1
LTC1482
Low Power RS485 Transceiver
with Carrier Detect and
Receiver Fail-Safe
No Damage or Latchup to
±
15kV (Human Body
Model), IEC1000-4-2 Level 4 (
±
8kV) Contact and
Level 3 (
±
8kV) Air Discharge
Active Low Carrier Detect Output
Guaranteed High Receiver Output State for
Floating, Shorted or Terminated Inputs with
No Signal Present
Drives Low Cost Residential Telephone Wires
Low Power: I
CC
= 700µA Max with Driver Disabled
I
CC
= 900µA Max in Driver Mode Without Load
20µA Max Quiescent Current in Shutdown Mode
Single 5V Supply
7V to 12V Common Mode Range Permits ±7V
Ground Difference Between Devices on the Data Line
Maximum Data Rate of 4Mbps
Power Up/Down Glitch-Free Driver Outputs
Up to 32 Transceivers on the Bus
Available in 8-Lead MSOP, PDIP and SO Packages
The LTC
®
1482 is a low power RS485 compatible trans-
ceiver that offers an active low carrier detect output. The
open-drain carrier detect pin allows several transceivers
to share the same carrier detect line and can be used to
detect the insertion or removal of a driven RS485/RS422
cable.
Enhanced ESD protection allows the LTC1482 to with-
stand ±15kV (human body model), IEC-1000-4-2 level 4
(±8kV) contact and level 3 (±8kV) air discharge ESD
without latchup or damage.
The LTC1482 receiver stays alive at all times except in
shutdown. The supply current is a maximum of 700µA
and 900µA when the driver is disabled and enabled
respectively. In shutdown, the quiescent current of the
LTC1482 drops to a maximum of 20µA.
When the driver is disabled or the LTC1482 is in shut-
down, the driver outputs are three-stated and remain in
a high impedance state over the RS485 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 LTC1482 is fully specified over the commercial and
industrial temperature ranges and is available in 8-lead
MSOP, PDIP and SO packages.
Battery-Powered RS485/RS422 Applications
Low Power RS485/RS422 Transceiver
Level Translator
, LTC and LT are registered trademarks of Linear Technology Corporation.
RO1
CD1
DE1
DI1/SHDN1
R
V
CC1
LTC1482
GND1
B1
A1
B2
A2
120 120
D
V
CC2
GND2
1482 TA01
R
D
RO2
CD2
DE2
DI2/SHDN2
LTC1482
RS485 Interface
APPLICATIO S
U
FEATURES
TYPICAL APPLICATIO
U
DESCRIPTIO
U
Carrier Detect Output (2000 Foot STP Cable)
DE1 ↑↓ Dl1 = V
CC
1482 TA01a
DE2 = 0 Dl2 = V
CC
1k PULL-UP AT CD
DE1
A2
B2
CD2
2
LTC1482
ABSOLUTE MAXIMUM RATINGS
W
WW
U
(Note 1)
Supply Voltage (V
CC
)............................................... 6.5V
Control Input Voltages ................. 0.3V to (V
CC
+ 0.3V)
Carrier Detect Voltage ................................. 0.3V to 8V
Driver Input Voltage ..................... 0.3V to (V
CC
+ 0.3V)
Driver Output Voltages ................................. 7V to 10V
Receiver Input Voltages (Driver Disabled) .. 12V to 14V
Receiver Output Voltage............... 0.3V to (V
CC
+ 0.3V)
Junction Temperature .......................................... 125°C
Operating Temperature Range
LTC1482C ........................................ 0°C T
A
70°C
LTC1482I......................................40°C T
A
85°C
Storage Temperature Range .................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OD1
Differential Driver Output Voltage (Unloaded) I
OUT
= 0 V
CC
V
V
OD2
Differential Driver Output Voltage (with Load) R = 50 (RS422) 2V
R = 27 (RS485) Figure 1
1.5 5 V
R = 22, Figure 1
1.5 5 V
V
OD3
Differential Driver Output Voltage V
TST
= –7V to 12V, Figure 2 1.5 5 V
(with Common Mode)
V
OD
Change in Magnitude of Driver Differential R = 22, 27 or R = 50, Figure 1 0.2 V
Output Voltage for Complementary Output States V
TST
= –7V to 12V, Figure 2
V
OC
Driver Common Mode Output Voltage R = 22, 27 or R = 50, Figure 1 3V
|V
OC
| Change in Magnitude of Driver Common Mode R = 22, 27 or R = 50, Figure 1 0.2 V
Output Voltage for Complementary Output States
V
IH
Input High Voltage DE, DI/SHDN 2V
V
IL
Input Low Voltage DE, DI/SHDN 0.8 V
I
IN1
Input Current DE, DI/SHDN ±2 µA
I
IN2
Input Current (A, B) with Driver Disabled DE = 0, V
CC
= 0 or 5V, V
IN
= 12V 1.0 mA
DE = 0, V
CC
= 0 or 5V, V
IN
= –7V 0.8 mA
V
THRO
Differential Input Threshold Voltage for Receiver 7V V
CM
12V, DE = 0 0.20 0.015 V
ELECTRICAL CHARACTERISTICS
The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V ±5% (Notes 2 and 3) unless otherwise noted.
