Datasheet LTC1485 Datasheet (Linear Technology)

LTC1485

Differential Bus Transceiver

EATU

F

■

ESD Protection over ±10kV

■

Low Power: ICC = 1.8mA Typ

■

28ns Typical Driver Propagation Delays with

RE

S

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

■

Pin Compatible with the SN75176A, DS75176A, and
SN75LBC176

U

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PPLICATI

A

■

Low Power RS485/RS422 Transceiver

■

Level Translator

S

DUESCRIPTIO

The LTC®1485 is a low power differential bus/line trans­ceiver 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 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.

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 – 40°C
to 85°C and 4.75V to 5.25V supply voltage range.

, LTC and LT are registered trademarks of Linear Technology Corporation.

A

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PPLICATITYPICAL

5V

8

6

7

5

DRIVER

RECEIVER

RE

DE

3

4

DI

1

RO

2

1485 TA01

RO

DE

3

4

DI

DRIVER

1

RECEIVER

RE

5V

8

LTC1485 LTC1485

2

6

120Ω

7

4000 FT 24 GAUGE TWISTED PAIR

5

120Ω

1

LTC1485

WU

U

PACKAGE

/

O

RDER I FOR ATIO

W

O

A

(Note 1)

LUTEXI T

S

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

A

WUW

ARB

U
G

I

S

TOP VIEW

1

RO

2

RE

3

DE

45

DI

N8 PACKAGE

8-LEAD PLASTIC DIP

T

= 125°C, θJA = 100°C/ W (N)

JMAX

= 150°C, θJA = 150°C/ W (S)

T

JMAX

8

R

7

D

6

S8 PACKAGE

8-LEAD PLASTIC SOIC

V

CC

B
A

GND

ORDER PART

NUMBER

LTC1485CN8
LTC1485IN8
LTC1485CS8
LTC1485IS8

S8 PART MARKING

1485
1485I

LTC1485I .......................................... – 40°C to 85°C

Storage Temperature Range ................ –65°C to 150°C

Consult factory for Military grade parts.

Lead Temperature (Soldering, 10 sec.)................ 300°C

LECTRICAL C CHARA TERIST

E

V

= 5V (Notes 2, 3), unless otherwise noted.

CC

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OD1

V

OD2

∆V

OD

V

OC

∆|VOC| Change in Magnitude of Driver Common-Mode R = 27Ω or R = 50Ω (Figure 1) ● 0.2 V

V

INH

V

INL

I

IN1

I

IN2

V

TH

∆V

TH

V

OH

V

OL

I

OZR

I

CC

R

IN

I

OSD1

I

OSD2

I

OSR

Differential Driver Output Voltage (Unloaded) IO = 0 ● 5V
Differential Driver Output Voltage (With Load) R = 50Ω, (RS422) ● 2V

Change in Magnitude of Driver Differential R = 27Ω or R = 50Ω (Figure 1) ● 0.2 V
Output Voltage for Complementary Output States

Driver Common-Mode Output Voltage R = 27Ω or R = 50Ω (Figure 1) ● 3V

Output Voltage for Complementary Output States
Input High Voltage DI, DE, RE ● 2.0 V
Input Low Voltage DI, DE, RE ● 0.8 V
Input Current DI, DE, RE ● ±2 µA
Input Current (A, B) VCC = 0V or 5.25V, VIN = 12V ● 1.0 mA

Differential Input Threshold Voltage for Receiver – 7V ≤ VCM ≤ 12V ● – 0.2 0.2 V
Receiver Input Hysteresis VCM = 0V ● 60 mV
Receiver Output High Voltage IO = – 4mA, VID = 0.2V ● 3.5 V
Receiver Output Low Voltage IO = 4mA, VID = – 0.2V ● 0.4 V
Three-State Output Current at Receiver VCC = Max 0.4V ≤ VO ≤ 2.4V ● ±1 µA
Supply Current No Load; DI = GND or V

Receiver Input Resistance – 7V ≤ VCM ≤ 12V ● 12 kΩ
Driver Short-Circuit Current, V
Driver Short-Circuit Current, V
Receiver Short-Circuit Current 0V ≤ VO ≤ V

= High VO = – 7V ● 250 mA

OUT

= Low VO = 10 V ● 250 mA

OUT

ICSCD

R = 27Ω, (RS485) (Figure 1) ● 1.5 5 V

VCC = 0V or 5.25V, VIN = – 7V ● – 0.8 mA

Outputs Enabled ● 1.8 2.3 mA
Outputs Disabled ● 1.7 2.3 mA

CC

CC

● 785mA

2

LTC1485

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S

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VCC = 5V (Notes 2, 3), unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

t

PLH

t

PHL

t

SKEW

tr, t

f

t

ZH

t

ZL

t

LZ

t

HZ

t

PLH

t

PHL

t

SKEW

t

ZL

t

ZH

t

LZ

t

HZ

The ● denotes specifications which apply over the operating temperature
range.

