LT1485 [Linear]
Differential Bus Transceiver; 差动总线收发器
| 型号： | LT1485 |
| 厂家： | 
Linear |
| 描述： | Differential Bus Transceiver |
| 文件： | 总12页 (文件大小：258K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC1485
Differential Bus Transceiver
U
DESCRIPTIO
EATURE
ESD Protection over
Low Power: ICC = 1.8mA Typ
28ns Typical Driver Propagation Delays with
4ns Skew
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
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
60mV Typical Input Hysteresis
S
F
■
■
■
±
10kV
The LTC®1485 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.
■
■
■
The CMOS with Schottky 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. I/O pins are protected against
multiple ESD strikes of over ±10kV.
■
■
■
Pin Compatible with the SN75176A, DS75176A, and
SN75LBC176
The receiver has a fail-safe feature which guarantees a
high output state when the inputs are left open.
O U
BothACandDCspecificationsareguaranteedfrom– 40°C
to 85°C and 4.75V to 5.25V supply voltage range.
PPLICATI
S
A
■
Low Power RS485/RS422 Transceiver
Level Translator
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
U
O
TYPICAL APPLICATI
5V
DE
5V
DE
3
8
3
8
LTC1485
LTC1485
6
7
6
4
1
4
1
120Ω
4000 FT 24 GAUGE TWISTED PAIR
DI
120Ω
DI
DRIVER
DRIVER
7
RO
RO
RECEIVER
RECEIVER
5
2
5
2
RE
RE
1485 TA01
1
LTC1485
W W W
U
/O
ABSOLUTE AXI U RATI GS
(Note 1)
PACKAGE RDER I FOR ATIO
ORDER PART
TOP VIEW
Supply Voltage (VCC) .............................................. 12V
Control Input Voltages ................... – 0.5V to VCC + 0.5V
Control Input Currents ........................ – 50mA to 50mA
Driver Input Voltages ..................... – 0.5V to VCC + 0.5V
Driver Input Currents .......................... – 25mA to 25mA
Driver Output Voltages ......................................... ±14V
Receiver Input Voltages ........................................ ±14V
Receiver Output Voltages .............. – 0.5V to VCC + 0.5V
Operating Temperature Range
LTC1485C............................................... 0°C to 70°C
LTC1485I .......................................... – 40°C to 85°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec.)................ 300°C
NUMBER
RO
RE
DE
DI
1
2
3
4
8
7
6
5
V
B
CC
R
LTC1485CN8
LTC1485IN8
LTC1485CS8
LTC1485IS8
A
D
GND
N8 PACKAGE
8-LEAD PLASTIC DIP 8-LEAD PLASTIC SOIC
S8 PACKAGE
TJMAX = 125°C, θJA = 100°C/ W (N)
TJMAX = 150°C, θJA = 150°C/ W (S)
S8 PART MARKING
1485
1485I
Consult factory for Military grade parts.
DC ELECTRICAL CHARACTERISTICS
VCC = 5V (Notes 2, 3), unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
I = 0
R = 50Ω, (RS422)
MIN
TYP
5
MAX
V
UNITS
V
V
Differential Driver Output Voltage (Unloaded)
Differential Driver Output Voltage (With Load)
●
OD1
OD2
O
●
●
2
1.5
V
V
R = 27Ω, (RS485) (Figure 1)
5
∆V
Change in Magnitude of Driver Differential
Output Voltage for Complementary Output States
R = 27Ω or R = 50Ω (Figure 1)
●
0.2
V
OD
V
∆|V
Driver Common-Mode Output Voltage
Change in Magnitude of Driver Common-Mode
Output Voltage for Complementary Output States
R = 27Ω or R = 50Ω (Figure 1)
R = 27Ω or R = 50Ω (Figure 1)
●
●
3
0.2
V
V
OC
|
OC
V
V
Input High Voltage
Input Low Voltage
Input Current
DI, DE, RE
DI, DE, RE
DI, DE, RE
●
●
●
2.0
V
V
µA
mA
mA
INH
INL
0.8
±2
1.0
– 0.8
I
I
IN1
IN2
Input Current (A, B)
V
V
= 0V or 5.25V, V = 12V
= 0V or 5.25V, V = –7V
●
●
CC
CC
IN
IN
V
∆V
Differential Input Threshold Voltage for Receiver
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State Output Current at Receiver
Supply Current
– 7V ≤ V ≤ 12V
●
●
●
●
●
– 0.2
3.5
0.2
V
mV
V
V
µA
TH
CM
V
= 0V
CM
60
TH
V
V
I = – 4mA, V = 0.2V
O ID
OH
I = 4mA, V = – 0.2V
0.4
±1
OL
OZR
