LTC485CN8#PBF [Linear]
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| 型号： | LTC485CN8#PBF |
| 厂家： | 
Linear |
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LTC485
Low Power RS485
Interface Transceiver
U
FEATURES
DESCRIPTIO
The LTC®485 is a low power differential bus/line trans-
ceiverdesignedformultipointdatatransmissionstandard
RS485 applications with extended common mode range
(12V to –7V). It also meets the requirements of RS422.
■
Low Power: ICC = 300µA Typ
■
Designed for RS485 Interface Applications
■
Single 5V supply
–7V to 12V Bus Common Mode Range Permits
■
±7V Ground Difference Between Devices on the Bus
TheCMOSdesignofferssignificantpowersavingsoverits
bipolarcounterpartwithoutsacrificingruggednessagainst
overload of ESD damage.
■
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
Combined Impedance of a Driver Output and
Receiver Allows Up to 32 Transceivers on the Bus
70mV Typical Input Hysteresis
30ns Typical Driver Propagation Delays
with 5ns Skew
Pin Compatible with ±60V Protected LT1785 and
52Mbps LTC1685
■
■
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.
■
The LTC485 is fully specified over the commercial and
U
extended industrial temperature range.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
■
Low Power RS485/RS422 Transceiver
Level Translator
■
U
TYPICAL APPLICATIO
Driver Outputs
RO1
RE1
DE1
DI1
V
CC1
R
Rt
Rt
A
D
GND1
RO2
RE2
DE2
DI2
V
CC2
R
B
D
GND2
LTC485 • TA01
LTC485 • TA02
sn 485LTC485ffs
1
LTC485
W W W
U
W U
ABSOLUTE AXI U RATI GS
(Note 1)
/O
PACKAGE RDER I FOR ATIO
ORDER PART
NUMBER
Supply Voltage ....................................................... 12V
Control Input Voltages ................... –0.5V to VCC + 0.5V
Driver Input Voltage....................... –0.5V to VCC + 0.5V
Driver Output Voltage ........................................... ±14V
Receiver Input Voltage.......................................... ±14V
Receiver Output Voltages .............. –0.5V to VCC + 0.5V
Operating Temperature Range
LTC485I...................................... –40°C ≤ TA ≤ 85°C
LTC485C ......................................... 0°C ≤ TA ≤ 70°C
LTC485M (OBSOLETE) .......... –55°C ≤ TA ≤ 125°C
Lead Temperature (Soldering, 10 sec)................. 300°C
TOP VIEW
RO
RE
DE
DI
1
2
3
4
V
B
A
8
7
6
5
CC
R
LTC485CN8
LTC485CS8
LTC485IN8
LTC485IS8
D
GND
N8 PACKAGE
S8 PACKAGE
S8 PART MARKING
8-LEAD PLASTIC DIP 8-LEAD PLASTIC SOIC
TJMAX = 125°C, θJA = 100°C/ W (N)
TJMAX = 150°C, θJA = 150°C/ W (S)
485
485I
J8 PACKAGE
8-LEAD CERAMIC DIP
TJMAX = 155°C, θJA = 100°C/ W (J)
ORDER PART
NUMBER
LTC485CJ8
LTC485MJ8
OBSOLETE PACKAGE
Consider the N8 Package for Alternate Source
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V ±5%, unless otherwise noted. (Notes 2 and 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
V
Differential Driver Output Voltage (Unloaded)
Differential Driver Output Voltage (with Load)
I = 0
●
5
V
OD1
OD2
O
R = 50Ω (RS422)
R = 27Ω (RS485), Figure 1
●
●
2
1.5
V
V
5
∆V
OD
