LTC1688/LTC1689

100Mbps RS485

Hot Swapable Quad Drivers

Ultrahigh Speed:

100Mbps

Guaranteed Propagation Delay: 8ns

4ns

Over Temperature

50Mbps Operation with V

= 3V

Low Channel-to-Channel Skew: 500ps Typ

Low t

PLH

PHL

Skew: 500ps Typ

Hot Swap

Capable

Driver Outputs Maintain High Impedance in
Three-State or with Power Off

Short-Circuit Protected: 3mA Typ Output Current
for an Indefinite Short

Thermal Shutdown Protected

Single 5V or 3V Supply

Pin Compatible with LTC486/LTC487

The LTC

1688/LTC1689 are ultrahigh speed, differential

bus/line drivers that can operate at data rates up to
100Mbps. Propagation delay is guaranteed at 8ns

4ns

over the full operating temperature range. These devices
operate over the full RS485 common mode range ( 7V
to 12V), and also meet RS422 requirements.

The driver outputs are Hot Swap capable, maintaining
backplane data integrity during board insertion and
removal. The drivers feature three-state outputs, maintain-
ing high impedance over the entire common mode range
( 7V to 12V). Outputs also remain high impedance during
power-up and with the power off. A short-circuit feature
detects bus contention and substantially reduces driver
output current. Thermal shutdown circuitry protects the
parts from excessive power dissipation.

The LTC1688 allows all four drivers to be enabled together,
while the LTC1689 allows two drivers at a time to be
enabled.

The LTC1688/LTC1689 operate from a single 5V or 3V
supply and draw only 9mA of supply current.

High Speed RS485 Twisted-Pair Drivers

High Speed Backplane Drivers

Complementary Clock Drivers

STS-1/OC-1 Data Drivers

SCSI Drivers

Hot Swap is a trademark of Linear Technology Corporation.

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

20ns Pulse Across 100 Feet

of Category 5 UTP

20ns/DIV

2V/DIV

5V/DIV

1688/89 TA02

DRIVER INPUT

DRIVER OUTPUTS

RECEIVER INPUT

RECEIVER OUTPUT

CABLE DELAY

1688/89 TA01

RECEIVER

1/4 LTC1688

100

1/4 LTC1518

100 FT CATEGORY 5 UTP

DRIVER

50Mbps RS485 Data Connection

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

LTC1688/LTC1689

PACKAGE/ORDER I FOR ATIO

BSOLUTE

(Note 1)

Supply Voltage (V

) ................................................ 7V

Enable Input Voltages ................. 0.5V to (V

+ 0.5V)

Enable Input Currents ..................... 100mA to 100mA
Driver Input Voltages .................. 0.5V to (V

+ 0.5V)

Driver Output Voltages ................. ( 12V + V

) to 12V

Driver Input Currents ...................... 100mA to 100mA
Short-Circuit Duration (V

OUT

: 7V to 10V) ...... Indefinite

Operating Temperature Range .................... 0

C to 70

Storage Temperature Range ................ 65

C to 150

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

DC ELECTRICAL CHARACTERISTICS

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

= 5V, Per Driver, T

= 25

C, Unless Otherwise Noted (Note 2)

OD1

Differential Driver Output (Unloaded)

OUT

= 0

OD2

Differential Driver Output (With Load)

R = 50

(RS422)

R = 25

(RS485), Figure 1

1.5

3.0

Change in Magnitude of Driver Differential

R = 25

or 50

, Figure 1

0.2

Output Voltage for Complementary
Output States

Driver Common Mode Output Voltage

R = 25

or 50

, Figure 1

Change in Magnitude of Driver Common

R = 25

or 50

, Figure 1

0.2

Mode Output Voltage for Complementary
Output States

Input High Voltage

EN, ENB, EN12, EN34, DI

Input Low Voltage

EN, ENB, EN12, EN34, DI

0.8

IN1

Input Current

EN, ENB, EN12, EN34, DI

Three-State (High Impedance)

OUT

= 7V to 12V

200

Output Current

Supply Current of Entire Device

No Load, Digital Input Pins = 0V or V

OSD1

Driver Short-Circuit Current, V

OUT

= HIGH

OUT

= 7V to 10V

OSD2

Driver Short-Circuit Current, V

OUT

= LOW

OUT

= 7V to 10V

= 3V, Per Driver, T

= 25

C, Unless Otherwise Noted (Note 2)