CC
O
ID
I
I
V
= Max 0.4V ≤ V ≤ 2.4V
CC
O
No Load; DI = GND or V
Outputs Enabled
CC
●
●
1.8
1.7
2.3
2.3
mA
mA
Outputs Disabled
R
Receiver Input Resistance
– 7V ≤ V ≤ 12V
●
●
●
●
12
7
kΩ
mA
mA
mA
IN
CM
I
I
I
Driver Short-Circuit Current, V
Driver Short-Circuit Current, V
Receiver Short-Circuit Current
= High
= Low
V = –7V
250
250
85
OSD1
OSD2
OSR
OUT
O
V = 10 V
OUT
O
0V ≤ V ≤ V
O
CC
2
LTC1485
U
SWI I
TCH G CHARACTERISTICS
VCC = 5V (Notes 2, 3), unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
= 54Ω, C = C = 100pF
(Figures 2, 5)
MIN
10
TYP
30
MAX
50
UNITS
t
t
t
Driver Input to Output
Driver Input to Output
Driver Output to Output
Driver Rise or Fall Time
R
DIFF
●
●
●
●
ns
PLH
L1
L2
R
DIFF
= 54Ω, C = C = 100pF
10
5
30
4
50
10
25
ns
ns
ns
PHL
L1
L2
(Figures 2, 5)
R
DIFF
= 54Ω, C = C = 100pF
SKEW
L1
L2
(Figures 2, 5)
t , t
r
R
DIFF
= 54Ω, C = C = 100pF
15
f
L1
L2
(Figures 2, 5)
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, 6) S2 Closed
●
●
●
●
●
●
●
40
40
40
40
25
30
5
70
70
70
70
50
55
15
ns
ns
ns
ns
ns
ns
ns
ZH
ZL
LZ
HZ
L
C = 100pF (Figures 4, 6) S1 Closed
L
C = 15pF (Figures 4, 6) S1 Closed
L
C = 15pF (Figures 4, 6) S2 Closed
L
R
DIFF
R
DIFF
R
DIFF
= 54Ω, C = C = 100pF (Figures 2, 7)
= 54Ω, C = C = 100pF (Figures 2, 7)
L1 L2
= 54Ω, C = C = 100pF (Figures 2, 7)
L1 L2
15
20
PLH
L1
L2
Receiver Input to Output
PHL
| t
– t
|
SKEW
PLH
PHL
Differential Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable from Low
Receiver Disable from High
t
t
t
t
C = 15pF (Figures 3, 8) S1 Closed
●
●
●
●
30
30
30
30
45
45
45
45
ns
ns
ns
ns
ZL
ZH
LZ
HZ
L
C = 15pF (Figures 3, 8) S2 Closed
L
C = 15pF (Figures 3, 8) S1 Closed
L
C = 15pF (Figures 3, 8) S2 Closed
L
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.
The
range.
●
denotes specifications which apply over the operating temperature
Note 1: Absolute Maximum Ratings are those values beyond which the
safety of the device cannot be guaranteed.
Note 3: All typicals are given for V = 5V and T = 25°C.
CC
A
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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
–18
–16
–14
–12
–10
4.8
4.6
4.4
I = 8mA
T
A
= 25°C
T
A
= 25°C
4.2
4.0
3.8
3.6
3.4
3.2
3.0
16
12
8
–8
–6
–4
–2
4
0
0
0
0.5
1.5
OUTPUT VOLTAGE (V)
5
4
3
–50 –25
0
25
50
75 100 125
1.0
2.0
2
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
1485 G01
1485 G02
1485 G03
3
LTC1485
TYPICAL PERFOR A CE CHARACTERISTICS
U W
Driver Differential Output Voltage
vs Temperature
Receiver Output Low Voltage
vs Temperature
Driver Differential Output Voltage
vs Output Current
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
I = 8mA
T
A
= 25°C
R
=54Ω
L
64
48
32
16
2.4
2.2
2.0
1.8
0
1.6
0
0
1
3
–50 –25
0
25
50
75 100 125
–50 –25
0
25
50
75 100 125
2
4
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
1485 G05
1485 G06
1485 G04
Driver Output Low Voltage vs
Output Current
Driver Output High Voltage vs
Output Current
TTL Input Threshold vs
Temperature
T
A
= 25°C
T = 25°C
A
80
60
40
20
–96
–72
–48
–24
1.63
1.61
1.59
1.57
0
0
1.55
0
1
3
0
1
3
2
4
2
4
–50 –25
0
25
50
75 100 125
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
1485 G07
1485 G08
1485 G09
Receiver | tPLH – tPHL| vs
Temperature
Driver Skew vs Temperature
Supply Current vs Temperature
5
4
3
2
5
4
3
2
1.8
1.7
1.6
1.5
DRIVER ENABLED
DRIVER DISABLED
1
1
1.4
–50 –25
0
25
50
75 100 125
–50 –25
0
25
50
75 100 125
–50 –25
0
25
50
75 100 125
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
1485 G10
1485 G11
1485 G12
4
LTC1485
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 driver outputs A low
and B high. A high on DI 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.
