±15 kV ESD Protected, 3.3 V, RS-232
Line Driver/Receiver
ADM3232E
Rev. B
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
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Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©2006–2011 Analog Devices, Inc. All rights reserved.
FEATURES
Data rate: 460 kbps
2 Tx and 2 Rx
Meets EIA-232E specifications
0.1 μF charge pump capacitors
ESD protection to IEC 1000-4-2 (801.2) on RS-232 I/Os
Contact discharge: ±8 kV
Air gap discharge: ±15 kV
APPLICATIONS
General-purpose RS-232 data link
Portable instruments
Handsets
Industrial/telecom diagnostic ports
FUNCTIONAL BLOCK DIAGRAM
C1+
C2+
C1–
C2–
V
CC
V–
V+
T1
IN
T1
OUT
T2
IN
T2
OUT
R1
OUT
R1
IN
R2
OUT
R2
IN
TTL/CMOS
INPUTS RS-232
OUTPUTS
TTL/CMOS
OUTPUTS
RS-232
INPUTS*
T1
T2
R1
R2
+
+
+
C1
0.1µF
10V
C2
0.1µF
10V
GND
ADM3232E
C3
0.1µF
6.3V
+3.3V INPU
T
+3.3V TO +6.6V
VOLTAGE
DOUBLER
+6.6V TO –6.6V
VOLTAGE
INVERTER
C5
0.1µF
+
C4
0.1µF
10V
+
*INTERNAL 5kΩ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT.
5kΩ
5kΩ
06410-001
Figure 1.
GENERAL DESCRIPTION
The ADM3232E transceiver is a high speed, 2-channel RS-232/V.28
interface device that operates from a single 3.3 V power supply.
Low power consumption makes it ideal for battery-powered
portable instruments. The ADM3232E conforms to the EIA-232E
and ITU-T V.28 specifications and operates at data rates up to
460 kbps.
All RS-232 (TxOUT and RxIN) inputs and outputs are protected
against electrostatic discharges (up to ±15 kV ESD protection).
This ensures compliance with IEC 1000-4-2 requirements.
This device is ideally suited for operation in electrically harsh
environments or where RS-232 cables are frequently plugged/
unplugged, with the ±15 kV ESD protection of the ADM3232E
RS-232 input/output pins.
Emissions are also controlled to within very strict limits. CMOS
technology is used to keep the power dissipation to an absolute
minimum, allowing maximum battery life in portable applications.
Four external 0.1 µF charge pump capacitors are used for the
voltage doubler/inverter, permitting operation from a single
3.3 V supply.
The ADM3232E is available in a 16-lead narrow and wide SOIC
packages, as well as a space-saving 16-lead TSSOP.
ADM3232E
Rev. B | Page 2 of 12
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
ESD Caution.................................................................................. 4
Pin Configuration and Function Descriptions..............................5
Typical Performance Characteristics ..............................................6
Theory of Operation .........................................................................8
Circuit Description .......................................................................8
High Baud Rate..............................................................................8
Outline Dimensions ..........................................................................9
Ordering Guide .......................................................................... 10
REVISION HISTORY
4/11—Rev. A to Rev. B
Changes to Features Section and General Description
Section ................................................................................................ 1
Change to ESD Protection (RS-232 I/O Pins) Parameter,
Table 1 ................................................................................................ 3
Change to ESD Protection on RS-232 Pins Section Heading..... 8
7/08—Rev. 0 to Rev. A
Added 16-Lead SOIC.........................................................Universal
Updated Outline Dimensions......................................................... 9
Changes to Ordering Guide .......................................................... 10
12/06—Revision 0: Initial Version
ADM3232E
Rev. B | Page 3 of 12
SPECIFICATIONS
VCC = 3.3 V ± 0.3 V, C1 to C4 = 0.1 µF; all specifications TMIN to TMAX, unless otherwise noted.
