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LTC1487CS8#PBF

P1-P3P4-P6P7-P8
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LTC1487
sn1487 1487fs
Ultra-Low Power RS485
with Low EMI, Shutdown
and High Input Impedance
S
F
EA
T
U
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D
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ESCRIPTIO
The LTC
®
1487 is an ultra-low power differential line trans-
ceiver designed with high impedance inputs allowing up to
256 transceivers to share a single bus. It meets the
requirements of RS485 and RS422. The LTC1487 features
output drivers with controlled slew rate, decreasing the
EMI radiated from the RS485 lines, and improving signal
fidelity with misterminated lines. The CMOS design offers
significant power savings without sacrificing ruggedness
against overload or ESD damage. Typical quiescent cur-
rent is only 80µA while operating and 1µA in shutdown.
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. I/O pins are protected against multiple
ESD strikes of over ±10kV using the Human Body Model.
The LTC1487 is fully specified over the commercial tem-
perature range and is available in 8-pin DIP and SO
packages.
■
High Input Impedance: Up to 256 Transceivers
on the Bus
■
Low Power: I
CC
= 120µA Max with Driver Disabled
■
I
CC
= 200µA Max with Driver Enabled, No Load
■
1µA Quiescent Current in Shutdown Mode
■
Controlled Slew Rate Driver for Reduced EMI
■
Single 5V Supply
■
ESD Protection to ±10kV On Receiver Inputs and
Driver outputs
■
–7V to 12V Common-Mode Range Permits ±7V
Ground Difference Between Devices on the Data Line
■
Thermal Shutdown Protection
■
Power Up/Down Glitch-Free Driver Outputs Permit
Live Insertion or Removal of Transceiver
■
Driver Maintains High Impedance in Three-State
or with the Power Off
■
Pin Compatible with the LTC485
U
A
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L
IC
AT
ITY
P
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CA
L
■
Battery-Powered RS485/RS422 Applications
■
Low Power RS485/RS422 Transceiver
■
Level Translator
U
S
A
O
PP
L
IC
AT
I
R
1
RO
120Ω
RE
DE
DI
2
3
7
6
7
6
4
1
2
3
4
D
R
D
RO
RE
DE
DI
LTC1487 • TA01
120Ω
330Ω
LTC1487 LTC1487
EQUIVALENT LOAD OF 256
LTC1487 TRANSCEIVERS
2000 FEET OF TWISTED-PAIR WIRE
4.7nF
DI
A
B
RO
RECEIVER INPUT
LTC1487 • TA02
, LTC and LT are registered trademarks of Linear Technology Corporation.
2
LTC1487
sn1487 1487fs
A
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W
A
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EXI T
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PACKAGE
/
O
RDER I FOR ATIO
(Note 1)
Supply Voltage (V
CC
) .............................................. 12V
Control Input Voltage..................... –0.5V to V
CC
+ 0.5V
Driver Input Voltage....................... –0.5V to V
CC
+ 0.5V
Driver Output Voltage ........................................... ±14V
Receiver Input Voltage.......................................... ±14V
Receiver Output Voltage ................ –0.5V to V
CC
+ 0.5V
Operating Temperature Range ............. 0°C ≤ T
A
≤ 70°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
S8 PART MARKING
Consult factory for Industrial and Military grade parts.
E
LECTR
IC
AL C CHARA TERIST
ICS
0°C ≤ T
A
≤ 70°C, V
CC
= 5V (Notes 2, 3) unless otherwise noted.