GND (Pin 5): Ground Connection.
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.
A (Pin 6): Driver Output/Receiver Input.
B (Pin 7): Driver Output/Receiver Input.
DE (Pin 3): Driver Output Enable. A high on DE enables the
driver outputs, A and B. A low input will force the driver
outputs into a high impedance state.
V
CC (Pin 8): Positive Supply. 4.75V ≤ VCC ≤ 5.25V.
TEST CIRCUITS
A
R
V
OD2
A
A
B
C
C
L1
R
DI
R
DIFF
RO
DRIVER
B
RECEIVER
V
OC
B
15pF
L2
1485 F02
1485 F01
Figure 1. Driver DC Test Load
Figure 2. Driver/Receiver Timing Test Circuit
S1
1k
S1
RECEIVER
OUTPUT
V
V
CC
CC
500Ω
OUTPUT
UNDER TEST
C
L
1k
S2
S2
C
L
1485 F04
1485 F03
Figure 4. Driver Timing Test Load
Figure 3. Receiver Timing Test Load
5
LTC1485
U
W
W
SWITCHI G TI E WAVEFOR S
3V
f = 1MHz; t ≤ 10ns; t ≤ 10ns
r
f
1.5V
DI
1.5V
0V
t
PLH
t
PHL
V
O
90%
90%
V
– V
B
50%
50%
10%
A
10%
–V
O
t
t
r
f
B
A
1/2 V
1/2 V
O
O
V
O
t
t
SKEW
SKEW
1485 F05
Figure 5. Driver Propagation Delays
3V
0V
f = 1MHz; t ≤ 10ns; t ≤ 10ns
r
f
1.5V
ZL
1.5V
DE
t
t
LZ
5V
A,B
2.3V
2.3V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
0.5V
V
OL
V
OH
0.5V
A,B
0V
1485 F06
t
ZH
t
HZ
Figure 6. Driver Enable and Disable Times
INPUT
V
OD2
f = 1MHz; t ≤ 10ns; t ≤ 10ns
r
f
0V
0V
V
A
– V
B
–V
OD2
t
PLH
t
PHL
OUTPUT
V
OH
1.5V
1.5V
RO
V
OL
1485 F07
Figure 7. Receiver Propagation Delays
6
LTC1485
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W
W
SWITCHI G TI E WAVEFOR S
3V
1.5V
RE
1.5V
LZ
f = 1MHz; t ≤ 10ns; t ≤ 10ns
r
f
0V
t
ZL
t
5V
RO
1.5V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
0.5V
0.5V
V
OL
V
OH
1.5V
RO
0V
1485 F08
t
ZH
t
HZ
Figure 8. Receiver Enable and Disable Times
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PPLICATI
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S I FOR ATIO
Typical Application
ends with a resistor equal to their characteristic imped-
ance, typically 120Ω. The input impedance of a receiver is
typically20ktoGND, or0.6unitRS485load, soinpractice
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.
A typical connection of the LTC1485 is shown in Figure 9.
Two twisted pair wires connect up to 32 driver/receiver
pairs for half 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
LTC1485
1
LTC1485
1
RX
DX
RECEIVER
RX
DX
RECEIVER
2
3
2
3
7
4
4
DRIVER
120Ω
120Ω
DRIVER
8
LTC1485
1485 F09
1
2
3
RX
DX
RECEIVER
7
8
4
DRIVER
Figure 9. Typical Connection
7
LTC1485
PPLICATI
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A
S I FOR ATIO
10
Thermal Shutdown
The LTC1485 has a thermal shutdown feature which
protects the part from excessive power dissipation. If the
outputs of the driver are accidentally 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 LTC1485
drivers are shorted directly, the driver outputs can not
supply enough current to activate the thermal shutdown.
Thus, the thermal shutdown circuit will not prevent con-
tention faults when two drivers are active on the bus at the
same time.
1
0.1
0.1
1
10
100
FREQUENCY (MHz)
1485 F10
Figure 10. Attenuation vs Frequency for Belden 9481
10k
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
120Ω cables designed for RS485 applications.
1k
100
10
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 dielec-
tric losses are of the same order of magnitude, leading to
relatively low overall loss (Figure 10).
2.5M
10k
100k
DATA RATE (bps)
1M
10M
1485 F11
Figure 11. Cable Length vs Data Rate
end of the cable, since this eliminates the possibility of
gettingreflectionsfromtwodirections.Simplylookatthe
driver output while transmitting square wave data. If the
cable is terminated properly, the waveform will look like
a square wave (Figure12).