Change in Magnitude of Driver Differential
Output Voltage for Complementary States
R = 27Ω or R = 50Ω, Figure 1
●
0.2
V
V
Driver Common Mode Output Voltage
R = 27Ω or R = 50Ω, Figure 1
●
●
3
V
V
OC
∆
⏐V
⏐
OC
Change in Magnitude of Driver Common-Mode R = 27Ω or R = 50Ω, Figure 1
Output Voltage for Complementary States
0.2
V
V
Input High Voltage
Input Low Voltage
Input Current
DE, DI, RE
DE, DI, RE
DE, DI, RE
●
●
●
●
●
●
2
V
V
IH
IL
0.8
±2
I
I
µA
mA
mA
V
IN1
IN2
Input Current (A, B)
DE = 0, V = 0V
V
V
= 12V
= –7V
±1
CC
IN
IN
or 5.25V
–0.8
0.2
V
Differential Input Threshold Voltage
for Receiver
–7V ≤ V ≤ 12V
–0.2
3.5
TH
CM
∆V
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
V
= 0V
CM
●
●
●
●
70
mV
V
TH
V
V
I = –4mA, V = 200mV
O ID
OH
I = 4mA, V = –200mV
O
0.4
V
OL
ID
I
Three-State (High Impedance) Output
Current at Receiver
V
= Max, 0.4V ≤ V ≤ 2.4V
±1
µA
OZR
CC
O
R
IN
Receiver Input Resistance
–7V ≤ V ≤ 12V
●
12
kΩ
CM
sn485 LTC485ffs
2
LTC485
U
SWITCHI G CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C.VCC = 5V ±5%, unless otherwise noted. (Notes 2 and 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
500
300
100
100
MAX
900
500
250
250
85
UNITS
µA
µA
mA
mA
mA
ns
I
Supply Current
No Load, Pins 2, Outputs Enabled
3, 4 = 0V or 5V
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
CC
Outputs Disabled
I
I
I
t
t
t
Driver Short-Circuit Current, V
Driver Short-Circuit Current, V
Receiver Short-Circuit Current
Driver Input to Output
= HIGH
= LOW
V = –7V
O
35
35
7
OSD1
OSD2
OSR
OUT
V = 10V
O
OUT
0V ≤ V ≤ V
O
CC
R
DIFF
= 54Ω, C = C = 100pF,
10
10
30
30
5
50
PLH
L1
L2
(Figures 3 and 5)
Driver Input to Output
50
ns
PHL
Driver Output to Output
10
ns
SKEW
t , t
r
Driver Rise or Fall Time
3
15
40
40
40
40
90
90
13
20
20
20
20
25
ns
f
t
t
t
t
t
t
t
t
t
t
t
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
Receiver Input to Output
C = 100pF (Figures 4 and 6) S2 Closed
L
70
ns
ZH
ZL
LZ
HZ
C = 100pF (Figures 4 and 6) S1 Closed
L
70
ns
C = 15pF (Figures 4 and 6) S1 Closed
L
70
ns
C = 15pF (Figures 4 and 6) S2 Closed
L
70
ns
R
DIFF
= 54Ω, C = C = 100pF,
30
30
200
200
ns
PLH
PHL
SKD
ZL
L1
L2
(Figures 3 and 7)
ns
⏐t
– t ⏐ Differential Receiver Skew
PHL
ns
PLH
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable from Low
Receiver Disable from High
C
C
C
C
= 15pF (Figures 2 and 8) S1 Closed
= 15pF (Figures 2 and 8) S2 Closed
= 15pF (Figures 2 and 8) S1 Closed
= 15pF (Figures 2 and 8) S2 Closed
50
50
50
50
ns
RL
RL
RL
RL
ns
ZH
ns
LZ
ns
HZ
Note 1: Absolute maximum ratings are those beyond which the safety of
the device cannot be guaranteed.
Note 2: All currents into device pins are positive; all currents out ot device
pins are negative. All voltages are referenced to device ground unless
otherwise specified.
Note 3: All typicals are given for V = 5V and T = 25°C.
CC A
Note 4: The LTC485 is guaranteed by design to be functional over a supply
voltage range of 5V ±10%. Data sheet parameters are guaranteed over the
tested supply voltage range of 5V ±5%.