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
DC CHARACTERISTICS
Operating Voltage Range 3.0 3.3 5.5 V
VCC Power Supply Current 1.3 3 mA No load
LOGIC
Input Logic Threshold Low, VINL 0.8 V TIN
Input Logic Threshold High, VINH 2.0 V TIN
TTL/CMOS Output Voltage Low, VOL 0.4 V IOUT = 1.6 mA
TTLCMOS Output Voltage High, VOH VCC − 0.6 V IOUT = −1 mA
Logic Pull-Up Current 5 10 μA TIN = GND to VCC
Transmitter Input Hysteresis 0.5 V
RS-232 RECEIVER
Input Voltage Range −30 +30 V
Input Threshold Low 0.6 1.2 V
Input Threshold High 1.6 2.4 V
Input Hysteresis 0.4 V
Input Resistance 3 5 7 kΩ
RS-232 TRANSMITTER
Output Voltage Swing (RS-232) ±5.0 ±5.2 V VCC = 3.3 V, all transmitter outputs loaded with 3 kΩ to ground
Output Voltage Swing (RS-562) ±3.7 V VCC = 3.0 V
Transmitter Output Resistance 300 Ω VCC = 0 V, VOUT = ±2 V
Output Short-Circuit Current (RS-232) ±15 mA
TIMING CHARACTERISTICS
Maximum Data Rate 460 kbps VCC = 3.3 V, RL = 3 kΩ to 7 kΩ, CL = 50 pF to 1000 pF, one
Tx switching
Receiver Propagation Delay
tPHL 0.4 1 μs
tPLH 0.4 1 μs
Transmitter Propagation Delay 300 1.2 μs RL = 3 kΩ, CL = 1000 pF
Receiver Output Enable Time 200 ns
Receiver Output Disable Time 200 ns
Transmitter Skew 30 ns
Receiver Skew 300 ns
Transition Region Slew Rate 5.5 10 30 V/μs Measured from +3 V to −3 V or −3 V to +3 V, VCC = 3.3 V;
RL = 3 kΩ, CL = 1000 pF, TA = 25°C
ESD PROTECTION (RS-232 I/O PINS)
±15 kV Human body model
±15 kV IEC 1000-4-2 air discharge
±8 kV IEC 1000-4-2 contact discharge
ADM3232E
Rev. B | Page 4 of 12
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 2.
Parameter Rating
VCC −0.3 V to +6 V
V+ (VCC − 0.3 V) to 14 V
V− +0.3 V to –14 V
Input Voltages
TxIN −0.3 V to (VCC + 0.3 V)
RxIN ±30 V
Output Voltages
TxOUT ±15 V
RxOUT −0.3 V to (VCC + 0.3 V)
Short-Circuit Duration
TxOUT Continuous
Power Dissipation R-16/RW-16 450 mW
(Derate 6 mW/°C Above 50°C)
θJA, Thermal Impedance 158°C/W
Power Dissipation RU-16 500 mW
(Derate 6 mW/°C Above 50°C)
θJA, Thermal Impedance 158°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)
JEDEC industry-standard
J-STD-020
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
ADM3232E
Rev. B | Page 5 of 12
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
C1+
1
V+
2
C1–
3
C2+
4
V
CC
16
GND
15
T1
OUT
14
R1
IN
13
C2–
5
R1
OUT
12
V–
6
T1
IN
11
T2
OUT 7
T2
IN
10
R2
IN 8
R2
OUT
9
ADM3232E
TOP VIEW
(Not to Scale)
06410-002
Figure 2. Pin Configuration
Table 3. Pin Function Descriptions
Pin No. Mnemonic Description
1, 3 C1+, C1– External Capacitor 1 is connected between these pins. A 0.1 μF capacitor is recommended, but larger capacitors
of up to 47 μF can be used.
2 V+ Internally Generated Positive Supply (6 V Nominal).
4, 5 C2+, C2– External Capacitor 2 is connected between these pins. A 0.1 μF capacitor is recommended, but larger capacitors
of up to 47 μF can be used.
6 V– Internally Generated Negative Supply (−6 V Nominal).
7, 14 T2OUT, T1OUT Transmitter (Driver) Outputs. These are RS-232 signal levels (typically ±6 V).
8, 13 R2IN, R1IN Receiver Inputs. These inputs accept RS-232 signal levels. An internal 5 kΩ pull-down resistor to GND is connected
on each input.
9, 12 R2OUT, R1OUT Receiver Outputs. These are TTL/CMOS output logic levels.
10, 11 T2IN, T1IN Transmitter (Driver) Inputs. These inputs accept TTL/CMOS levels.
15 GND Ground Pin. Must be connected to 0 V.
16 VCC Power Supply Input (3.3 V ± 0.3 V).
ADM3232E
Rev. B | Page 6 of 12
TYPICAL PERFORMANCE CHARACTERISTICS
LOAD CAPACITANCE (pF)
8
6
4
2
0
–2
–4
–6
–8
0 1200200 400 600 800
Tx
OUT
(V)
1000
Tx
OUT
(HIGH)
Tx
OUT
(LOW)
0
6410-003
Figure 3. Transmitter Output Voltage High/Low vs.
