Isolated, Single-Channel
RS-232 Line Driver/Receiver
Data Sheet
FEATURES
2.5 kV fully isolated (power and data) RS-232 transceiver
iso
Power integrated, isolated dc-to-dc converter
460 kbps data rate
1 Tx and 1 Rx
Meets EIA/TIA-232E specifications
ESD protection on RIN and TOUT pins
±8 kV: contact discharge
±15 kV: air gap discharge
0.1 μF charge pump capacitors
High common-mode transient immunity: >25 kV/μs
UL recognition
2500 V rms for 1 minute per UL 1577
VDE Certificate of Conformity
DIN EN 60747-5-2 (VDE 0884 Teil 2): 2003-01
CSA Component Acceptance Notice #5A
Operating temperature range: 40°C to +85°C
Wide body, 20-lead SOIC package
APPLICATIONS
High noise data communications
Industrial communications
General-purpose RS232 data links
Industrial/telecommunications diagnostic ports
Medical equipment
FUNCTIONAL BLOCK DIAGRAM
07388-
001
DECODE
RECT
REG
V–
C4
0.1F
16V
VOLTAGE
DOUBLER
C1+ C1– V+
VISO
C2+ C2–
R
T
VOLTAGE
INVERTER
VCC
ROUT
TIN
GND
GNDISO
RIN*
TOUT
ADM3251E
OSC
ENCODE
DECODE
*INTERNAL
5k PULL-DOWN RESISTOR ON THE RS-232 INPUT.
0.1F
C3
0.1F
10V
C2
0.1F
16V
0.1F
C1
0.1F
16V
Figure 1.
GENERAL DESCRIPTION
T
he ADM3251E1 is a high speed, 2.5 kV fully isolated, single-
channel RS-232/V.28 transceiver device that operates from a
single 5 V power supply. Due to the high ESD protection on the
RIN and TOUT pins, the device is ideally suited for operation in
electrically harsh environments or where RS-232 cables are
frequently being plugged and unplugged.
T
he ADM3251E incorporates dual-channel digital isolators
with isoPower integrated, isolated power. There is no requirement
to use a separate isolated dc-to-dc converter. Chip-scale trans-
former iCoupler technology from Analog Devices, Inc., is used
both for the isolation of the logic signals as well as for the inte-
grated dc-to-dc converter. The result is a total isolation solution.
T
he ADM3251E contains isoPower technology that uses high
frequency switching elements to transfer power through the
transformer. Special care must be taken during printed circuit
board (PCB) layout to meet emissions standards. Refer to
isoPower Devices, for details on board layout considerations.
specifications and operates at data rates up to 460 kbps.
Four external 0.1 μF charge pump capacitors are used for the
voltage doubler/inverter, permitting operation from a single
5 V supply.
The
ADM3251E is available in a 20-lead, wide body SOIC package
and is specified over the 40°C to +85°C temperature range.
1
Protected by U.S. Patents 5,952,849; 6,873,065; and 7,075,329.
Rev. G
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