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Receiver Output Low Voltage
vs Output Current
Receiver Output High Voltage
vs Output Current
Receiver Output High Voltage
vs Temperature
36
32
28
24
20
16
12
8
–18
–16
–14
–12
–10
–8
4.8
4.6
4.4
4.2
4.0
3.8
3.6
3.4
3.2
T
= 25°C
T
= 25°C
I = 8mA
A
A
– 6
–4
4
–2
0
0
3.0
0
0.5
2.0
5
4
–50 –25
0
25
50
125
1.0
1.5
3
2
75 100
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
LTC485 • TPC01
LTC485 • TPC02
LTC485 • TPC03
sn 485LTC485ffs
3
LTC485
TYPICAL PERFOR A CE CHARACTERISTICS
U W
Receiver Output Low Voltage
vs Temperature
Driver Differential Output Voltage
vs Output Current
Driver Differential Output Voltage
vs Temperature
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
72
64
56
48
40
32
24
16
8
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
T
= 25°C
RI = 54Ω
I = 8mA
A
0
0
1.5
–50 –25
0
25
50
125
0
1
3
4
–50 –25
0
25
50
125
75 100
2
75 100
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
LTC485 • TPC03
LTC485 • TPC05
LTC485 • TPC06
Driver Output Low Voltage
vs Output Current
Driver Output High Voltage
vs Output Current
TTL Input Threshold
vs Temperature
90
80
70
60
50
40
30
20
10
–108
–96
–84
–72
–60
–48
–36
–24
–12
1.64
1.63
1.62
1.61
1.60
1.59
1.58
1.57
1.56
T
= 25°C
T
A
= 25°C
A
0
0
1.55
0
1
3
4
0
1
3
4
–50 –25
0
25
50
75 100 125
2
2
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
LTC485 • TPC07
LTC485 • TPC08
LTC485 • TPC09
Receiver
⏐tPLH – tPHL⏐
vs Temperature
Driver Skew vs Temperature
Supply Current vs Temperature
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
5.4
4.8
4.2
3.6
3.0
2.4
1.8
1.2
0.6
640
580
520
460
400
340
280
220
160
DRIVER ENABLED
DRIVER DISABLED
3.0
0
100
–50 –25
0
25
50
125
–50 –25
0
25
50
125
–50 –25
0
25
50
125
75 100
75 100
75 100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
LTC485 • TPC10
LTC485 • TPC11
LTC485 • TPC12
sn485 LTC485ffs
4
LTC485
U U
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PI FU CTIO S
DI (Pin 4): Driver Input. If the driver outputs are enabled
(DE high), then a low on DI forces the outputs A low and
B high. A high on DI with the driver outputs enabled will
force A high and B low.
RO (Pin 1): Receiver Output. If the receiver output is
enabled(RE low), then if A > B by 200mV, RO will be high.
If A < B by 200mV, then RO will be low.
RE (Pin 2): Receiver Output Enable. A low enables the
receiver output, RO. A high input forces the receiver
output into a high impedance state.
GND (Pin 5): Ground Connection.
A (Pin 6): Driver Output/Receiver Input.
B (Pin 7): Driver Output/Receiver Input.
DE (Pin 3): Driver Outputs Enable. A high on DE enables
the driver output. A and B, and the chip will function as a
line driver. A low input will force the driver outputs into a
high impedance state and the chip will function as a line
receiver.
V
CC (Pin 8): Positive Supply; 4.75 < VCC < 5.25.