Note 1: Absolute Maximum Ratings are those values beyond which the
safety of the device cannot be guaranteed.

I

TCH

GC CHARA TERIST

Driver Input to Output R

Driver Input to Output R

Driver Output to Output R

Driver Rise or Fall Time R

Driver Enable to Output High CL = 100pF (Figures 4, 6) S2 Closed ● 40 70 ns
Driver Enable to Output Low CL = 100pF (Figures 4, 6) S1 Closed ● 40 70 ns
Driver Disable Time from Low CL = 15pF (Figures 4, 6) S1 Closed ● 40 70 ns
Driver Disable Time from High CL = 15pF (Figures 4, 6) S2 Closed ● 40 70 ns
Receiver Input to Output R
Receiver Input to Output R
| t

– t

PLH

Differential Receiver Skew
Receiver Enable to Output Low CL = 15pF (Figures 3, 8) S1 Closed ● 30 45 ns
Receiver Enable to Output High CL = 15pF (Figures 3, 8) S2 Closed ● 30 45 ns
Receiver Disable from Low CL = 15pF (Figures 3, 8) S1 Closed ● 30 45 ns
Receiver Disable from High CL = 15pF (Figures 3, 8) S2 Closed ● 30 45 ns

|R

PHL

ICS

= 54Ω, CL1 = CL2 = 100pF ● 10 30 50 ns

DIFF

(Figures 2, 5)

= 54Ω, CL1 = CL2 = 100pF ● 10 30 50 ns

DIFF

(Figures 2, 5)

= 54Ω, CL1 = CL2 = 100pF ● 410 ns

DIFF

(Figures 2, 5)

= 54Ω, CL1 = CL2 = 100pF ● 51525 ns

DIFF

(Figures 2, 5)

= 54Ω, CL1 = CL2 = 100pF (Figures 2, 7) ● 15 25 50 ns

DIFF

= 54Ω, CL1 = CL2 = 100pF (Figures 2, 7) ● 20 30 55 ns

DIFF

= 54Ω, CL1 = CL2 = 100pF (Figures 2, 7) ● 515 ns

DIFF

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.

Note 3: All typicals are given for V

= 5V and TA = 25°C.

CC

LPER

F

O

Receiver Output Low Voltage vs
Output Current

36

TA = 25°C

32

28

24

20

16

12

OUTPUT CURRENT (mA)

8

4

0

0.5 1.5

0

1.0

OUTPUT VOLTAGE (V)

R

ATYPICA

2.0

1485 G01

UW

CCHARA TERIST

E

C

Receiver Output High Voltage vs
Output Current

–18

TA = 25°C

–16

–14

–12

–10

–8

–6

OUTPUT CURRENT (mA)

–4

–2

0

5

ICS

43

OUTPUT VOLTAGE (V)

1485 G02

2

Receiver Output High Voltage vs
Temperature

4.8
I = 8mA

4.6

4.4

4.2

4.0

3.8

3.6

OUTPUT VOLTAGE (V)

3.4

3.2

3.0

–25 125

–50

0

TEMPERATURE (°C)

50

25

75 100

1485 G03

3

LTC1485

TEMPERATURE (°C)

–50

1.55

INPUT THRESHOLD VOLTAGE (V)

1.59

50

1485 G09

1.57

–25 125

1.61

1.63

0

25

75 100

LPER

F

O

R

ATYPICA

UW

CCHARA TERIST

E

C

ICS

Receiver Output Low Voltage
vs Temperature

0.9
I = 8mA

0.8

0.7

0.6

0.5

0.4

0.3

OUTPUT VOLTAGE (V)

0.2

0.1

0

–25 125

–50

0

TEMPERATURE (°C)

50

25

Driver Output Low Voltage vs
Output Current

TA = 25°C

80

60

75 100

1485 G04

Driver Differential Output Voltage
vs Output Current

64

48

32

OUTPUT CURRENT (mA)

16

0

13

0

2

OUTPUT VOLTAGE (V)

Driver Output High Voltage vs
Output Current

–96

–72

TA = 25°C

TA = 25°C

4

1485 G05

Driver Differential Output Voltage
vs Temperature

2.4

2.2

2.0

1.8

DIFFERENTIAL VOLTAGE (V)

1.6
–50

0

–25 125

25

TEMPERATURE (°C)