OD1

Differential Driver Output (Unloaded)

OUT

= 0

OD2

Differential Driver Output (With Load)

R = 50

(RS422)

1.5

R = 25

(RS485), Figure 1

0.65

2.0

Change in Magnitude of Driver Differential

R = 25

or 50

, Figure 1

0.1

Output Voltage for Complementary
Output States

Driver Common Mode Output Voltage

R = 25

or 50

, Figure 1

1.3

ORDER PART

NUMBER

LTC1688CS
LTC1689CS

TOP VIEW

S PACKAGE

16-LEAD PLASTIC SO

*LTC1689 ONLY

DI1

DO1A

DO1B

EN (EN12*)

DO2B

DO2A

DI2

GND

DI4

DO4A

DO4B

ENB (EN34*)

DO3B

DO3A

DI3

JMAX

= 150

= 90

C/ W

Consult factory for Industrial and Military grade parts.

The

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

= 25

LTC1688/LTC1689

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Change in Magnitude of Driver Common

R = 25

or 50

, Figure 1

0.1

Mode Output Voltage for Complementary
Output States

Input High Voltage

EN, ENB, EN12, EN34, DI

1.4

Input Low Voltage

EN, ENB, EN12, EN34, DI

0.5

IN1

Input Current

EN, ENB, EN12, EN34, DI (Note 3)

Three-State (High Impedance)

OUT

= 7V to 10V (Note 3)

200

Output Current

Supply Current of Entire Device

No Load, Digital Input Pins = 0V or V

OSD1

Driver Short-Circuit Current, V

OUT

= HIGH

OUT

= 7V to 8V (Note 3)

OSD2

Driver Short-Circuit Current, V

OUT

= LOW

OUT

= 7V to 8V (Note 3)

Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.

Note 2: All currents into the device pins are positive; all currents out of the
device pins are negative.

Note 3: Guaranteed by design or correlation, but not tested.

SWITCHI

G CHARACTERISTICS

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

= 5V, T

= 25

C, Unless Otherwise Noted (Note 2)

PLH

, t

PHL

Driver Input-to-Output Propagation Delay

DIFF

= 50

, C

= C

= 25pF,

Figures 2, 4

SKEW

Driver Output-to-Output Skew

DIFF

= 50

, C

= C

= 25pF,

500

Figures 2, 4

, t

Driver Rise/Fall Time

DIFF

= 50

, C

= C

= 25pF,

Figures 2, 4

Driver Enable to Output High

= 25pF, S2 Closed, Figures 3, 5

Driver Enable to Output Low

= 25pF, S1 Closed, Figures 3, 5

Driver Disable from Low

= 15pF, S1 Closed, Figures 3, 5

Driver Disable from High

= 15pF, S2 Closed, Figures 3, 5

L(MAX)

Maximum Output Capacitive Load

(Note 3)

200

Maximum Data Rate

(Note 3)

100

Mbps

Maximum Driver Input Rise/Fall Time

(Note 3)

500

= 3V, T

= 25

C, Unless Otherwise Noted (Note 2)

PLH

, t

PHL

Driver Input-to-Output Propagation Delay

DIFF

= 50

, C

= C

= 25pF,

Figures 2, 4

SKEW

Driver Output-to-Output Skew

DIFF

= 50

, C

= C

= 25pF,

Figures 2, 4

, t

Driver Rise/Fall Time

DIFF

= 50

, C

= C

= 25pF,

Figures 2, 4

Driver Enable to Output High

= 25pF, S2 Closed, Figures 3, 5

Driver Enable to Output Low

= 25pF, S1 Closed, Figures 3, 5

Driver Disable from Low

= 15pF, S1 Closed, Figures 3, 5

Driver Disable from High

= 15pF, S2 Closed, Figures 3, 5

L(MAX)

Maximum Output Capacitive Load

(Note 3)

200

Maximum Data Rate

Mbps

Maximum Driver Input Rise/Fall Time

(Note 3)

500

DC ELECTRICAL CHARACTERISTICS

The

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

= 25

The

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

= 25

LTC1688/LTC1689

TYPICAL PERFOR

CE CHARACTERISTICS

Propagation Delay
vs Temperature

TEMPERATURE (

PROPAGATION DELAY (ns)