TEST CIRCUITS
A
S1
S2
TEST POINT
C
R
1k
RECEIVER
OUTPUT
V
CC
V
OD
1k
RL
15pF
V
R
OC
LTC485 • F02
B
LTC485 • F01
Figure 1. Driver DC Test Load
Figure 2. Receiver Timing Test Load
3V
DE
S1
A
A
B
C
V
L1
CC
RO
DI
500Ω
OUTPUT
UNDER TEST
R
DIFF
B
S2
C
L2
RE
C
L
15pF
LTC485 • F02
LTC485 • F03
Figure 3. Driver/Receiver Timing Test Circuit
Figure 4. Driver Timing Test Load #2
U
W
W
SWITCHI G TI E WAVEFOR S
3V
DI
1.5V
f = 1MHz, t ≤ 10ns, t ≤ 10ns
1.5V
r
f
0V
B
1/2 V
O
t
t
PLH
PLH
V
O
A
t
t
SKEW
1/2 V
SKEW
O
90%
20%
V
O
80%
V
= V(A) – V(B)
0V
–V
DIFF
10%
O
LTC485 • F05
t
t
f
r
Figure 5. Driver Propagation Delays
sn 485LTC485ffs
5
LTC485
U
W
W
SWITCHI G TI E WAVEFOR S
3V
1.5V
f = 1MHz, t ≤ 10ns, t ≤ 10ns
1.5V
DI
A, B
A, B
r
f
0V
5V
t
t
LZ
ZL
2.3V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
0.5V
0.5V
V
OL
OH
0V
V
2.3V
t
LTC485 • F06
t
HZ
ZH
Figure 6. Driver Enable and Disable Times
V
OH
1.5V
1.5V
R
OUTPUT
V
OL
OD2
OD2
f = 1MHz, t ≤ 10ns, t ≤ 10ns
t
t
PLH
r
f
PHL
V
A, B
–V
0V
INPUT
LTC485 • F07
Figure 7. Receiver Propagation Delays
3V
0V
5V
1.5V
f = 1MHz, t ≤ 10ns, t ≤ 10ns
1.5V
RE
R
r
f
t
t
LZ
ZL
1.5V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
0.5V
0.5V
R
1.5V
0V
t
LTC485 • F08
t
HZ
ZH
Figure 8. Receiver Enable and Disable Times
U
U
FU CTIO TABLES
LTC485 Transmitting
LTC485 Receiving
OUTPUTS
INPUTS
INPUTS
OUTPUTS
LINE
RE
X
DE
1
DI
1
B
0
1
Z
Z
A
1
0
Z
Z
CONDITION
RE
0
DE
0
A – B
≥0.2V
R
No Fault
No Fault
X
1
X
1
0
0
0
≤–0.2V
0
X
0
X
X
0
0
Inputs Open
X
1
X
1
Fault
1
0
Z
sn485 LTC485ffs
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LTC485
U U
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APPLICATIO S I FOR ATIO
Basic Theory of Operation
(D1) or the N + /P-substrate diode (D2) respectively will
turn on and clamp the output to the supply. Thus, the
output stage is no longer in a high impedance state and is
not able to meet the RS485 common-mode range require-
ment. In addition, the large amount of current flowing
through either diode will induce the well known CMOS
latchup condition, which could destroy the device.
Previous RS485 transceivers have been designed using
bipolar technology because the common-mode range of
thedevicemustextendbeyondthesuppliesandthedevice
must be immune to ESD damage and latchup. Unfortu-
nately, the bipolar devices draw a large amount of supply
current, which is unacceptable for the numerous applica-
tions that require low power consumption. The LTC485 is
the first CMOS RS485/RS422 transceiver which features
ultra-lowpowerconsumptionwithoutsacrificingESDand
latchup immunity.
The LTC485 output stage of Figure 9 eliminates these
problems by adding two Schottky diodes, SD3 and SD4.
The Schottky diodes are fabricated by a proprietary modi-
fication to the standard N-well CMOS process. When the
output stage is operating normally, the Schottky diodes
are forward biased and have a small voltage drop across
them. When the output is in the high impedance state and
is driven above VCC or below ground, the parasitic diodes
D1 or D2 still turn on, but SD3 or SD4 will reverse bias and
prevent current from flowing into the N-well or the sub-
strate. Thus, the high impedance state is maintained even
with the output voltage beyond the supplies. With no
minority carrier current flowing into the N-well or sub-
strate, latchup is virtually eliminated under power-up or
power-down conditions.
The LTC485 uses a proprietary driver output stage, which
allows a common-mode range that extends beyond the
power supplies while virtually eliminating latchup and
providing excellent ESD protection. Figure 9 shows the
LTC485 output stage while Figure 10 shows a conven-
tional CMOS output stage.
