1
LTC491
491fa
Low Power: I
CC
= 300µA Typical
Designed for RS485 or RS422 Applications
Single 5V Supply
–7V to 12V Bus Common Mode Range
Permits ±7V Ground Difference Between Devices
on the Bus
Thermal Shutdown Protection
Power-Up/-Down Glitch-Free Driver Outputs Permit
Live Insertion or Removal of Package
Driver Maintains High Impedance in Three-State or
with the Power Off
Combined Impedance of a Driver Output and
Receiver Allows up to 32 Transceivers on the Bus
70mV Typical Input Hysteresis
28ns Typical Driver Propagation Delays with 5ns
Skew for 2.5MB Operation
Pin Compatible with the SN75180
Available in 14-Lead PDIP and SO Packages
Differential Driver and
Receiver Pair
The LTC
®
491 is a low power differential bus/line trans-
ceiver designed for multipoint data transmission standard
RS485 applications with extended common mode range
(12V to –7V). It also meets the requirements of RS422.
The CMOS design offers significant power savings over its
bipolar counterpart without sacrificing ruggedness against
overload or ESD damage.
The driver and receiver feature three-state outputs, with
the driver outputs maintaining high impedance over the
entire common mode range. Excessive power dissipation
caused by bus contention or faults is prevented by a
thermal shutdown circuit which forces the driver outputs
into a high impedance state.
The receiver has a fail safe feature which guarantees a high
output state when the inputs are left open.
Both AC and DC specifications are guaranteed from 0°C to
70°C and 4.75V to 5.25V supply voltage range.
Low Power RS485/RS422 Transceiver
Level Translator
LTC491 • TA01
120120
120120
4000 FT 24 GAUGE TWISTED PAIR
4000 FT 24 GAUGE TWISTED PAIR
RECEIVER
LTC491
DRIVER RECEIVER
LTC491
DRIVER
R
D
R
D5
2
11
12
10
9
4
DE
3
REB
DE
REB
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
, LTC and LT are registered trademarks of Linear Technology Corporation.
LTC491
2
491fa
A
U
G
W
A
W
U
W
ARBSOLUTEXI T
IS
WU
U
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
LTC491CN
LTC491CS
LTC491IN
LTC491IS
(Note 1)
Supply Voltage (V
CC
) ............................................... 12V
Control Input Voltages .................... 0.5V to V
CC
+ 0.5V
Control Input Currents .......................... –50mA to 50mA
Driver Input Voltages ...................... 0.5V to V
CC
+ 0.5V
Driver Input Currents ............................ –25mA to 25mA
Driver Output Voltages .......................................... ±14V
Receiver Input Voltages ......................................... ±14V
Receiver Output Voltages ............... 0.5V to V
CC
+ 0.5V
Operating Temperature Range
LTC491C ................................................. 0°C to 70°C
LTC491I.............................................. 40°C to 85°C
Storage Temperature Range ................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V ±5%
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OD1
Differential Driver Output Voltage (Unloaded) I
O
= 0 5V
V
OD2
Differential Driver Output Voltage (With load) R = 50; (RS422) 2V
R = 27; (RS485) (Figure 1) 1.5 5 V
V
OD
Change in Magnitude of Driver Differential Output R = 27 or R = 50 (Figure 1) 0.2 V
Voltage for Complementary Output States
V
OC
Driver Common Mode Output Voltage 3V
∆ V
OC
Change in Magnitude of Driver Common Mode 0.2 V
Output Voltage for Complementary Output States
V
IH