When using low loss cables, Figure 11 can be used as a
guidelineforchoosingthemaximumlinelengthforagiven
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, theyareacceptableandmuchmoreeconomical.
If the cable is loaded excessively (47Ω) the signal initially
sees the surge impedance of the cable and jumps to an
initial amplitude. The signal travels down the cable and is
reflectedbackoutofphasebecauseofthemistermination.
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 (470Ω) 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.
Cable Termination
The proper termination of the cable is very important. If
the cable is not terminated with its characteristic imped-
ance, 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
8
LTC1485
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PPLICATI
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PROBE HERE
of the coupling capacitor should therefore be set at 16.3pF
perfootofcablelengthfor120Ω cables. Withthecoupling
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.A100nFcapacitorisadequateforlinesupto400feet
in length. Be aware that the power savings start to de-
crease once the data rate surpasses 1/(120Ω • C).
R
DX
Rt = 120Ω
Rt = 47Ω
RX
DRIVER
RECEIVER
t
Receiver Open-Circuit Fail-Safe
Some data encoding schemes require that the output of
the receiver maintains a known state (usually a logic 1)
whenthedataisfinishedtransmittingandalldriversonthe
lineareforcedintothree-state.ThereceiveroftheLTC1485
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).
Rt = 470Ω
1485 F12
Figure 12. Termination Effects
If the receiver output must be forced to a known state, the
circuits of Figure 14 can be used.
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 120Ω resistors, causing
33mA of DC current to flow in the cable when no data is
being sent. This DC current is about 10 times greater than
the supply current of the LTC1485. One way to eliminate
the unwanted current is by AC-coupling the termination
resistors as shown in Figure 13.
5V
110Ω
130Ω
130Ω
110Ω
RECEIVER
RX
5V
1.5k
120Ω
RECEIVER
RX
120Ω
RECEIVER
RX
1.5k
C
1485 F13
C = LINE LENGTH (FT) • 16.3pF
5V
Figure 13. AC-Coupled Termination
100k
C
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
RECEIVER
RX
120Ω
1485 F14
Figure 14. Forcing “0” When All Drivers Are Off
9
LTC1485
PPLICATI
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The termination resistors are used to generate a DC bias
which forces the receiver output to a known state, in this
case 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 protocols ending in
logic 1.
A
B
DRIVER
120Ω
1485 F15
Fault Protection
Figure 15. ESD Protection with TransZorbs
All of LTC’s RS485 products are protected against ESD
transients up to 2kV using the human body model
(100pF, 1.5kΩ). However, some applications need more
protection. The best protection method is to connect a
bidirectionalTransZorb® fromeachlinesidepintoground
(Figure 15).
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
breakdown voltage higher than the common-mode volt-
age required for your application (typically 12V). Also,
don’t forget to check how much the added parasitic
capacitance will load down the bus.
A TransZorb is a silicon transient voltage suppressor that
has exceptional surge handling capabilities: fast response
TransZorb is a registered trademark of General Instruments, GSI
U
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TYPICAL APPLICATI S
RS232 Receiver
RS232
IN
RX
5.6k
RECEIVER
1485 TA02
RS232 to RS485 Level Translator with Hysteresis
220k
A
10k
RS232
120Ω
DRIVER
IN
5.6k
HYSTERESIS = 10k •
1485 TA03
B
V
– V /R ≈ 19 (kΩ • VOLT)/R
B
A
10
LTC1485
U
Dimensions in inches (millimeters) unless otherwise noted.
PACKAGE DESCRIPTIO
N8 Package
8-Lead Plastic DIP
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
0.015
(0.380)
MIN
(3.175)
MIN
+0.025
0.045 ± 0.015
(1.143 ± 0.381)
0.325
–0.015
+0.635
8.255
(
)
–0.381
0.100 ± 0.010
(2.540 ± 0.254)
0.018 ± 0.003
(0.457 ± 0.076)
N8 0694
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm).
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 circuits as described herein will not infringe on existing patent rights.
11
LTC1485
U
Dimensions in inches (millimeters) unless otherwise noted.
PACKAGE DESCRIPTIO
S8 Package
8-Lead Plastic SOIC
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)
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)
SO8 0294
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC486
Quad RS485 Driver
Fits 75172 Pinout, Only 110µA I
Q
Q
LTC488
Quad RS485 Receiver
Fits 75173 Pinout, Only 7mA I
Q
LTC490
Full Duplex RS485 Transceiver
Ultra-Low Power Half Duplex RS485 Transceiver
Fits 75179 Pinout, Only 300µA I
Fits 75176 Pinout, 80µA I
LTC1481
Q
LT/GP 0795 2K REV A • PRINTED IN THE USA
LINEAR TECHNOLOGY CORPORATION 1995
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
12
●
●
(408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977
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