When the conventional CMOS output stage of Figure 10
enters a high impedance state, both the P-channel (P1)
and the N-channel (N1) are turned off. If the output is then
driven above VCC or below ground, the P + /N-well diode
V
CC
V
CC
SD3
P1
P1
D1
D1
OUTPUT
OUTPUT
D2
LOGIC
LOGIC
SD4
N1
N1
D2
LTC485 • F10
LTC485 • F09
Figure 10. Conventional CMOS Output Stage
Figure 9. LTC485 Output Stage
sn 485LTC485ffs
7
LTC485
APPLICATIO S I FOR ATIO
U U
W
U
The LTC485 output stage will maintain a high impedance
state until the breakdown of the N-channel or P-channel is
reached when going positive or negative respectively. The
output will be clamped to either VCC or ground by a Zener
voltage plus a Schottky diode drop, but this voltage is way
beyond the RS485 operating range. This clamp protects
the MOS gates from ESD voltages well over 2000V.
BecausetheESDinjectedcurrentintheN-wellorsubstrate
consists of majority carriers, latchup is prevented by
careful layout techniques.
Propagation Delay
Many digital encoding schemes are dependent upon the
difference in the propagation delay times of the driver and
the receiver. Using the test circuit of Figure 13, Figures 11
and 12 show the typical LTC485 receiver propagation
delay.
The receiver delay times are:
⏐tPLH – tPHL⏐ = 9ns Typ, VCC = 5V
The driver skew times are:
Skew = 5ns Typ, VCC = 5V
10ns Max, VCC = 5V, TA = –40°C to 85°C
A
A
DRIVER
OUTPUTS
DRIVER
OUTPUTS
B
B
RECEIVER
RO
RECEIVER
RO
OUTPUT
OUTPUT
LTC485 • F11
LTC485 • F12
Figure 11. Receiver tPHL
Figure 12. Receiver tPLH
100pF
BR
RECEIVER
OUT
R
TTL IN
t , t < 6ns
D
R
100Ω
r
f
LTC485 • F13
100pF
Figure 13. Receiver Propagation Delay Test Circuit
sn485 LTC485ffs
8
LTC485
U U
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APPLICATIO S I FOR ATIO
LTC485 Line Length vs Data Rate
Figures 17 and 18 show that the LTC485 is able to
comfortably drive 4000 feet of wire at 110kHz.
The maximum line length allowable for the RS422/RS485
standard is 4000 feet.
RO
100Ω
C
A
B
TTL
OUT
COMMON MODE
VOLTAGE (A + B)/2
LTC485
LTC485
D
4000 FT 26AWG
TWISTED PAIR
NOISE
TTL
IN
GENERATOR
DI
LTC485 • F17
Figure 14. Line Length Test Circuit
Figure 17. System Common Mode Voltage at 110kHz
Using the test circuit in Figure 14, Figures 15 and 16 show
that with ~20VP-P common mode noise injected on the
line, The LTC485 is able to reconstruct the data stream at
the end of 4000 feet of twisted pair wire.
