a
FEATURES
200 kB/s Transmission Rate
Small (0.1 F) Charge Pump Capacitors
Single 5 V Power Supply
Meets All 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
30 V Receiver Input Levels
Pin Compatible with MAX222/MAX232A/MAX242
APPLICATIONS
Computers
Peripherals
Modems
Printers
Instruments
High-Speed, 5 V, 0.1 F
CMOS RS-232 Drivers/Receivers
ADM222/ADM232A/ADM242
FUNCTIONAL BLOCK DIAGRAM
5V INPUT
0.1 F
V
CC
+5V TO +10V
V+
VOLTAGE DOUBLER
+5V TO –10V
VOLTAGE INVERTER V–
0.1 F
0.1 F
C1+
0.1 F
C1–
C2+
0.1 F
C2–
T1
IN
TTL/CMOS
INPUTS
*
T2
IN
R1
OUT
TTL/CMOS
OUTPUTS
R2
OUT
T1
T2
R1
R2
T1
OUT
T2
OUT
R1
IN
R2
IN
EN
SHDN
RS-232
INPUTS
**
RS-232
OUTPUTS
ADM2xx
(ADM242)
(ADM222, ADM242)
GENERAL DESCRIPTION
GND
The ADM222, ADM232A, ADM242 are a family of high-speed
RS-232 line drivers/receivers offering transmission rates up to
200 kB/s. Operating from a single 5 V power supply, a highly
efficient on-chip charge pump using small (0.1
µF)
external
capacitors allows RS-232 bipolar levels to be developed. Two
RS-232 drivers and two RS-232 receivers are provided on
each device.
The devices are fabricated on BiCMOS, an advanced mixed
technology process that combines low power CMOS with high-
speed bipolar circuitry. This allows for transmission rates up to
200 kB/s, yet minimizes the quiescent power supply current to
under 5 mA.
The ADM232A is a pin-compatible, high-speed upgrade for the
AD232 and for the ADM232L. It is available in 16-lead DIP
and in both narrow and wide surface-mount (SOIC) packages.
The ADM222 contains an additional shutdown (SHDN) func-
tion that may be used to disable the device, thereby reducing the
supply current to 0.1
µA.
During shutdown, all transmit/receive
PULL-UP RESISTOR
ON EACH TTL/CMOS INPUT
**
INTERNAL 5k PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
*
INTERNAL 400k
functions are disabled. The ADM222 is available in 18-lead
DIP and in a wide surface-mount (SOIC) package.
The ADM242 combines both shutdown (SHDN) and enable
(EN) functions. The shutdown function reduces the supply
current to 0.1 mA. During shutdown, the transmitters are dis-
abled but the receivers continue to operate normally. The
enable function allows the receiver outputs to be disabled
thereby facilitating sharing a common bus. The ADM242 is
available in 18-lead DIP and in a wide surface-mount (SOIC)
package.
REV.
C
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ADM222/ADM232A/ADM242–SPECIFICATIONS
Parameter
RS-232 TRANSMITTERS
Output Voltage Swing
Input Logic Threshold Low, V
INL
Input Logic Threshold High, V
INH
Logic Pull-Up Current
Data Rate
Output Resistance
Output Short Circuit Current (Instantaneous)
RS-232 RECEIVERS
RS-232 Input Voltage Range
RS-232 Input Threshold Low
RS-232 Input Threshold High
RS-232 Input Hysteresis
RS-232 Input Resistance
TTL/CMOS Output Voltage Low, V
OL
TTL/CMOS Output Voltage High, V
OH
TTL/CMOS Output Short-Circuit Current
TTL/CMOS Output Short-Circuit Current
TTL/CMOS Output Leakage Current
EN
Input Threshold Low, V
INL
EN
Input Threshold High, V
INH
POWER SUPPLY
Power Supply Current
Shutdown Power Supply Current
SHDN
Input Leakage Current
SHDN
Input Threshold Low, V
INL
SHDN
Input Threshold High, V
INH
AC CHARACTERISTICS
Transition Region Slew Rate
Transmitter Propagation Delay TTL to RS-232
Receiver Propagation Delay RS-232 to TTL
Receiver Output Enable Time
Receiver Output Disable Time
Transmitter Output Enable Time
Transmitter Output Disable Time
Transmitter + to – Propagation Delay Difference
Receiver + to – Propagation Delay Difference
*Guaranteed
by design, not production tested.
Specifications subject to change without notice.
(V
CC
= 5 V 10%. C1–C4 = 0.1 F; all spec-
ifications T
MIN
to T
MAX
unless otherwise noted.)