PACKAGE/ORDER INFORMATION
W
U
U
ORDER PART
NUMBER
ORDER PART
NUMBER
LTC1482CMS8 LTC1482CN8
LTC1482CS8
LTC1482IN8
LTC1482IS8
S8 PART MARKING
1482
1482I
MS8 PART MARKING
LTCB
T
JMAX
= 125°C, θ
JA
= 200°C/ W
1
2
3
4
RO
CD
DE
DI/SHDN
8
7
6
5
V
CC
B
A
GND
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C, θ
JA
= 130°C/ W (N8)
T
JMAX
= 125°C, θ
JA
= 135°C/W (S8)
1
2
3
4
8
7
6
5
TOP VIEW
RO
CD
DE
DI/SHDN
V
CC
B
A
GND
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
Consult factory for Military grade parts.
3
LTC1482
The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V ±5% (Notes 2 and 3) unless otherwise noted.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
THCD
Differential Input Threshold Voltage for CD = 1 7V V
CM
12V, DE = 0 0.20 0.20 V
V
TH
Receiver Input Hysteresis V
CM
= 0V, DE = 0 ±30 mV
V
OH
CD Output High Voltage I
OUT
= –10µA, (V
A
– V
B
) = 0V 3.4 V
RO Output High Voltage I
OUT
= –4mA, (V
A
– V
B
) = 200mV 3.5 V
V
OL
RO and CD Output Low Voltage I
OUT
= 4mA, (V
A
– V
B
) = –200mV 0.4 V
I
OZR
Three-State (High Impedance) Receiver Output V
CC
= Max, 0.4V V
OUT
2.4V ±1 µA
Current in Shutdown DI/SHDN = 0, DE = 0
R
IN
Receiver Input Resistance 7V V
CM
12V 12 22 k
I
CC
Supply Current No Load, Driver Enabled (DE = V
CC
) 580 900 µA
No Load, Driver Disabled (DE = 0)
430 700 µA
I
SHDN
Supply Current in Shutdown Mode DE = 0, DI = 0 10 20 µA
I
OSD1
Driver Short-Circuit Current, V
OUT
= High (Note 4) 7V V
OUT
10V 35 250 mA
I
OSD2
Driver Short-Circuit Current, V
OUT
= Low (Note 4) 7V V
OUT
10V 35 250 mA
I
OS
RO and CD Short-Circuit Current 0V V
OUT
V
CC
785mA
I
PULL-UP
CD Pull-Up Current CD = 0V 15 30 60 µA
SWITCHING CHARACTERISTICS
U
The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V ±5% (Notes 2 and 3) unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
PLH
Driver Input to Output R
DIFF
= 54, C
L1
= C
L2
= 100pF 10 28 60 ns
t
PHL
Driver Input to Output (Figures 4, 6) 10 30 60 ns
t
SKEW
Driver Output to Output 210 ns
t
r
, t
f
Driver Rise or Fall Time 31540 ns
t
ZH
Driver Enable to Output High C
L
= 100pF (Figures 5, 7) S2 Closed 40 70 ns
t
ZL
Driver Enable to Output Low C
L
= 100pF (Figures 5, 7) S1 Closed 40 100 ns
t
LZ
Driver Disable Time from Low C
L
= 15pF (Figures 5, 7) S1 Closed 40 70 ns
t
HZ
Driver Disable Time from High C
L
= 15pF (Figures 5, 7) S2 Closed 40 70 ns
t
ZH(SHDN)
Driver Enable from Shutdown to Output High C
L
= 100pF (Figures 5, 7) S2 Closed 40 100 ns
(Note 5)
t
ZL(SHDN)
Driver Enable from Shutdown to Output Low C
L
= 100pF (Figures 5, 7) S1 Closed 40 100 ns
t
HZ(SHDN)
Driver Disable on Shutdown from Output High C
L
= 15pF (Figures 5, 7) S2 Closed 40 100 ns
t
LZ(SHDN)
Driver Disable on Shutdown from Output Low C
L
= 15pF (Figures 5, 7) S1 Closed 40 100 ns
f
MAX
Maximum Data Rate (Note 6) 4 5 Mbps
t
PLH
Receiver Input to Output (Note 7) R
DIFF
= 54, C
L1
= C
L2
= 100pF, 30 138 200 ns
(Figures 4, 8)
t
PHL
Receiver Input to Output R
DIFF
= 54, C
L1
= C
L2
= 100pF, 30 122 200 ns
(Figures 4, 8)
t
SKD
|t
PLH
– t
PHL
| Differential Receiver Skew R
DIFF
= 54, C
L1
= C
L2
= 100pF, 16 ns
(Figures 4, 8)
t
CDH
Receiver Input to CD Output High (Note 7) R
DIFF
= 54, C
L1
= C
L2
= 100pF, 2900 5000 ns
(Figures 4, 10) DI/SHDN = V
CC
t
CDL
Receiver Input to CD Output Low (Note 7) R
DIFF
= 54, C
L1
= C
L2
= 100pF, 150 300 ns
(Figures 4, 10) DI/SHDN = V
CC

LTC1482CMS8#TRPBF

Mfr. #:
Manufacturer:
Analog Devices Inc.
Description:
RS-485 Interface IC L Pwr RS485 Tran w/ Carrier Detect & Rc
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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