Load Capacitance @ 460 kbps
V
CC
(V)
8
2.7 2.9 3.1 3.3 3.5
Tx
OUT
(V)
6
4
2
0
–2
–4
–6
–8
06410-004
Tx
OUT
LOW
Tx
OUT
HIGH
Figure 4. Transmitter Output Voltage vs. VCC
LOAD CURRENT (mA)
8
02468
Tx
OUT
(V)
6
4
2
0
–2
–4
–6
–8
10 12
Tx
OUT
HIGH
Tx
OUT
LOW
06410-005
Figure 5. Transmitter Output Voltage High/Low vs. Load Current
LOAD CURRENT (mA)
8
02468
V+
V+, V– (V)
6
4
2
0
–2
–4
–6
–8
V–
10 12
06410-006
Figure 6. Charge Pump V+, V− vs. Load Current
V
CC
(V)
350
2.7 2.9 3.1 3.3 3.5
IMPEDANCE (Ω)
300
250
200
150
100
50
0
V+ (IMPEDANCE)
V– (IMPEDANCE)
06410-007
Figure 7. Charge Pump Impedance vs. VCC
LOAD CAPACITANCE (pF)
20
0 1000 2000 3000
I
CC
@ 230kbps
I
CC
(mA)
18
16
14
12
10
2
0
8
6
4
I
CC
@ 460kbps
06410-008
Figure 8. Power Supply Current vs. Load Capacitance
ADM3232E
Rev. B | Page 7 of 12
1
CH 1 5.00V CH 2 5.00V M1.00µs CH1
2
T
06410-009
T
0V
Figure 9. 460 kbps Data Transmission
ADM3232E
Rev. B | Page 8 of 12
THEORY OF OPERATION
The ADM3232E is a single-channel RS-232 line driver/receiver.
Step-up voltage converters, coupled with level-shifting transmitters
and receivers, allow RS-232 levels to be developed while operating
from a single 3.3 V supply.
CMOS technology is used to keep the power dissipation to an
absolute minimum, allowing maximum battery life in portable
applications.
CIRCUIT DESCRIPTION
The internal circuitry consists of the following main sections:
• A charge pump voltage converter
• A 3.3 V logic to RS-232 transmitter
• An RS-232 to 3.3 V logic receiver
Charge Pump Voltage Converter
The charge pump voltage converter consists of a 200 kHz
oscillator and a switching matrix. The converter generates a
±6.6 V supply from the input 3.3 V level. This is accomplished
in two stages by using a switched capacitor technique as shown
in Figure 10. First, the 3.3 V input supply is doubled to 6.6 V by
using Capacitor C1 as the charge storage element. The +6.6 V
level is then inverted to generate −6.6 V, using C2 as the storage
element.
Capacitor C3 and Capacitor C4 are used to reduce the output
ripple. Their values are not critical and can be increased, if desired.
Capacitor C3 is shown connected between V+ and VCC. It is also
acceptable to connect this capacitor between V+ and GND.
If desired, larger capacitors (up to 10 µF) can be used for
Capacitor C1 to Capacitor C4.
C1+
C2+
C1–
C2–
V
CC
V–
V+
T1
IN
T1
OUT
T2
IN
T2
OUT
R1
OUT
R1
IN
R2
OUT
R2
IN
TTL/CMOS
INPUTS RS-232
OUTPUTS
TTL/CMOS
OUTPUTS
RS-232
INPUTS*
T1
T2
R1
R2
+
+
+
C1
0.1µF
10V
C2
0.1µF
10V
GND
ADM3232E
C3
0.1µF
6.3V
+3.3V INPUT
+3.3V TO +6.6V
VOLTAGE
DOUBLER
+6.6V TO –6.6V
VOLTAGE
INVERTER
C5
0.1µF
+
C4
0.1µF
10V
+
*INTERNAL 5kΩ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT.
5kΩ
5kΩ
06410-010
Figure 10. Typical Operating Circuit
C1 +C3 +
S3
S4
S1
S2
INTERNAL
OSCILLATOR
V
CC
GND V
CC
V+ = 2V
CC
06410-011
Figure 11. Charge Pump Voltage Doubler
C2 +C4 +
S3
S4
S1
S2
INTERNAL
OSCILLATOR
V+
GND V– = –(V+)
GND
FROM
VOLTAGE
DOUBLER
06410-012
Figure 12. Charge Pump Voltage Inverter
3.3 V Logic to RS-232 Transmitter
The drivers convert 3.3 V logic input levels into RS-232 output
levels. With VCC = 3.3 V and driving an RS-232 load, the output
voltage swing is typically ±6 V.