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 = 50Ω (RS422) ● 2.0 V
R = 27Ω (RS485), Figure 1
● 1.5 5 V
∆V
OD
Change in Magnitude of Driver Differential Output R = 27Ω or R = 50Ω, Figure 1 ● 0.2 V
Voltage for Complementary Output States
V
OC
Driver Common-Mode Output Voltage R = 27Ω or R = 50Ω, Figure 1 ● 3V
∆V
OC
Change in Magnitude of Driver Common-Mode R = 27Ω or R = 50Ω, Figure 1 ● 0.2 V
Output Voltage for Complementary Output States
V
IH
Input High Voltage DE, DI, RE ● 2V
V
IL
Input Low Voltage DE, DI, RE ● 0.8 V
I
IN1
Input Current DE, DI, RE ● ±2 µA
I
IN2
Input Current (A, B) DE = 0, V
CC
= 0V or 5.25V, V
IN
= 12V ● 0.30 mA
DE = 0, V
CC
= 0V or 5.25V, V
IN
= –7V ● –0.15 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 ● 45 mV
V
OH
Receiver Output High Voltage I
O
= –4mA, V
ID
= 200mV ● 3.5 V
V
OL
Receiver Output Low Voltage I
O
= 4mA, V
ID
= –200mV ● 0.4 V
I
OZR
Three-State (High Impedance) Output V
CC
= Max, 0.4V ≤ V
O
≤ 2.4V ● ±1 µA
Current at Receiver
R
IN
Receiver Input Resistance –7V ≤ V
CM
≤ 12V ● 70 96 kΩ
I
CC
Supply Current No Load, Output Enabled ● 120 200 µA
No Load, Output Disabled
● 80 120 µA
I
SHDN
Supply Current in Shutdown Mode DE = 0V, RE = V
CC
110µA
I
OSD1
Driver Short-Circuit Current, V
OUT
= HIGH –7V ≤ V
O
≤ 12V ● 35 250 mA
I
OSD2
Driver Short-Circuit Current, V
OUT
= LOW –7V ≤ V
O
≤ 12V ● 35 250 mA
I
OSR
Receiver Short-Circuit Current 0V ≤ V
O
≤ V
CC
● 785mA
T
JMAX
= 125°C, θ
JA
= 130°C/W (N8)
T
JMAX
= 125°C, θ
JA
= 150°C/ W (S8)
1487
LTC1487CN8
LTC1487CS8
1
2
3
4
8
7
6
5
TOP VIEW
V
CC
B
A
GND
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
R
D
RO
RE
DE
DI
3
LTC1487
sn1487 1487fs
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
PLH
Driver Input to Output R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF, ● 150 1200 ns
t
PHL
Driver Input to Output ● 150 1200 ns
t
SKEW
Driver Output to Output ● 250 600 ns
t
r
, t
f
Driver Rise or Fall Time ● 150 1200 ns
t
ZH
Driver Enable to Output High C
L
= 100pF (Figures 4, 6), S2 Closed ● 100 1500 ns
t
ZL
Driver Enable to Output Low C
L
= 100pF (Figures 4, 6), S1 Closed ● 100 1500 ns
t
LZ
Driver Disable Time from Low C
L
= 15pF (Figures 4, 6), S1 Closed ● 150 1500 ns
t
HZ
Driver Disable Time from High C
L
= 15pF (Figures 4, 6), S2 Closed ● 150 1500 ns
t
PLH
Receiver Input to Output R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF, ● 30 140 250 ns
t
PHL
Receiver Input to Output ● 30 140 250 ns
t
SKD
t
PLH
– t
PHL
Differential Receiver Skew ● 13 ns
t
ZL
Receiver Enable to Output Low C
RL
= 15pF (Figures 2, 8), S1 Closed ● 20 50 ns
t
ZH
Receiver Enable to Output High C
RL
= 15pF (Figures 2, 8), S2 Closed ● 20 50 ns
t
LZ
Receiver Disable from Low C
RL
= 15pF (Figures 2, 8), S1 Closed ● 20 50 ns
t
HZ
Receiver Disable from High C
RL
= 15pF (Figures 2, 8), S2 Closed ● 20 50 ns
f
MAX
Maximum Data Rate ● 250 kbps
t
SHDN
Time to Shutdown DE = 0, RE = ● 50 200 600 ns
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 = 50Ω (RS422) ● 2.0 V
R = 27Ω (RS485), Figure 1
● 1.5 5 V
V
OC
Driver Common-Mode Output Voltage R = 27Ω or R = 50Ω, Figure 1 ● 3V
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 ● 45 mV
I
CC
Supply Current No Load, Output Enabled ● 120 200 µA
No Load, Output Disabled
● 80 120 µA
I
SHDN
Supply Current in Shutdown Mode DE = 0V, RE = V
CC
110µA
t
PLH
Driver Input to Output R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF, ● 150 1200 ns
t
PHL
Driver Input to Output ● 150 1200 ns
t
SKEW
Driver Output to Output ● 100 600 ns
t
r
, t
f
Driver Rise or Fall Time ● 150 2000 ns
t
PLH
Receiver Input to Output R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF, ● 30 140 250 ns
t
PHL
Receiver Input to Output ● 30 140 250 ns
t
SKD
t
PLH
– t
PHL
Differential Receiver Skew ● 13 ns
f
MAX
Maximum Data Rate ● 250 kbps
E
LECTR
IC
AL C CHARA TERIST
ICS
–40°C ≤ T
A
≤ 85°C, V
CC
= 5V (Note 4) unless otherwise noted.
(Figures 3, 5)
(Figures 3, 7)
0°C ≤ T
A
≤ 70°C, V
CC
= 5V (Notes 2, 3) unless otherwise noted.
SWITCHI G CHARACTERISTICS
U
(Figures 3, 5)
(Figures 3, 7)
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LTC1487CS8#PBF

Mfr. #:
Buy LTC1487CS8#PBF
Manufacturer:
Analog Devices Inc.
Description:
RS-485 Interface IC Ultra-L Pwr RS485 w/ L EMI, SD & Hi In I
Lifecycle:
New from this manufacturer.
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