Preliminary Technical Data
FEATURES
460 kbps Data Rate
1 Tx and 1 Rx
Meets EIA-232E specifications
0.1uF charge pump capacitors
Integrated isolated dc-to-dc converter
ESD protection to IEC1000-4-2(801.2)
on R
IN
and T
OUT
pins.
±8kV: contact discharge
±15kV: air gap discharge
Integrated isolated dc-to-dc converter
High common-mode transient immunity: >25kV/us
Safety and regulatory approvals (pending)
UL recognition
VDE certificate of conformity
20 Lead WSOIC package
Isolated Single Channel RS-232
Line Driver/Receiver
ADM3251E
FUNCTIONAL BLOCK DIAGRAM
APPLICATIONS
High noise data communications
Industrial Communications
Industrial/Telecom Diagnostic Ports
Figure 1.
GENERAL DESCRIPTION
The ADM3251E is a high speed, single-channel RS-232
transceiver device that operates from a single power supply.
This device is ideally suited to operation in electrically harsh
environments or where RS-232 cables are frequently being
plugged/unplugged.
The ADM3251E incorporates dual-channel digital isolators with
isoPower
integrated, isolated power. There is no requirement
for a separate isolated dc-to-dc converter as the ADM3251E has
a chip-scale dc-to-dc converter which is based on Analog
Devices, Inc.
iCoupler®
technology.
Analog Devices’ chip-scale transformer
iCoupler
technology is
used both for the isolation of the logic signals as well as for the
dc-to-dc converter. The result is a small form factor, total
isolation solution.
Five external 0.1μF charge pump capacitors are used for the
voltage doubler/inverter permitting operation from a single
supply.
The ADM3251E conforms to the EIA-232E specifications and
operates at data rates up to 460 kbps.
The device is ideally suited to operation in electrically harsh
environments. RS-232 pins, R
IN
and T
OUT
are protected against
electrostatic discharges (up to ±15 kV ESD protection).
The ADM3251E is available in a 20 lead Wide Body SOIC
package.
Rev. PrA
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2008 Analog Devices, Inc. All rights reserved.
ADM3251E
TARGET SPECIFICATIONS
Preliminary Technical Data
All voltages are relative to their respective ground. All min/max specifications apply over the entire recommended operating range, unless
otherwise noted. All typical specifications in Table 1 are at T
A
= 25°C, V
CC
= 5.0V, unless otherwise noted.
Table 1.
Parameter
DC CHARACTERISTICS
V
CC
Operating Voltage Range
DC-to-DC Converter Enable Threshold, V
CC(Enable) 1
DC-to-DC Converter Disable Threshold, V
CC(Disable) 1
DC-to-DC CONVERTER ENABLED
Input Supply Current
V
ISO
Output
2
DC-to-DC CONVERTER DISABLED
Primary Side Supply Input Current, I
CC(Disable)
LOGIC
Transmitter Input, T
IN
Logic Input Current, I
TIN
Logic Low Input Threshold, V
TINL
Logic High Input Threshold, V
TINH
Receiver Output, R
OUT
Logic High Output V
ROUTH
Logic Low Output V
ROUTL
RS-232
RECEIVER
EIA-232 Input Voltage Range
3
EIA-232 Input Threshold Low
EIA-232 Input Threshold High
EIA-232 Input Hysteresis
EIA-232 Input Resistance
TRANSMITTER
Output Voltage Swing (RS-232)
Transmitter Output Resistance
RS-232 Output Short Circuit Current
TIMING CHARACTERISTICS
Maximum Data Rate
Receiver Propagation Delay
t
PHL
t
PLH
Transmitter Propagation Delay
Transmitter Skew
Receiver Skew
Transition Region Slew Rate