Min
±
5
2.4
200
300
Typ
±
9
1.7
1.7
12
±
10
Max
Unit
V
Test Conditions/Comments
All Transmitter Outputs Loaded with
3 kΩ to Ground
T
IN
T
IN
T
IN
= 0 V
V
CC
= V+ = V– = 0 V, V
OUT
=
±
2 V
0.8
40
V
V
µA
kB/s
Ω
mA
V
V
V
V
kΩ
V
V
mA
mA
µA
V
V
mA
mA
µA
µA
V
V
V/µs
µs
µs
µs
µs
ns
ns
µs
µs
ns
ns
–30
0.8
0.2
3
3.5
–2
10
+30
1.2
1.6
0.4
5
0.05
–85
35
±
0.05
1.4
1.4
4
13
0.1
1.4
1.4
8
0.85
1.0
0.1
0.3
125
160
250
3.5
150
200
2.4
1.0
7
0.4
±
10
0.8
V
CC
= 5 V
T
A
= 0°C to 85°C
I
OUT
= 3.2 mA
I
OUT
= –1.0 mA
Source Current (V
OUT
= GND)*
Sink Current (V
OUT
= V
CC
)*
SHDN
= GND/EN = V
CC
0 V
≤
V
OUT
≤
V
CC
2.0
8
10
±
1
0.8
No Load
3 kΩ Load on Both Outputs
2.0
3
30
3.5
3.5
0.5
0.5
500
500
C
L
= 50 pF to 1000 pF, R
L
= 3 kΩ to 7 kΩ
Measured from +3 V to –3 V or –3 V to +3 V
t
PHLT
t
PLHT
t
PHLR
t
PLHR
t
ER
t
DR
SHDN
Goes High
SHDN
Goes Low
–2–
REV.
C
ADM222/ADM232A/ADM242
ABSOLUTE MAXIMUM RATINGS*
(T
A
= 25°C unless otherwise noted)
V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 V
V+ . . . . . . . . . . . . . . . . . . . . . . . . . . . (V
CC
– 0.3 V) to +13 V
V– . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V to –13 V
Input Voltages
T
IN
. . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to (V
CC
+ 0.3 V)
R
IN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±
30 V
Output Voltages
T
OUT
. . . . . . . . . . . . . . . . . . . (V+, +0.3 V) to (V–, –0.3 V)
R
OUT
. . . . . . . . . . . . . . . . . . . . . . . –0.3 V to (V
CC
+ 0.3 V)
Short Circuit Duration
T
OUT
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous
Power Dissipation N-16 . . . . . . . . . . . . . . . . . . . . . . 400 mW
(Derate 7.5 mW/°C above 70°C)
θ
JA
, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80°C/W
Power Dissipation R-16N . . . . . . . . . . . . . . . . . . . . . 400 mW
(Derate 7 mW/°C above 70°C)
θ
JA
, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80°C/W
Power Dissipation R-16W . . . . . . . . . . . . . . . . . . . . . 400 mW
(Derate 7 mW/°C above 70°C)
θ
JA
, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80°CW
Power Dissipation N-18 . . . . . . . . . . . . . . . . . . . . . . 400 mW
(Derate 7 mW/°C above 70°C)
θ
JA
, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80°C/W
Power Dissipation R-18W . . . . . . . . . . . . . . . . . . . . . 400 mW
(Derate 7 mW/°C above 70°C)
θ
JA
, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 80°C/W
Operating Temperature Range
Industrial (A Version) . . . . . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . 300°C
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
*This
is a stress rating only and functional operation of the device at these or any
other conditions above those indicated in the operation sections of this specifica-
tion is not implied. Exposure to absolute maximum rating conditions for extended
periods of time may affect reliability.
Test Circuits
3V
3V
V
IN
V
IN
0V
t
PLHT
V
OUT
t
PHLT
V+
0V
V–
t
PHLR
t
PLHR
V
CC
V
OUT
50%
GND
Figure 1. Transmitter Propagation Delay Timing
Figure 3. Receiver Propagation Delay Timing
3V
3V
EN
INPUT
EN
INPUT
0V
0V
t
DR
t
ER
3.5V
RECEIVER
OUTPUT
0.8V
V
OH
V
OH
–
0.5V
RECEIVER
OUTPUT
V
OL
+ 0.5V
V
OL
Figure 2. Receiver Enable Timing
Figure 4. Receiver Disable Timing
REV.
C
–3–
ADM222/ADM232A/ADM242
V
IN
3k
SHDN
50pF
V
OUT
PIN FUNCTION DESCRIPTION
Mnemonic
V
CC
V+
Function
Power Supply Input, 5 V
±
10%.
Internally generated positive supply (+10 V
nominal).
Internally generated negative supply (–10 V
nominal).
Ground Pin. Must be connected to 0 V.
External capacitor 1, (+ terminal) is connected
to this pin.
External capacitor 1, (– terminal) is connected
to this pin.
External capacitor 2, (+ terminal) is connected
to this pin.
External capacitor 2, (– terminal) is connected
to this pin.
Transmitter (Driver) Inputs. These inputs accept
TTL/CMOS levels. An internal 400 kΩ pull-up
resistor to V
CC
is connected on each input.
Transmitter (Driver) Outputs. These are RS-232
levels (typically
±
9 V).
Receiver Inputs. These inputs accept RS-232
signal levels. An internal 5 kΩ pull-down resistor
to GND is connected on each of these inputs.
Receiver Outputs. These are TTL/CMOS levels.
