ANALOG DEVICES ADM3251E Service Manual
www.BDTIC.com/ADI
Isolated Single Channel RS-232
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
and T
IN
±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
APPLICATIONS
High noise data communications
Industrial Communications
Industrial/Telecom Diagnostic Ports
OUT
pins.
)
Line Driver/Receiver
ADM3251E
FUNCTIONAL BLOCK DIAGRAM
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.
Rev. Pr B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
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.
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
electrostatic discharges (up to ±15 kV ESD protection).
The ADM3251E is available in a 20 lead Wide Body SOIC
package.
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.
and T
IN
are protected against
OUT
ADM3251E Preliminary Technical Data
www.BDTIC.com/ADI
TARGET SPECIFICATIONS
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
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
DC CHARACTERISTICS
V
Operating Voltage Range 4.5 5.5 V
CC
DC-to-DC Converter Enable Threshold, V
DC-to-DC Converter Disable Threshold, V
DC-to-DC CONVERTER ENABLED
Input Supply Current TBD mA No Load
TBD mA R
V
Output2
ISO
DC-to-DC CONVERTER DISABLED
Primary Side Supply Input Current, I
LOGIC
Transmitter Input, TIN
Logic Input Current, I
Logic Low Input Threshold, V
Logic High Input Threshold, V
Receiver Output, R
Logic High Output V
-10 +0.01 +10 µA
TIN
0.3 VCC V
TINL
TINH
OUT
V
ROUTH
VCC − 0.5 VCC − 0.2 V I
Logic Low Output V
0.0 0.1 V I
ROUTL
0.0 0.4 V I
RS-232
RECEIVER
EIA-232 Input Voltage Range 3 −30 +30 V
EIA-232 Input Threshold Low 0.6 1.3 V
EIA-232 Input Threshold High 1.6 2.4 V
EIA-232 Input Hysteresis 0.4 V
EIA-232 Input Resistance 3 5 7 kΩ
TRANSMITTER
Output Voltage Swing (RS-232) ±5 ±5.7 V RL = 3kΩ to Gnd
Transmitter Output Resistance 300 Ω V
RS-232 Output Short Circuit Current TBD mA
TIMING CHARACTERISTICS
Maximum Data Rate 460 kbps RL = 3kΩ to7kΩ, CL=50 pF to 1000 pF
Receiver Propagation Delay
t
190 µs
PHL
t
135 µs
PLH
Transmitter Propagation Delay 650 µs RL = 3kΩ, CL=1000 pF
Transmitter Skew 80 ns
Receiver Skew 70 ns
Transition Region Slew Rate3 5.5 10 30 V/µs
AC SPECIFICATIONS
Output Rise, tR/Fall time, tF (10% to 90%) 2.3 ns CL = 15 pF, CMOS signal levels
Common-Mode Transient Immunity at Logic High Output TBD KV/ µs
Common-Mode Transient Immunity at Logic Low Output TBD KV/ µs
ESD PROTECTION (R
and T
IN
Pins) ±15 kV Human Body Model Air Discharge
OUT
±8 kV 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
3 Guaranteed by design
1
4.5 V
CC(Enable)
1
3.7 V
CC(Disable)
TBD mA V
CC(Disable)
0.7 VCC V
= 25°C, VCC = 5.0V, unless otherwise noted.
A
5.0 V I
− 0.1 VCC V I
CC
ISO.
= 3kΩ
L
=0uA
ISO
= 3.3V, Vcc ≤3.7V
ISO
= - 20 µA
ROUTH
= - 4 mA
ROUTH
= 20 µA
ROUTH
= 4 mA
ROUTH
= 0V
ISO
+3V to -3V or -3V t0 3V, V
=+3kΩ, CL=1000pF, TA=25C.
R
L
cc
=+3.3V,
Rev. Pr B | Page 2 of 6
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