3
AC SPECIFICATIONS
Output Rise, t
R
/Fall time, t
F
(10% to 90%)
Common-Mode Transient Immunity at Logic High Output
Common-Mode Transient Immunity at Logic Low Output
ESD PROTECTION (R
IN
and T
OUT
Pins)
Min
4.5
4.5
Typ
Max
5.5
3.7
TBD
TBD
Unit
V
V
V
mA
mA
V
mA
Test Conditions/Comments
5.0
TBD
No Load
R
L
= 3kΩ
I
ISO
=0uA
V
ISO
= 3.3V, Vcc ≤3.7V
-10
0.3 V
CC
+0.01
+10
0.7 V
CC
µA
V
V
V
V
V
V
I
ROUTH
= - 20 µA
I
ROUTH
= - 4 mA
I
ROUTH
= 20 µA
I
ROUTH
= 4 mA
V
CC
− 0.1
V
CC
− 0.5
V
CC
V
CC
− 0.2
0.0
0.0
0.1
0.4
−30
0.6
+30
1.3
1.6
0.4
5
±5.7
TBD
2.4
7
3
±5
300
V
V
V
V
kΩ
V
Ω
mA
kbps
R
L
= 3kΩ to Gnd
V
ISO
= 0V
460
190
135
650
80
70
10
R
L
= 3kΩ to7kΩ, C
L
=50 pF to 1000 pF
5.5
30
µs
µs
µs
ns
ns
V/µs
R
L
= 3kΩ, C
L
=1000 pF
+3V to -3V or -3V t0 3V, V
cc
=+3.3V,
R
L
=+3kΩ,
C
L
=1000pF, T
A
=25C.
C
L
= 15 pF, CMOS signal levels
2.3
TBD
TBD
±15
±8
ns
KV/ µs
KV/ µs
kV
kV
Human Body Model Air Discharge
Human Body Model Contact Discharge
1 Enable/disable threshold is the VCC voltage at which the internal DC-to-DC converter is enabled/disabled.
2 To maintain datasheet specifications no current should be drawn from V
ISO.
3 Guaranteed by design
Rev. PrA | Page 2 of 6
Preliminary Technical Data
TARGET SPECIFICATIONS
ADM3251E
All voltages are relative to their respective ground. All min/max specifications apply over the entire recommended operating range, unless
otherwise noted. All typical specifications in Table 2 are at T
A
= 25°C, V
CC
= 3.3V (
DC-to-DC
converter disabled), the secondary side is powered
externally by V
ISO
=3.3V, unless otherwise noted.
Table 2.
Parameter
DC CHARACTERISTICS
V
CC
Operating Voltage Range
DC-to-DC Converter Disable Threshold, V
CC(Disable) 1
DC-to-DC CONVERTER DISABLED
V
ISO
Primary Side Supply Input Current, I
CC(Disable)
Secondary Side Supply Input Current, I
ISO(Disable)
LOGIC
Transmitter Input, T
IN
Logic Input Current, I
TIN
Logic Low Input Threshold, V
TINL
Logic High Input Threshold, V
TINH
Receiver Output, R
OUT
Logic High Output V
ROUTH
Logic Low Output V
ROUTL
RS-232
RECEIVER
EIA-232 Input Voltage Range
2
EIA-232 Input Threshold Low
EIA-232 Input Threshold High
EIA-232 Input Hysteresis
EIA-232 Input Resistance
TRANSMITTER
Output Voltage Swing (RS-232)
Transmitter Output Resistance
RS-232 Output Short Circuit Current
TIMING CHARACTERISTICS
Maximum Data Rate
Receiver Propagation Delay
t
PHL
t
PLH
Transmitter Propagation Delay
Transmitter Skew
Receiver Skew
Transition Region Slew Rate
2
AC SPECIFICATIONS
Output Rise, t
R
/Fall time, t
F
(10% to 90%)
Common-Mode Transient Immunity at Logic High Output
Common-Mode Transient Immunity at Logic Low Output
ESD PROTECTION (R
IN
and T
OUT
Pins)
Min
3.0
Typ
Max
3.7
3.7
5.5
TBD
TBD
Unit
V
V
V
mA
mA
Test Conditions/Comments
3.0
No Load
R
L
=3kΩ
-10
0.3 V
CC
+0.01
+10
0.7 V
CC
µA
V
V
V
V
V
V
I
ROUTH
= - 20 µA
I
ROUTH
= - 4 mA
I
ROUTH
= 20 µA
I
ROUTH
= 4 mA
V
CC
− 0.1
V
CC
− 0.5
V
CC
V
CC
− 0.2
0.0
0.0
0.1
0.4
−30
0.6
+30
1.3
1.6
0.4
5
±5.7
TBD
2.4
7
3
±5
300
V
V
V
V
kΩ
V
Ω
mA
kbps
V
ISO
= 3.3V, R
L
= 3kΩ to Gnd
V
ISO
= 0V
460
V
ISO
= 3.3V, R
L
= 3kΩ to7kΩ, C
L
=50 pF to
1000pF
5.5
190
135
650
80
55
10
30
µs
µs
µs
ns
ns
V/µs
R
L
= 3kΩ, C
L
=1000 pF
+3V to -3V, or -3V to +3V, V
cc
= 3.3V,
R
L
=3kΩ, C
L
=1000pF, T
A
=25C.