Input High Voltage D, DE, REB 2.0 V
V
IL
Input Low Voltage 0.8 V
l
IN1
Input Current ±2µA
l
IN2
Input Current (A, B) V
CC
= 0V or 5.25V V
IN
= 12V 1.0 mA
V
IN
= –7V 0.8 mA
V
TH
Differential Input Threshold Voltage for Receiver 7V V
CM
12V 0.2 0.2 V
V
TH
Receiver Input Hysteresis V
CM
= 0V 70 mV
V
OH
Receiver Output High Voltage I
O
= –4mA, V
ID
= 0.2V 3.5 V
V
OL
Receiver Output Low Voltage I
O
= 4mA, V
ID
= –0.2V 0.4 V
I
OZR
Three-State Output Current at Receiver V
CC
= Max 0.4V V
O
2.4V ±1µA
I
CC
Supply Current No Load; D = GND, Outputs Enabled 300 500 µA
or V
CC
Outputs Disabled 300 500 µA
R
IN
Receiver Input Resistance 7V V
CM
12V 12 k
I
OSD1
Driver Short Circuit Current, V
OUT
= High V
O
= –7V 100 250 mA
I
OSD2
Driver Short Circuit Current, V
OUT
= Low V
O
= 12V 100 250 mA
I
OSR
Receiver Short Circuit Current 0V V
O
V
CC
785mA
I
OZ
Driver Three-State Output Current V
O
= –7V to 12V ±2±200 µA
14
13
12
11
10
9
87
6
5
4
3
2
1
TOP VIEW
S PACKAGE
14-LEAD PLASTIC SO
NC
N PACKAGE
14-LEAD PDIP
Y
NC
Z
B
NC
V
CC
D
GND
GND
R
REB
DE
A
R
D
T
JMAX
= 100°C, θ
JA
= 90°C/W (N)
T
JMAX
= 100°C, θ
JA
= 110°C/W (S)
Consult LTC Marketing for parts specified with wider operating temperature ranges.
DC ELECTRICAL CHARACTERISTICS
3
LTC491
491fa
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
PLH
Driver Input to Output R
DIFF
= 54, C
L1
= C
L2
= 100pF 10 30 50 ns
t
PHL
Driver Input to Output 10 30 50 ns
t
SKEW
Driver Output to Output 5ns
t
r
, t
f
Driver Rise or Fall Time 51525 ns
t
ZH
Driver Enable to Output High C
L
= 100pF (Figures 4, 6) S2 Closed 40 70 ns
t
ZL
Driver Enable to Output Low C
L
= 100pF (Figures 4, 6) S1 Closed 40 70 ns
t
LZ
Driver Disable Time From Low C
L
= 15pF (Figures 4, 6) S1 Closed 40 70 ns
t
HZ
Driver Disable Time From High C
L
= 15pF (Figures 4, 6) S2 Closed 40 70 ns
t
PLH
Receiver Input to Output R
DIFF
= 54, C
L1
= C
L2
= 100pF 40 70 150 ns
t
PHL
Receiver Input to Output 40 70 150 ns
t
SKD
t
PLH
– t
PHL
Differential Receiver Skew 13 ns
t
ZL
Receiver Enable to Output Low C
L
= 15pF (Figures 3, 8) S1 Closed 20 50 ns
t
ZH
Receiver Enable to Output High C
L
= 15pF (Figures 3, 8) S2 Closed 20 50 ns
t
LZ
Receiver Disable From Low C
L
= 15pF (Figures 3, 8) S1 Closed 20 50 ns
t
HZ
Receiver Disable From High C
L
= 15pF (Figures 3, 8) S2 Closed 20 50 ns
S
U
GC CHARA TERISTICS
WITCHI
(Figures 2, 5)
(Figures 2, 7)
Note 3: All typicals are given for V
CC
= 5V and temperature = 25°C.Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to device ground unless
otherwise specified.
NC (Pin 1): Not Connected.
R (Pin 2): Receiver Output. If the receiver output is enabled
(REB low), then if A > B by 200mV, R will be high. If A < B
by 200mV, then R will be low.
REB (Pin 3): Receiver Output Enable. A low enables the
receiver output, R. A high input forces the receiver output
into a high impedance state.
DE (Pin 4): Driver Output Enable. A high on DE enables the
driver outputs, Y and Z. A low input forces the driver
outputs into a high impedance state.
D (Pin 5): Driver Input. If the driver outputs are enabled
(DE high), then a low on D forces the driver outputs Y low
and Z high. A high on D will force Y high and Z low.
GND (Pin 6): Ground Connection.
GND (Pin 7): Ground Connection.
NC (Pin 8): Not Connected.
Y (Pin 9): Driver Output.
Z (Pin 10): Driver Output.
B (Pin 11): Receiver Input.
A (Pin 12): Receiver Input.
NC (Pin 13): Not Connected.