50

TTL Input Threshold vs
Temperature

RL =54Ω

75 100

1485 G06

40

OUTPUT CURRENT (mA)

20

0

0

Receiver | t
Temperature

5

4

3

TIME (ns)

2

1

–50

–25 125

13

2

OUTPUT VOLTAGE (V)

– t

PLH

0

TEMPERATURE (°C)

| vs

PHL

25

50

4

1485 G07

75 100

1485 G10

–48

OUTPUT CURRENT (mA)

–24

0

5

4

3

TIME (ns)

2

1

–50

13

0

OUTPUT VOLTAGE (V)

0

–25 125

TEMPERATURE (°C)

2

4

1485 G08

Supply Current vs TemperatureDriver Skew vs Temperature

1.8

DRIVER ENABLED

1.7

1.6

DRIVER DISABLED

SUPPLY CURRENT (mA)

1.5

50

75 100

1485 G11

25

1.4
–50

0

–25 125

25

TEMPERATURE (°C)

50

75 100

1485 G12

4

LTC1485

1485 F04

C

L

S1

S2

500Ω

V

CC

OUTPUT

UNDER TEST

DI R

DIFF

1485 F02

DRIVER RECEIVER

C

L1

C

L2

RO

15pF

A

B

A

B

U

UU

PI FU CTIO S

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.

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.

TEST CIRCUITS

A

R

V

OD2

R

V

B

OC

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.

GND (Pin 5): Ground Connection.
A (Pin 6): Driver Output/Receiver Input.
B (Pin 7): Driver Output/Receiver Input.
V

(Pin 8): Positive Supply. 4.75V ≤ VCC ≤ 5.25V.

CC

1485 F01

Figure 1. Driver DC Test Load Figure 2. Driver/Receiver Timing Test Circuit

S1

RECEIVER

OUTPUT

C

1k

L

Figure 3. Receiver Timing Test Load

1k

V

CC

S2

1485 F03

Figure 4. Driver Timing Test Load

5

LTC1485

WITCHI

U
G

TI

V

A – VB

W

E

DI

–V

V

O

DE

A,B

W

WAVEFORS

3V

1.5V

0V

V

O

O

B

A

3V

0V

5V

V

OL

10%

t

50%

1/2 V

PLH

1.5V

t

ZL

t

r

O

2.3V

S

f = 1MHz; tr ≤ 10ns; tf ≤ 10ns

90%

1/2 V

O

t

SKEW

Figure 5. Driver Propagation Delays

f = 1MHz; tr ≤ 10ns; tf ≤ 10ns

t

OUTPUT NORMALLY LOW

1.5V

LZ

90%

1.5V

t

0.5V

PHL

t

f

t

SKEW

50%

10%

1485 F05

V

A,B

OH

0V

t

ZH

OUTPUT NORMALLY HIGH

2.3V

0.5V

t

HZ

1485 F06

Figure 6. Driver Enable and Disable Times

V

OD2

t

0V

PLH

– V

V

A

B

–V

OD2

V

OH

RO

V

OL

f = 1MHz; tr ≤ 10ns; tf ≤ 10ns

1.5V

INPUT

OUTPUT

0V

t

PHL

1.5V

1485 F07

Figure 7. Receiver Propagation Delays

6

LTC1485

WITCHI

U

G

TI

W

E

RO

RO

WAVEFORS

3V

RE

0V

5V

V

OL

V

OH

0V

1.5V

t

t

ZH

ZL

W
S

f = 1MHz; tr ≤ 10ns; tf ≤ 10ns

1.5V

OUTPUT NORMALLY LOW

1.5V

OUTPUT NORMALLY HIGH

Figure 8. Receiver Enable and Disable Times

PPLICATI

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Typical Application

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

1.5V

t

LZ

0.5V

0.5V

t

HZ

1485 F08

ends with a resistor equal to their characteristic imped­ance, typically 120Ω. The input impedance of a receiver is
typically 20k to GND, or 0.6 unit RS485 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.

RX

DX

1
2

3

4

LTC1485

RECEIVER

DRIVER

7

120Ω

8

RECEIVER

7

DRIVER

8

Figure 9. Typical Connection

120Ω

LTC1485

LTC1485

1

RECEIVER

DRIVER

1

RX

2

3

4

DX

2
3

4

1485 F09

RX

DX

7

LTC1485

FREQUENCY (MHz)

0.1

0.1

LOSS PER 100 FT (dB)

1

10

1 10 100

1485 F10

DATA RATE (bps)

10k

10

CABLE LENGTH (FT)

100

1k

10k

100k 1M 10M

1485 F11

2.5M

PPLICATI

A

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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 con­tention faults when two drivers are active on the bus at the
same time.

