Datasheet

LTC1535
1
1535fc
For more information www.linear.com/LTC1535
Typical applicaTion
FeaTures DescripTion
Isolated RS485 Transceiver
The LT C
®
1535 is an isolated RS485 full-duplex differential
line transceiver. Isolated RS485 is ideal for systems where
the ground loop is broken to allow for much larger com-
mon mode voltage ranges. An internal capacitive isola-
tion barrier provides 2500V
RMS
of isolation between the
line transceiver and the logic level interface. The powered
side contains a 420kHz push-pull converter to power the
isolated RS485 transceiver. Internal full-duplex commu-
nication occurs through the capacitive isolation barrier.
The transceiver meets RS485 and RS422 requirements.
The driver and receiver feature three-state outputs, with
the driver maintaining high impedance over the entire
common mode range. The drivers have short-circuit cur-
rent limits in both directions and a slow slew rate select
to minimize EMI or reflections. The 68kΩ
receiver input
allows up to 128 node connections. A fail-safe feature
defaults to a high output state when the receiver inputs
are open or shorted.
applicaTions
n
UL Rated Isolated RS485: 2500V
RMS
UL Recognized
®
File #E151738
n
Eliminates Ground Loops
n
250kBd Maximum Data Rate
n
Self-Powered with 420kHz Converter
n
Half- or Full-Duplex
n
Fail-Safe Output High for Open or
Shorted Receiver Inputs
n
Short-Circuit Current Limit
n
Slow Slew Rate Control
n
68kΩ Input Impedance Allows Up to 128 Nodes
n
Thermal Shutdown
n
8kV ESD Protection On Driver Outputs and
Receiver Inputs
n
Available in 28-Lead SW Package
n
Isolated RS485 Receiver/Driver
n
RS485 with Large Common Mode Voltage
n
Breaking RS485 Ground Loops
n
Multiple Unterminated Line Taps
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Analog
Devices, Inc. All other trademarks are the property of their respective owners.
**
D
Y
Z
SLO
2
1
1
R
A
B
RO2
1535 TA01
V
CC
RO
RE
DE
DI
GND
LOGIC COMMON
2
FLOATING RS485 COMMON
** EATON (888) 414-2645
420kHz
28
27
26
25
4
17
15
16
18
12
13
1411
1
+
+
GND2
1/2 BAT54C
1/2 BAT54C
V
CC2
ST1 ST2
32
V
CC
RO
RE
DE
DI
1
10µF
10µF
2
CTX02-14659
TWISTED-PAIR
CABLE
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