V
CC
(Pin 14): Positive Supply; 4.75V V
CC
5.25V.
The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V ±5%
UU
U
PI FU CTIO S
LTC491
4
491fa
TTL Input Threshold vs Temperature Driver Skew vs Temperature Supply Current vs Temperature
Driver Output High Voltage Driver Differential Output Voltage Driver Output Low Voltage
vs Output Current, TA = 25°C vs Output Current, TA = 25°C vs Output Current, TA = 25°C
Driver Differential Output Voltage Receiver tPLH tPHLReceiver Output Low Voltage
vs Temperature, RO = 54vs Temperature vs Temperature at I = 8mA
TYPICAL PERFOR A CE CHARACTERISTICS
UW
OUTPUT VOLTAGE (V)
0
OUTPUT CURRENT (mA)
0
–24
4 8
–72
–96
1234
LTC491 • TPC01 OUTPUT VOLTAGE (V)
0
OUTPUT CURRENT (mA)
0
16
32
48
64
1234
LTC491 • TPC02
OUTPUT VOLTAGE (V)
0
OUTPUT CURRENT (mA)
0
20
40
60
80
1234
LTC491 • TPC03
TEMPERATURE (°C )
–50
INPUT THRESHOLD VOLTAGE (V)
1.55
1.57
1.59
1.61
1.63
0 50 100
LTC491 • TPC04
TEMPERATURE (°C )
–50
TIME (ns)
1.0
2.0
3.0
4.0
5.0
0 50 100
LTC491 • TPC05
TEMPERATURE (°C )
–50
SUPPLY CURRENT (µA)
310
320
330
340
350
0 50 100
LTC491 • TPC06
TEMPERATURE (°C )
–50
DIFFERENTIAL VOLTAGE (V)
1.5
1.7
1.9
2.1
2.3
0 50 100
LTC491 • TPC07
TEMPERATURE (°C )
–50
TIME (ns)
3.0
4.0
5.0
6.0
7.0
0 50 100
LTC491 • TPC08
TEMPERATURE (°C )
–50
OUTPUT VOLTAGE (V)
0
0.2
0.4
0.6
0.8
0 50 100
LTC491 • TPC09
5
LTC491
491fa
Figure 2. Driver/Receiver Timing Test Circuit
Figure 1. Driver DC Test Load
Figure 3. Receiver Timing Test Load
Figure 4. Driver Timing Test Load
TEST CIRCUITS
LTC491 • F01
Y
Z
R
R
VOD2
VOC
LTC491 • F02
DRIVER
D
Y
Z
RECEIVER
R
DIFF
A
B 15pF
C
L1
C
L2
R
LTC491 • F03
RECEIVER
OUTPUT
CL
S1
1k
CC
V
S2
1k
LTC491 • F04
OUTPUT
UNDER TEST
C
L
S1
500
CC
V
S2
LTC491
6
491fa
Figure 5. Driver Propagation Delays
Figure 6. Driver Enable and Disable Times
Figure 7. Receiver Propagation Delays
Figure 8. Receiver Enable and Disable Times
SWITCHI G TI E WAVEFOR S
UWW
–V
O
LTC491 • F05
D3V
0V
1.5V
t
PLH
1.5V
V
DIFF
= V(Y) – V(Z)
V
O
80%
20%
50%
10%
Z
Yt
SKEW
t
r
f = 1MHz : t
r
10ns : t
f
10ns
90%
50%
t
PHL
t
f
V
O
t
SKEW
1/2 V
O
1/2 V
O
LTC491 • F06
A, B
DE 3V
0V
f = 1MHz : t
r
10ns : t
r
10ns
V
OL
V
OH
1.5V 1.5V
5V
OUTPUT NORMALLY LOW
t
ZL
2.3V
t
LZ
0.5V
A, B
0V t
ZH
2.3V OUTPUT NORMALLY HIGH
t
HZ
0.5V
V
OL
LTC491 • F07
A-B
V
OD2
0V
t
PLH
0V
OUTPUT
V
OH
1.5V
f = 1MHz ; t
r
10ns : t
f
10ns
t
PHL
–V
OD2
1.5V
INPUT
R
LTC491 • F08
R
REB 3V
0V
f = 1MHz : t
r
10ns : t
f
10ns
V
OL
V
OH
1.5V 1.5V
5V
OUTPUT NORMALLY LOW
t
ZL
1.5V
t
LZ
0.5V
R
0V t
ZH
1.5V OUTPUT NORMALLY HIGH
t
HZ
0.5V
7
LTC491
491fa
Typical Application
A typical connection of the LTC491 is shown in Figure 9.