RS-232 to 3.3 V Logic Receiver
The receivers are inverting level shifters that accept RS-232 input
levels and translate them into 3 V logic output levels. The inputs
have internal 5 kΩ pull-down resistors to ground and are pro-
tected against overvoltages up to ±30 V. Unconnected inputs
are pulled to 0 V by the internal 5 k pull-down resistor. This
results in a Logic 1 output level for unconnected inputs or for
inputs connected to GND.
The receivers have Schmitt trigger inputs with a hysteresis level
of 0.4 V. This ensures error-free reception for both noisy inputs
and for inputs with slow transition times.
ESD Protection on RS-232 Pins
All RS-232 (TxOUT and RxIN) inputs and outputs are protected
against electrostatic discharges (up to ±15 kV). This ensures
compliance with IEC 1000-4-2 requirements.
HIGH BAUD RATE
The ADM3232E features high slew rates, permitting data trans-
mission at rates well in excess of the EIA-232E specifications.
RS-232 voltage levels are maintained at data rates up to 460 kbps,
even under worst-case loading conditions. The slew rate is
internally controlled to less than 30 V/µs to minimize EMI
interference.
ADM3232E
Rev. B | Page 9 of 12
OUTLINE DIMENSIONS
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
COMPLIANT TO JEDEC STANDARDS MS-012-AC
10.00 (0.3937)
9.80 (0.3858)
16 9
8
1
6.20 (0.2441)
5.80 (0.2283)
4.00 (0.1575)
3.80 (0.1496)
1.27 (0.0500)
BSC
SEATING
PLANE
0.25 (0.0098)
0.10 (0.0039)
0.51 (0.0201)
0.31 (0.0122)
1.75 (0.0689)
1.35 (0.0531)
0.50 (0.0197)
0.25 (0.0098)
1.27 (0.0500)
0.40 (0.0157)
0.25 (0.0098)
0.17 (0.0067)
COPLANARITY
0.10
8°
0°
060606-A
45°
Figure 13. 16-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-16)
Dimensions shown in millimeters (and inches)
16 9
81
PIN 1
SEATING
PLANE
8°
0°
4.50
4.40
4.30
6.40
BSC
5.10
5.00
4.90
0.65
BSC
0.15
0.05
1.20
MAX
0.20
0.09 0.75
0.60
0.45
0.30
0.19
COPLANARITY
0.10
COMPLIANT TO JEDEC STANDARDS MO-153-AB
Figure 14. 16-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-16)
Dimensions shown in millimeters
ADM3232E
Rev. B | Page 10 of 12
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
COMPLIANT TO JEDEC STANDARDS MS-013-AA
10.50 (0.4134)
10.10 (0.3976)
0.30 (0.0118)
0.10 (0.0039)
2.65 (0.1043)
2.35 (0.0925)
10.65 (0.4193)
10.00 (0.3937)
7.60 (0.2992)
7.40 (0.2913)
0.75(0.0295)
0.25(0.0098)
45°
1.27 (0.0500)
0.40 (0.0157)
C
OPLANARITY
0.10 0.33 (0.0130)
0.20 (0.0079)
0.51 (0.0201)
0.31 (0.0122)
SEATING
PLANE
8°
0°
16 9
8
1
1.27 (0.0500)
BSC
03-27-2007-B
Figure 15. 16-Lead Standard Small Outline Package [SOIC_W]
Wide Body
(RW-16)
Dimensions shown in millimeters (and inches)
ORDERING GUIDE
Model1 Temperature Range Package Description Package Option
ADM3232EARNZ –40°C to +85°C 16-Lead SOIC_N R-16
ADM3232EARNZ-REEL7 –40°C to +85°C 16-Lead SOIC_N R-16
ADM3232EARUZ –40°C to +85°C 16-Lead TSSOP RU-16
ADM3232EARUZ-REEL7 –40°C to +85°C 16-Lead TSSOP RU-16
ADM3232EARWZ –40°C to +85°C 16-Lead SOIC_W RW-16
ADM3232EARWZ-REEL –40°C to +85°C 16-Lead SOIC_W RW-16
1 Z = RoHS Compliant Part.
ADM3232E
Rev. B | Page 11 of 12
NOTES
ADM3232E
Rev. B | Page 12 of 12
NOTES
©2006–2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06410-0-4/11(B)