No Connect. No connections are required to
this pin.
(ADM242 Only) Active Low Digital Input. May
be used to enable or disable (three-state) both
receiver outputs.
(ADM222 and ADM242) Active Low Digital
Input. May be used to disable the device so that
the power consumption is minimized. On the
ADM222 all drivers and receivers are disabled.
On the ADM242 the drivers are disabled but the
receivers remain enabled.
Figure 5. Shutdown Test Circuit
3V
SHDN
INPUT
0V
V–
GND
C1+
C1–
t
DT
C2+
C2–
+ 5V
V+
T
IN
TRANSMITTER
OUTPUT
–
5V
V–
T
OUT
R
IN
Figure 6. Transmitter Shutdown Disable Timing
R
OUT
NC
5V INPUT
C5
0.1 F
6.3V
2
C1
0.1 F
EN
17
C3
0.1 F
C2
0.1 F
V
CC
C1+
3
+5V TO +10V
V+
VOLTAGE DOUBLER
4
C1–
5
C2+
+5V TO
–10V
7
VOLTAGE INVERTER V–
6
C2–
12
11
T2
13
R1
10
R2
15
8
14
9
SHDN
C4
0.1 F
T1
OUT
T2
OUT
R1
IN
R2
IN
SHDN
RS-232
INPUTS
**
RS-232
OUTPUTS
T1
IN
TTL/CMOS
INPUTS
*
T2
IN
R1
OUT
TTL/CMOS
OUTPUTS
R2
OUT
T1
NC
1
C1+
2
V+
3
C1–
4
C2+
5
18
17
16
SHDN
V
CC
GND
T1
OUT
ADM222
GND
16
ADM222
15
18
TOP VIEW
14
R1
IN
(Not to Scale)
C2–
6
13
R1
OUT
V–
7
12
11
10
PULL-UP RESISTOR
ON EACH TTL/CMOS INPUT
**
INTERNAL 5k PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
*
INTERNAL 400k
T1
IN
T2
IN
R2
OUT
T2
OUT 8
R2
IN 9
NC = NO CONNECT
Figure 7. ADM222 Typical Operating Circuit
Figure 8. ADM222 DIP and SOIC Pin Configurations
–4–
REV.
C
ADM222/ADM232A/ADM242
EN
1
18
SHDN
17
V
CC
16
GND
C1+
1
V+
2
C1–
3
C2+
4
16
V
CC
15
GND
14
T1
OUT
C1+
2
V+
3
C1–
4
C2+
5
ADM242
15
T1
OUT
13
R1
IN
TOP VIEW
C2–
5
(Not to Scale)
12
R1
OUT
ADM232A
TOP VIEW
14
R1
IN
(Not to Scale)
C2–
6
13
R1
OUT
V–
7
12
T1
IN
11
T2
IN
10
R2
OUT
V–
6
T2
OUT 7
R2
IN 8
11
T1
IN
10
T2
IN
9
T2
OUT 8
R2
IN 9
R2
OUT
Figure 9. ADM232A DIP/SOIC Pin Configuration
Figure 11. ADM242 DIP/SOIC Pin Configuration
5V INPUT
C5
0.1 F
6.3V
C5
0.1 F
6.3V
C3
0.1 F
C1
0.1 F
2
5V INPUT
C1
0.1 F
C2
0.1 F
16
V
CC
C1+
2
+5V TO +10V
V+
VOLTAGE DOUBLER
3
C1–
4
C2+
+5V TO
–10V
6
VOLTAGE INVERTER V–
5
C2–
1
11
10
T2
12
R1
9
R2
14
7
13
8
17
C4
0.1 F
T1
OUT
T2
OUT
R1
IN
R2
IN
RS-232
INPUTS
**
TTL/CMOS
OUTPUTS
RS-232
OUTPUTS
TTL/CMOS
INPUTS
*
C2
0.1 F
V
CC
C1+
3
+5V TO +10V
V+
VOLTAGE DOUBLER
4
C1–
5
C2+
+5V TO
–10V
7
VOLTAGE INVERTER V–
6
C2–
12
11
T2
13
R1
10
1
GND
9
R2
15
C3
0.1 F
C4
0.1 F
T1
OUT
T2
OUT
R1
IN
R2
IN
RS-232
INPUTS
**
RS-232
OUTPUTS
T1
IN
TTL/CMOS
INPUTS
*
T2
IN
R1
OUT
TTL/CMOS
OUTPUTS
R2
OUT
T1
T1
IN
T2
IN
R1
OUT
R2
OUT
EN
T1
8
14
ADM232A
GND
15
PULL-UP RESISTOR
ON EACH TTL/CMOS INPUT
**
INTERNAL 5k PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
ADM242
16
18
SHDN
*
INTERNAL 400k
PULL-UP RESISTOR
ON EACH TTL/CMOS INPUT
**
INTERNAL 5k PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
*
INTERNAL 400k
Figure 10. ADM232A Typical Operating Circuit
Figure 12. ADM242 Typical Operating Circuit
REV.
C
–5–