Two twisted-pair wires connect up to 32 driver/receiver
pairs for full duplex data transmission. There are no
restrictions on where the chips are connected to the wires,
and it isn’t necessary to have the chips connected at the
ends. However, the wires must be terminated only at the
ends with a resistor equal to their characteristic imped-
ance, typically 120. The input impedance of a receiver is
typically 20k to GND, or 0.6 unit RS-485 load, so in
practice 50 to 60 transceivers can be connected to the
same wires. The optional shields around the twisted pair
help reduce unwanted noise, and are connected to GND at
one end.
The LTC491 can also be used as a line repeater as shown
in Figure 10. If the cable length is longer than 4000 feet, the
LTC491 is inserted in the middle of the cable with the
receiver output connected back to the driver input.
Thermal Shutdown
The LTC491 has a thermal shutdown feature which pro-
tects the part from excessive power dissipation. If the
outputs of the driver are accidently shorted to a power
supply or low impedance source, up to 250mA can flow
through the part. The thermal shutdown circuit disables
the driver outputs when the internal temperature reaches
150°C and turns them back on when the temperature cools
to 130°C. If the outputs of two or more LTC491 drivers are
shorted directly, the driver outputs can not supply enough
current to activate the thermal shutdown. Thus, the ther-
mal shutdown circuit will not prevent contention faults
when two drivers are active on the bus at the same time.
APPLICATIO S I FOR ATIO
WUUU
Figure 9. Typical Connection
Figure 10. Line Repeater
LTC491 • F09
120
120
LTC491
DRIVER
RECEIVER
LTC491
DRIVER DX
RX
DX
RX 2
5
9
10
11
12
RECEIVER
9
10
11
12
5
2
1203
4
3
4
120
RECEIVER
LTC491
DRIVER
9 10 11 12
5432
DX RX
LTC491 • F10
120
LTC491
DRIVERDX
RX 2
5
9
10
11
12
RECEIVER DATA IN
DATA OUT
3
4
120
LTC491
8
491fa
U
S
A
O
PPLICATI
WU
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I FOR ATIO
Cables and Data Rate
The transmission line of choice for RS485 applications is
a twisted pair. There are coaxial cables (twinaxial) made
for this purpose that contain straight pairs, but these are
less flexible, more bulky, and more costly than twisted
pairs. Many cable manufacturers offer a broad range of
120 cables designed for RS485 applications.
Losses in a transmission line are a complex combination
of DC conductor loss, AC losses (skin effect), leakage and
AC losses in the dielectric. In good polyethylene cables
such as the Belden 9841, the conductor losses and
dielectric losses are of the same order of magnitude,
leading to relatively low over all loss (Figure 11).
When using low loss cables, Figure 12 can be used as a
guideline for choosing the maximum line length for a given
data rate. With lower quality PVC cables, the dielectric loss
factor can be 1000 times worse. PVC twisted pairs have
terrible losses at high data rates (>100kBs), and greatly
reduce the maximum cable length. At low data rates
however, they are acceptable and much more economical.
Cable Termination
The proper termination of the cable is very important.
If the cable is not terminated with it’s characteristic
impedance, distorted waveforms will result. In severe
cases, distorted (false) data and nulls will occur. A quick
look at the output of the driver will tell how well the cable
is terminated. It is best to look at a driver connected to the
end of the cable, since this eliminates the possibility of
getting reflections from two directions. Simply look at the
driver output while transmitting square wave data. If the
cable is terminated properly, the waveform will look like a
square wave (Figure 13).
If the cable is loaded excessively (47), the signal initially
sees the surge impedance of the cable and jumps to an
initial amplitude. The signal travels down the cable and is
reflected back out of phase because of the mistermination.