1688/89 G01

100

= 0V TO 3V

DIFF

= 50

= 25pF

= 3V

= 5V

Supply Current vs Data Rate

DATA RATE (Mbps)

250

200

150

100

SUPPLY CURRENT (mA)

1688/89 G03

100

120

= 5V

DIFF

= 50

, PER DRIVER

= 25pF, PER DRIVER

= 25

4 DRIVERS
SWITCHING

1 DRIVER
SWITCHING

LOAD CAPACITANCE (pF)

PROPAGATION DELAY (ns)

1688/89 G02

= 0V TO 3V

DIFF

= 50

= 25

= 3V

= 5V

Propagation Delay
vs Load Capacitance

TEMPERATURE (

OUTPUT CURRENT (

1688/89 G04

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

100

= 5V

OUT

= 12V

OUT

= 7V

TEMPERATURE (

2.5

2.0

1.5

1.0

0.5

OD2

1688/89 G05

100

DIFF

= 50

= 5V

= 3V

TEMPERATURE (

180

160

140

120

100

(mA)

1688/89 G06

100

= 5V

DIFF

= 50

, PER DRIVER

0.1Mbps

1 DRIVER LOADED

4 DRIVERS LOADED

Three-State Output Current

vs Temperature

OD2

vs Temperature

LTC1688/LTC1689

CTIO

DI1 (Pin 1): Driver 1 Input. Do not float.

DO1A (Pin 2): Driver 1 Noninverting Output.

DO1B (Pin 3): Driver 1 Inverting Output.

EN (Pin 4, LTC1688): High True Enable Pin, enables all
four drivers. A low on Pin 4 and a high on Pin 12 will put
all driver outputs into a high impedance state. See
Function Tables for details. Do not float.

EN12 (Pin 4, LTC1689): Enables Drivers 1 and 2. A low on
Pin 4 will put the outputs of drivers 1 and 2 into a high
impedance state. See Function Tables for details. Do not
float.

DO2B (Pin 5): Driver 2 Inverting Output.

DO2A (Pin 6): Driver 2 Noninverting Output.

DI2 (Pin 7): Driver 2 Input. Do not float.

GND (Pin 8): Ground Connection. A good ground plane is
recommended for all applications.

DI3 (Pin 9): Driver 3 Input. Do not float.

DO3A (Pin 10): Driver 3 Noninverting Output.

DO3B (Pin 11): Driver 3 Inverting Output.

ENB (Pin 12, LTC1688): Low True Enable Pin, enables all
four drivers. A low on Pin 4 and a high on Pin 12 will put
all driver outputs into a high impedance state. See
Function Tables for details. Do not float.

EN34 (Pin 12, LTC1689): Enables Drivers 3 and 4. A low
on Pin 12 will put the outputs of drivers 3 and 4 into a high
impedance state. See Function Tables for details. Do not
float.

DO4B (Pin 13): Driver 4 Inverting Output.

DO4A (Pin 14): Driver 4 Noninverting Output.

DI4 (Pin 15): Driver 4 Input. Do not float.

(Pin 16): Power Supply Input. This pin should be

bypassed with a 0.1

F ceramic capacitor as close to the

pin as possible. Recommended: V

= 3V to 5.25V.

FU CTIO TABLES

LTC1688

INPUTS

OUTPUTS

ENB

OUTA

OUTB

HI-Z

LTC1689

INPUTS

OUTPUTS

EN12/EN34

OUTA

OUTB

HI-Z

1688/89 TC03

OUTPUT

UNDER TEST

500

1688/89 TC01

Figure 1. Driver DC Test Load

Figure 3. Driver Timing Test Load

DRIVER

1688/89 TC02

ENB (EN34)

EN (EN12)

DIFF

Figure 2. Driver Timing Test Circuit

TEST CIRCUITS

LTC1688/LTC1689

APPLICATIO

S I

FOR

ATIO

The LTC1688/LTC1689 family of RS485 quad differential
drivers employs a novel architecture and fabrication pro-
cess that allows ultra high speed operation (100Mbps)
and Hot Swap capability while maintaining the ruggedness
of RS485 operation (three-state outputs can float from
7V to 12V with a single 5V supply). Unlike typical CMOS
drivers whose propagation delay can vary as much as
500%, the propagation delay of the LTC1688/LTC1689
drivers will only vary by

50% (a narrow

4ns window).