RO
COMMON MODE
VOLTAGE (A – B)
RO
DI
COMMON MODE
LTC485 • F18
VOLTAGE (A + B)/2
Figure 18. System Differential Voltage at 110kHz
DI
When specifying line length vs maximum data rate the
curve in Figure 19 should be used:
LTC485 • F15
Figure 15. System Common Mode Voltage at 19.2kHz
10k
1k
RO
DIFFERENTIAL
VOLTAGE A – B
100
10
DI
10k
100k
1M 2.5M
10M
MAXIMUM DATA RATE
LTC485 • F16
LTC485 • F19
Figure 16. System Differential Voltage at 19.2kHz
Figure 19. Cable Length vs Maximum Data Rate
sn 485LTC485ffs
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LTC485
TYPICAL APPLICATIO S
U
Typical RS485 Network
R
t
R
t
LTC485 • TA03
U
PACKAGE DESCRIPTIO
J8 Package
8-Lead CERDIP (Narrow .300 Inch, Hermetic)
(Reference LTC DWG # 05-08-1110)
0.405
(10.287)
MAX
CORNER LEADS OPTION
(4 PLCS)
0.005
(0.127)
MIN
6
5
4
8
7
2
0.023 – 0.045
(0.584 – 1.143)
HALF LEAD
OPTION
0.025
(0.635)
RAD TYP
0.220 – 0.310
(5.588 – 7.874)
0.045 – 0.068
(1.143 – 1.727)
FULL LEAD
OPTION
1
3
0.200
0.300 BSC
(5.080)
MAX
(0.762 BSC)
0.015 – 0.060
(0.381 – 1.524)
0.008 – 0.018
(0.203 – 0.457)
0° – 15°
0.045 – 0.065
(1.143 – 1.651)
0.125
3.175
MIN
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
0.014 – 0.026
(0.360 – 0.660)
0.100
(2.54)
BSC
J8 1298
OBSOLETE PACKAGE
sn485 LTC485ffs
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LTC485
U
PACKAGE DESCRIPTIO
N8 Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
0.400*
(10.160)
MAX
8
7
6
5
4
0.255 ± 0.015*
(6.477 ± 0.381)
1
2
3
0.130 ± 0.005
0.300 – 0.325
0.045 – 0.065
(3.302 ± 0.127)
(1.143 – 1.651)
(7.620 – 8.255)
0.065
(1.651)
TYP
0.009 – 0.015
(0.229 – 0.381)
0.125
0.020
(0.508)
MIN
(3.175)
MIN
+0.035
0.325
–0.015
0.018 ± 0.003
(0.457 ± 0.076)
0.100
(2.54)
BSC
+0.889
8.255
(
)
–0.381
N8 1098
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
7
5
8
6
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
SO8 1298
1
3
4
2
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
TYP
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
sn 485LTC485ffs
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-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
11
LTC485
RELATED PARTS
PART NUMBER
LTC486/LTC487
LTC488/LTC489
LTC490/LTC491
LTC1480
DESCRIPTION
COMMENTS
Low Power Quad RS485 Drivers
110µA Supply Current
Low Power Quad RS485 Receivers
Low Power Full-Duplex RS485 Transceivers
3.3V Supply RS485 Transceiver
7mA Supply Current
300µA Supply Current
Lower Supply Voltage
LTC1481
Low Power RS485 Transceiver with Shutdown
RS485 Transceiver with Carrier Detect
Low Power, Low EMI RS485 Transceiver
RS485 Transceiver with Fail-Safe
Lowest Power
LTC1482
±15kV ESD, Fail-Safe
LTC1483
Slew Rate Limited Driver Outputs, Lowest Power
±15kV ESD, MSOP Package
LTC1484
LTC1485
10Mbps RS485 Transceiver
High Speed
LTC1518/LTC1519
LTC1520
52Mbps Quad RS485 Receivers
Higher Speed, LTC488/LTC489 Pin-Compatible
100mV Threshold, Low Channel-to-Channel Skew
Full-Duplex, Self-Powered Using External Transformer
Industry-Standard Pinout, 500ps Propagation Delay Skew
LTC490/LTC491 Pin Compatible
Highest Speed, LTC486/LTC487 Pin Compatible
±15kV ESD, LTC490 Pin Compatible
±15kV ESD, Fail-Safe (LT1785A)
±15kV ESD, Fail-Safe (LT1791A)
LVDS-Compatible Quad Receiver
LTC1535
2500V Isolated RS485 Transceiver
52Mbps RS485 Transceiver
LTC1685
LTC1686/LTC1687
LTC1688/LTC1689
LTC1690
52Mbps Full-Duplex RS485 Transceiver
100Mbps Quad RS485 Drivers
Full-Duplex RS485 Transceiver with Fail-Safe
±60V Protected RS485 Transceivers
±60V Protected Full-Duplex RS485 Transceivers
LT1785/LTC1785A
LT1791/LTC1791A
sn485 LTC485ffs
LT/LCG 1101 1.5K REV F • PRINTED IN THE USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
12
●
●
© LINEAR TECHNOLOGY CORPORATION 1994
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
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