FREQUENCY (MH
Z
)
0.1
0.1
LOSS PER 100 ft (dB)
1.0
10
1.0 10 100
LTC491 • F11
DATA RATE (bps)
10k
10
CABLE LENGTH (ft)
100
1k
10k
100k 1M 10M
LTC491 • F12
2.5M
Figure 12. Cable Length vs Data Rate
Figure 11. Attenuation vs Frequency for Belden 9481
Figure 13. Termination Effects
Rt
DRIVERDX RECEIVER RX
Rt = 120
Rt = 47
Rt = 470
LTC491 • F13
PROBE HERE
9
LTC491
491fa
U
S
A
O
PPLICATI
WU
U
I FOR ATIO
When the reflected signal returns to the driver, the ampli-
tude will be lowered. The width of the pedestal is equal to
twice the electrical length of the cable (about 1.5ns/foot).
If the cable is lightly loaded (470), the signal reflects in
phase and increases the amplitude at the driver output. An
input frequency of 30kHz is adequate for tests out to 4000
feet of cable.
AC Cable Termination
Cable termination resistors are necessary to prevent un-
wanted reflections, but they consume power. The typical
differential output voltage of the driver is 2V when the
cable is terminated with two 120 resistors, causing
33mA of DC current to flow in the cable when no data is
being sent. This DC current is about 60 times greater than
the supply current of the LTC491. One way to eliminate the
unwanted current is by AC coupling the termination resis-
tors as shown in Figure 14.
The coupling capacitor must allow high-frequency energy
to flow to the termination, but block DC and low frequen-
cies. The dividing line between high and low frequency
depends on the length of the cable. The coupling capacitor
must pass frequencies above the point where the line
represents an electrical one-tenth wavelength. The value
of the coupling capacitor should therefore be set at 16.3pF
per foot of cable length for 120 cables. With the coupling
capacitors in place, power is consumed only on the signal
edges, and not when the driver output is idling at a 1 or 0
state. A 100nF capacitor is adequate for lines up to 4000
feet in length. Be aware that the power savings start to
decrease once the data rate surpasses 1/(120 × C).
Receiver Open-Circuit Fail-Safe
Some data encoding schemes require that the output of
the receiver maintains a known state (usually a logic 1)
when the data is finished transmitting and all drivers on the
line are forced into three-state. The receiver of the LTC491
has a fail-safe feature which guarantees the output to be in
a logic 1 state when the receiver inputs are left floating
(open-circuit). However, when the cable is terminated with
120, the differential inputs to the receiver are shorted
together, not left floating. Because the receiver has about
70mV of hysteresis, the receiver output will tend to main-
tain the last data bit received, but this is not guaranteed.
The termination resistors are used to generate a DC bias
which forces the receiver output to a known state; in the
case of Figure 15, a logic 0. The first method consumes
about 208mW and the second about 8mW. The lowest
power solution is to use an AC termination with a pull-up
resistor. Simply swap the receiver inputs for data proto-
cols ending in logic␣ 1.
LTC491 • F14
120
RECEIVER RX
C
C = LINE LENGTH (ft) x 16.3pF
Figure 14. AC Coupled Termination Figure 15. Forcing “O” When All Drivers are Off
140RECEIVER RX
5V
1.5k
RECEIVER RX
5V
110
130110130
LTC491 • F15
120
RECEIVER RX
C
5V 100k
1.5k
LTC491
10
491fa
U
S
A
O
PPLICATI
WU
U
I FOR ATIO
Fault Protection
All of LTC’s RS485 products are protected against ESD
transients up to 2kV using the human body model (100pF,
1.5k). However, some applications need more
protection. The best protection method is to connect a
bidirectional TransZorb
®
from each line side pin to ground
(Figure 16).
A TransZorb is a silicon transient voltage suppressor that
has exceptional surge handling capabilities, fast response
time, and low series resistance. They are available from
General Semiconductor Industries and come in a variety of
breakdown voltages and prices. Be sure to pick a break-
down voltage higher than the common mode voltage
Figure 16. ESD Protection with TransZorbs
LTC491 • F16
120
DRIVER
Z
Y
required for your application (typically 12V). Also, don’t
forget to check how much the added parasitic capacitance
will load down the bus.