This performance is achieved by designing the input stage
of each driver to have minimum propagation delay shift
over temperature and from part to part.

The LTC1688/LTC1689 have an ESD rating of 6kV human
body model.

50Mbps with 3V Operation

The LTC1688/LTC1689 are designed to operate with a 3V
power supply and still achieve 50Mbps operation (see
Electrical Characteristics table for 3V DC and AC specifica-

1688/89 F04

1/2 V

SKEW

1.5V

PLH

1.5V

PHL

1/2 V

DIFF

= V(A) V(B)

90%

10%

90%

10%

SKEW

f = 1MHz; t

3ns; t

< 3ns

Figure 4. Driver Propagation Delays

1688/89 F05

A, B

f = 1MHz; t

3ns; t

3ns

1.5V

OUTPUT NORMALLY LOW

1/2 V

0.5V

A, B

OUTPUT NORMALLY HIGH

0.5V

Figure 5. Driver Enable and Disable Times

SWITCHI G TI E WAVEFOR S

Figure 6. 3V High Speed Data Transmission

20ns/DIV

2V/DIV

5V/DIV

1688/89 F06

LTC1689 OUTPUT

RECEIVER OUTPUT

FAR END OF CABLE

tions). Figure 6 shows waveforms of an LTC1689 driving
a receiver using 100 feet of Category 5 UTP. Both parts are
operating at 3V supply.

LTC1688/LTC1689

APPLICATIO

S I

FOR

ATIO

Hot Swap Capability

With the LTC1688/LTC1689 outputs disabled but con-
nected to the transmission line, the user can turn on/off the
power to the LTC1688/LTC1689 without inducing a differ-
ential signal on the transmission line. Due to capacitive
coupling, however, there can be a small amount of com-
mon mode charge injected into both disabled outputs,
which is not seen as a differential signal (see Figure 7). The
disabled outputs can be hooked/unhooked to a transmis-
sion line without disturbing the existing data.

Output Short-Circuit Protection

In addition to 100Mbps operation and Hot Swap capability,
the LTC1688/LTC1689 employ voltage sensing short-
circuit protection that reduces short-circuit current by
over an order of magnitude. For a given input polarity, this
circuitry determines what the correct output level should
be. If the output level is different from the expected, the
circuitry shuts off the big output devices. Much smaller
devices are instead turned on, thus producing a much
smaller short-circuit output current (3mA typical). For
example, if the driver input is > 2V, it expects the "A" output
to be > 3.25V and the "B" output to be less than 1.75V. If
the "A" output is subsequently shorted to a voltage below

/2, this circuitry shuts off the big outputs and turns on

3mA current sources instead (the converse applies to the
"B" output). Note that these 3mA current sources are
active only during a short-circuit fault. During normal
operation, the regular output drivers can sink/source
> 50mA.

A time-out period of about 50ns is required before a short-
circuit fault is detected. This circuitry might falsely detect
a short under excess output capacitive load (> 200pF).
Additionally, a short might go undetected if there is too
much resistance (user inserted or cable parasitic) between
the physical short and the actual driver output.

For cables with the recommended RS485 termination (no
DC bias on the cable, see Figure 8), the LTC1688/LTC1689
will automatically come out of short-circuit mode once the
physical short has been removed.

To prevent permanent damage to the part, the maximum
allowable short is 10V (not 12V). Note that during a short,
the voltage right at the pin should not ring to a voltage
higher than 12V. Instability could surface if the short is
made with long leads (parasitic inductance). Once the
short is removed, the instability will disappear.

Figure 7. Common Mode Charge Injection During Hot Swapping

A OUTPUT

B OUTPUT

LTC1688/LTC1689

Cable Termination

The recommended cable termination for use with the
LTC1688/LTC1689 is a single resistor across the two ends
of a transmission cable (see Figure 8). When PC traces are
used as the transmission line, its characteristic imped-
ance should be chosen close to 100

in order to better

match the specified timing characteristics of the LTC1688/
LTC1689. Category 5 unshielded twisted pair can be used
over short distances at the maximum data rates (100Mbps).
For point-to-point configurations (see Figure 9), a single
resistor across the cable at the receiver end is sufficient.
A single resistor termination lowers power consumption
and increases the differential output signal. See Enable
Pins section for cable terminations with a DC bias.