C
L
= 15 pF, CMOS signal levels
2.3
TBD
TBD
±15
±8
ns
KV/ µs
KV/ µs
kV
kV
Human Body Model Air Discharge
Human Body Model Contact Discharge
1 Enable/disable threshold is the VCC voltage at which the internal DC-to-DC converter is enabled/disabled.
2 Guaranteed by design
:
Rev. PrA | Page 3 of 6
ADM3251E
ABSOLUTE MAXIMUM RATINGS
Table 6.
Parameter
V
CC
V+
V−
Input Voltages
T
IN
R
IN
Output Voltages
T
OUT
R
OUT
Short Circuit Duration
T
OUT
Power Dissipation
Power dissipation CP-12
θ
JA
, Thermal Impedance
Operating Temperature Range
Industrial
Storage Temperature Range
Pb-Free Temperature (Soldering, 30 sec)
Rating
−0.3 V to +6 V
(V
CC
− 0.3 V) to +13 V
+0.3 V to –13 V
−0.3 V to (V+, +0.3 V)
±30 V
±15 V
−0.3 V to (V
CC
+ 0.3 V)
Continuous
TBD
TBD
−40°C to +85°C
−65°C to +150°C
260°C
Preliminary Technical Data
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only and 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
Rev. PrA | Page 4 of 6
Preliminary Technical Data
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
ADM3251E
Figure 2. ADM3251E Pin Configuration
Table 7. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Mneumonic
NC
V
cc
V
cc
GND
GND
GND
GND
R
OUT
T
IN
GND
GND
ISO
V-
C2-
C2+
R
IN
T
OUT
C1-
C1+
V+
V
ISO
Description
Not Connected
Power Supply Input
Power Supply Input
Ground Pin
Ground Pin
Ground Pin
Ground Pin
Receiver Output. This outputs CMOS output logic levels.
Transmitter (Driver) Input. This input accepts TTL/CMOS levels.
Ground Pin
Ground reference for Isolator Primary Side.
Internally Generated Negative Supply
External Capacitor 2 is connected between pins 13 and 14. A 0.1μF capacitor is recommended but larger
capacitors up to 47uF may be used.
External Capacitor 2 is connected between pins 13 and 14. A 0.1μF capacitor is recommended but larger
capacitors up to 47uF may be used.
Receiver Input. This input accepts RS-232 signal levels.
Transmitter (Driver) Output. This outputs RS-232 signal levels.
External Capacitor 1 is connected between pins 17 and 18. A 0.1μF capacitor is recommended but larger
capacitors up to 47uF may be used.
External Capacitor 1 is connected between pins 17 and 18. A 0.1μF capacitor is recommended but larger
capacitors up to 47uF may be used.
Internally Generated Positive Supply
Isolated Supply Voltage for Isolator Secondary Side.
Rev. PrA | Page 5 of 6
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