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.

Figure 10. Attenuation vs Frequency for Belden 9481

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 overall loss (Figure 10).

When using low loss cables, Figure 11 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 its 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

Figure 11. Cable Length vs Data Rate

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 12).

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
reflected back out of phase because of the mistermination.
When the reflected signal returns to the driver, the ampli­tude 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.

8

LTC1485

O

PPLICATI

A

DX

Rt = 120Ω

Rt = 47Ω

Rt = 470Ω

AC Cable Termination

S

PROBE HERE

DRIVER RECEIVER

Figure 12. Termination Effects

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I FOR ATIO

R

t

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RX

1485 F12

of the coupling capacitor should therefore be set at 16.3pF
per foot of cable length for 120Ω 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 400 feet
in length. Be aware that the power savings start to de­crease once the data rate surpasses 1/(120Ω • 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 LTC1485
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).

If the receiver output must be forced to a known state, the
circuits of Figure 14 can be used.

Cable termination resistors are necessary to prevent un­wanted 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.

120Ω

C

C = LINE LENGTH (FT) • 16.3pF

Figure 13. AC-Coupled Termination

RECEIVER

RX

1485 F13

The coupling capacitor must allow high frequency energy
to flow to the termination, but block DC and low frequen­cies. 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

5V

110Ω

130Ω

RECEIVER

110Ω

130Ω

5V

1.5k

120Ω

1.5k

5V

100k

C

120Ω

Figure 14. Forcing “0” When All Drivers Are Off

RECEIVER

RECEIVER

1485 F14

RX

RX

RX

9

LTC1485

PPLICATI

A

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S

I FOR ATIO

WU

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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.

Fault Protection

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
bidirectional TransZorb® from each line side pin to ground
(Figure 15).

A TransZorb is a silicon transient voltage suppressor that
has exceptional surge handling capabilities: fast response

A

DRIVER

Figure 15. ESD Protection with TransZorbs

120Ω

B

1485 F15

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 volt­age 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

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PPLICATITYPICAL

SA

RS232 Receiver

RS232

IN

5.6k

RS232 to RS485 Level Translator with Hysteresis

220k

RS232

IN

10k

DRIVER

5.6k

HYSTERESIS = 10k •  V

RECEIVER

1485 TA02

A

B

– VB /R ≈ 19 (kΩ • VOLT)/R

A

RX

120Ω

1485 TA03

10

PACKAGE DESCRIPTIO

U

Dimensions in inches (millimeters) unless otherwise noted.

N8 Package

8-Lead Plastic DIP

0.400*
(10.160)

MAX

876

LTC1485

5

0.255 ± 0.015*
(6.477 ± 0.381)

0.300 – 0.325

(7.620 – 8.255)

0.065

(1.651)

0.009 – 0.015

(0.229 – 0.381)

+0.025

0.325

–0.015

+0.635

8.255

()

–0.381

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm).

TYP

0.045 ± 0.015

(1.143 ± 0.381)

(2.540 ± 0.254)





12

0.045 – 0.065

(1.143 – 1.651)

0.100 ± 0.010

3

4

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.018 ± 0.003

(0.457 ± 0.076)

0.015

(0.380)



MIN

N8 0694

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 represen­tation that the interconnection of circuits as described herein will not infringe on existing patent rights.

11

LTC1485

PACKAGE DESCRIPTIO

U

Dimensions in inches (millimeters) unless otherwise noted.

S8 Package

8-Lead Plastic SOIC

0.189 – 0.197*
(4.801 – 5.004)

7

8

6

5

0.150 – 0.157*
(3.810 – 3.988)

4

0.004 – 0.010

(0.101 – 0.254)

0.050

(1.270)

BSC

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).

0.010 – 0.020

0.016 – 0.050

0.406 – 1.270

× 45°

0°– 8° TYP

0.228 – 0.244

(5.791 – 6.197)

0.053 – 0.069

(1.346 – 1.752)

0.014 – 0.019

(0.355 – 0.483)

1

3

2

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LTC486 Quad RS485 Driver Fits 75172 Pinout, Only 110µA I
LTC488 Quad RS485 Receiver Fits 75173 Pinout, Only 7mA I
LTC490 Full Duplex RS485 Transceiver Fits 75179 Pinout, Only 300µA I
LTC1481 Ultra-Low Power Half Duplex RS485 Transceiver Fits 75176 Pinout, 80µA I

Q

SO8 0294

Q

Q

Q

12

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7487

[phone]

●

FAX

: [phone]

●

TELEX

: 499-3977

LT/GP 0795 2K REV A • PRINTED IN THE USA

 LINEAR TECHNOLOGY CORPORATION 1995