APPLICATIO

S I

FOR

ATIO

Enable Pins

For cable terminations with a DC bias (such as High
Voltage Differential SCSI, see Figure 10), the driver out-
puts must be disabled for at least 200ns after power-up.
This ensures that the driver outputs do not disturb the
cable upon power-up. It also ensures the correct output
start-up conditions. When there is an output short fault
condition and the cable has a DC biased termination, such
as Figure 10, the driver outputs must be disabled for at
least 200ns after the short has been removed. Recall that
for transmission lines that have the recommended RS485
single resistor termination (Figures 8 and 9), the LTC1688/
LTC1689 will come out of a short-circuit fault condition
automatically without having to disable the outputs.

1688/89 F10

1/4 LTC1518

150

330

1/4 LTC1688

TERM POWER

150

330

TERM POWER

1/4 LTC1518

Figure 10. DC-Biased Termination
(Recommended for SCSI Applications Only)

Figure 8. Multipoint Transmission

Figure 9. Point-to-Point Transmission

1688/89 F08

1/4 LTC1518

1/4 LTC1519

100

1/4 LTC1688

1688/89 F09

1/4 LTC1518

100

1/4 LTC1689

LTC1688/LTC1689

APPLICATIO

S I

FOR

ATIO

High Speed Twisted-Pair Transmission

Data rates up to 100Mbps can be transmitted over short
distances using Category 5 UTP (unshielded twisted pair).
The cable distance will determine the maximum data rate.
Figures 11 and 12 show an 8ns pulse propagating over 25
feet of Category 5 UTP. Notice how the cable attenuates the
signal. Lucent Technologies' BRF2A and BRS2A receivers
are recommended for these ultrahigh speed applications.

High Speed Backplane Transmission

The LTC1688/LTC1689 can be used in backplane point-to-
point and multipoint applications. At high data rates,
signals should be routed differentially and PC traces
should be terminated (see Figure 13). Note that the RS485
specification calls for characteristic impedances near 100

;

therefore, PC trace transmission lines should be designed
with an impedance close to 100

. If trace impedance is

much less than 100

, and the trace is double terminated,

the part will experience excess heating. The propagation
delay could then fall outside the specified window. The
LT1720 dual UltraFast

comparator is a good choice for

high data rate backplane applications.

Figure 12. 100Mbps Differential Data Connection

Figure 11. 8ns Pulse Over 25 Feet Category 5 UTP

10ns/DIV

2V/DIV

5V/DIV

1688/89 F11

DRIVER INPUT

DRIVER OUTPUT

RECEIVER INPUT

RECEIVER OUTPUT

1688/89 F12

RECEIVER

1/4 LTC1688

100

25 FT CATEGORY 5 UTP

DRIVER

Figure 13. 100Mbps Backplane Transmission

BACKPLANE

RECEIVER

1/4 LTC1688

1/2 LT1720

100

1688/89 F13

DRIVER

TRANSMISSION LINE

UltraFast is a trademark of Linear Technology Corporation.

LTC1688/LTC1689

APPLICATIO

S I

FOR

ATIO

Layout Considerations

A ground plane is recommended when using high fre-
quency devices like the LTC1688/LTC1689. A 0.1

ceramic bypass capacitor less than 0.25 inch away from
the V

pin is also recommended. Special care should be

taken to route the differential outputs very symmetrically
in order to obtain the same parasitic capacitances and thus
maintain good propagation delay skew.

Parasitic capacitance from each input to its corresponding
outputs should also be minimized. Any excess capaci-
tance could result in slower operation or even instability.
Channel output pairs should be kept away from other
output pairs to avoid parasitic coupling.

Data Rate vs Cable Length

Cable length and quality limit the maximum data rate in a
twisted pair system. Category 5 unshielded twisted pair is
a good choice for high speed data transmission, as it
exhibits superior bandwidth over other cables of similar
cost.

Driver and receiver bandwidth affects the maximum data
rate only over distances of less than 100', even for the best
cables. The LTC1688/LTC1689 RS485 drivers and
LTC1518/LTC1519 52Mbps RS485 receivers are the fast-
est in the industry. The LTC1688/LTC1689 drivers can
reach speeds over 100Mbps, with a rise and fall time of
just 2ns. At speeds in excess of 52Mbps, the non-RS485
Lucent Technologies' BRF2A receiver is recommended.