TransZorb is a registered trademark of General Instruments, GSI
U
PACKAGE DESCRIPTIO
N Package
14-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
N14 1002
.020
(0.508)
MIN
.120
(3.048)
MIN
.130 ± .005
(3.302 ± 0.127)
.045 – .065
(1.143 – 1.651)
.065
(1.651)
TYP
.018 ± .003
(0.457 ± 0.076)
.005
(0.125)
MIN
.255 ± .015*
(6.477 ± 0.381)
.770*
(19.558)
MAX
31 24567
8910
11
1213
14
.008 – .015
(0.203 – 0.381)
.300 – .325
(7.620 – 8.255)
.325 +.035
–.015
+0.889
0.381
8.255
()
NOTE:
1. DIMENSIONS ARE INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.100
(2.54)
BSC
11
LTC491
491fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
S Package
14-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
U
PACKAGE DESCRIPTIO
1
N
234
.150 – .157
(3.810 – 3.988)
NOTE 3
14 13
.337 – .344
(8.560 – 8.738)
NOTE 3
.228 – .244
(5.791 – 6.197)
12 11 10 9
567
N/2
8
.016 – .050
(0.406 – 1.270)
.010 – .020
(0.254 – 0.508)× 45°
0° – 8° TYP
.008 – .010
(0.203 – 0.254)
S14 0502
.053 – .069
(1.346 – 1.752)
.014 – .019
(0.355 – 0.483)
TYP
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
.245
MIN
N
123 N/2
.160 ±.005
RECOMMENDED SOLDER PAD LAYOUT
.045 ±.005
.050 BSC
.030 ±.005
TYP
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
LTC491
12
491fa
LINEAR TECHNOLOGY CORPORATION 1992
LT/TP 0104 1K REV A • PRINTED IN USA
RS232 Receiver RS232 to RS485 Level Transistor with Hysteresis
TYPICAL APPLICATIO S
U
LTC491 • TA02
5.6k RECEIVER
RS232 IN
1/2 LTC491
RX
120
DRIVER
Y
Z
R = 220k
10k
RS232 IN
5.6k
LTC491 • TA03
HYSTERESIS = 10k
1/2 LTC491
VY - VZ
————
R
19k
————
R
RELATED PARTS
Linear Technolog y Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
FAX: (408) 434-0507
www.linear.com
PART NUMBER DESCRIPTION COMMENTS
LTC486/LTC487 Low Power Quad RS485 Drivers 110µA Supply Current
LTC488/LTC489 Low Power Quad RS485 Receivers 7mA Supply Current
LTC1480 3.3V Supply RS485 Transceiver Lower Supply Voltage
LTC1481 Low Power RS485 Transceiver with Shutdown Lowest Power
LTC1482 RS485 Transceiver with Carrier Detect ±15kV ESD, Fail-Safe
LTC1483 Low Power, Low EMI RS485 Transceiver Slew Rate Limited Driver Outputs, Lowest Power
LTC1484 RS485 Transceiver with Fail-Safe ±15kV ESD, MSOP Package
LTC1485 10Mbps RS485 Transceiver High Speed
LTC1518/LTC1519 52Mbps Quad RS485 Receivers Higher Speed, LTC488/LTC489 Pin-Compatible
LTC1520 LVDS-Compatible Quad Receiver 100mV Threshold, Low Channel-to-Channel Skew
LTC1535 2500V Isolated RS485 Transceiver Full-Duplex, Self-Powered Using External Transformer
LTC1685 52Mbps RS485 Transceiver Industry-Standard Pinout, 500ps Propagation Delay Skew
LTC1686/LTC1687 52Mbps Full-Duplex RS485 Transceiver LTC490/LTC491 Pin Compatible
LTC1688/LTC1689 100Mbps Quad RS485 Drivers Highest Speed, LTC486/LTC487 Pin Compatible
LTC1690 Full-Duplex RS485 Transceiver with Fail-Safe ±15kV ESD, LTC490 Pin Compatible
LT1785/LTC1785A ±60V Protected RS485 Transceivers ±15kV ESD, Fail-Safe (LT1785A)
LT1791/LTC1791A ±60V Protected Full-Duplex RS485 Transceivers ±15kV ESD, Fail-Safe (LT1791A), LTC491 Pin Compatible