
No. of RS-232
Receivers
2
2
2
0
3
3
4
5
5
External
Capacitors
2
4
None
4
4
4
4
2
4
Low Power
Shutdown (SD)
No
No
No
No
Yes
No
No
No
Yes
TTL
Three-State EN
No
No
No
No
Yes
No
No
Yes
Yes
No. of
Pins
14
16
20
16
24
24
24
24
28
Rev. C
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© 2005 Analog Devices, Inc. All rights reserved.
00070-0-015
GENERAL DESCRIPTION