Detailed information on data rate vs cable length is pro-
vided by the cable manufacturer. They characterize their
cables for bit rate and 0% to 50% rise time vs cable length,
allowing a rapid comparison of various cable types.

The following oscilloscope waveforms illustrate how a
cable attenuates the signal and slows its rise time at
different lengths. Also shown are the driver input and
receiver output.

1688/89 F14

RECEIVER

1/4 LTC1688
1/4 LTC1689

100

CATEGORY 5 CABLE

UNDER TEST

DRIVER

Figure 14. Test Circuit for Cable Speed Evaluation

s/DIV

1688/89 F15

2V/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

CABLE DELAY

Figure 15. 4000 Feet, 0.5Mbps, LTC1518 Receiver

s/DIV

1688/89 F16

2V/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

CABLE DELAY

Figure 17. 1000 Feet, 2Mbps, LTC1518 Receiver

Figure 16. 4000 Feet, 1Mbps, LTC1518 Receiver

500ns/DIV

1688/89 F17

2V/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

CABLE DELAY

LTC1688/LTC1689

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 its circuits as described herein will not infringe on existing patent rights.

Figure 19. 1000 Feet, 1Mbps, LTC1518 Receiver

Figure 18. 1000 Feet, 5Mbps, LTC1518 Receiver

APPLICATIO

S I

FOR

ATIO

Figure 21. 200 Feet, 33Mbps, LTC1518 Receiver

Figure 20. 200 Feet, 20Mbps, LTC1518 Receiver

Figure 23. 25 Feet, 100Mbps, BRF2A Receiver

Figure 22. 100 Feet, 50Mbps, LTC1518 Receiver

500ns/DIV

1688/89 F18

2V/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

CABLE DELAY

s/DIV

1688/89 F19

2V/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

CABLE DELAY

100ns/DIV

1688/89 F20

2V/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

CABLE DELAY

50ns/DIV

1688/89 F21

2V/DIV

DRIVER INPUT

RECEIVER
OUTPUT

CABLE DELAY

RECEIVER INPUT

50ns/DIV

1688/89 F22

2V/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

CABLE DELAY

10ns/DIV

1688/89 F23

2V/DIV

DRIVER INPUT

RECEIVER
OUTPUT

CABLE DELAY

RECEIVER INPUT

LTC1688/LTC1689

LINEAR TECHNOLOGY CORPORATION 1999

16889f LT/TP 1099 4K ˇ PRINTED IN THE USA

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900

FAX: (408) 434-0507

www.linear-tech.com

PART NUMBER

DESCRIPTION

COMMENTS

LTC486/LTC487

Low Power Quad RS485 Drivers

110

A Typ Supply Current, 10Mbps, 7V to 12V Common Mode Range

1394

7ns UltraFast Single Supply Comparator

6mA Typ Supply Current, Ground Sensing on Single Supply

LTC1518/LTC1519

High Speed, Precision Quad RS485 Receivers

52Mbps, Pin Compatible with LTC488/LTC489

LTC1520

High Speed, Precision Quad Differential Line Receiver

Single Supply, 18ns Propagation Delay, 100mV Threshold

LTC1685

High Speed, Precision RS485 Transceiver

52Mbps, Pin Compatible with LTC485

LTC1686/LTC1687

High Speed, Precision RS485 Full-Duplex Transceivers

52Mbps, Pin Compatible with LTC490/LTC491

LT1720

Dual 4.5ns UltraFast Single Supply Comparator

4mA per Comparator, Optimized for 3V or 5V Operation

RELATED PARTS

PACKAGE DESCRIPTIO

Dimensions in inches (millimeters) unless otherwise noted.

S Package

16-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.016 0.050

(0.406 1.270)

0.010 0.020

(0.254 0.508)

TYP

0.008 0.010

(0.203 0.254)

0.150 0.157**

(3.810 3.988)

0.386 0.394*

(9.804 10.008)

0.228 0.244

(5.791 6.197)

S16 1098

0.053 0.069

(1.346 1.752)

0.014 0.019

(0.355 0.483)

TYP

0.004 0.010

(0.101 0.254)

0.050

(1.270)

BSC

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

Part Number LTC1688