Datasheet LTC1688, LTC1689 Datasheet (Linear Technology)

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Page 1

FEATURES

■

Ultrahigh Speed:

■

Guaranteed Propagation Delay: 8ns ±4ns

100Mbps

Over Temperature

■

50Mbps Operation with VDD = 3V

■

Low Channel-to-Channel Skew: 500ps Typ

■

Low t

■

PLH/tPHL

Hot SwapTM Capable

Driver Outputs Maintain High Impedance in

Skew: 500ps Typ

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

APPLICATIO S

■

High Speed RS485 Twisted-Pair Drivers

■

High Speed Backplane Drivers

■

Complementary Clock Drivers

■

STS-1/OC-1 Data Drivers

■

SCSI Drivers

LTC1688/LTC1689

100Mbps RS485

Hot Swapable Quad Drivers

DESCRIPTIO

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, maintaining 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.

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

Hot Swap is a trademark of Linear Technology Corporation.

TYPICAL APPLICATIO

50Mbps RS485 Data Connection

DRIVER

100 FT CATEGORY 5 UTP

1/4 LTC1688

20ns Pulse Across 100 Feet

of Category 5 UTP

2V/DIV

100Ω100Ω

RECEIVER

1/4 LTC1518

1688/89 TA01

2V/DIV

5V/DIV

DRIVER INPUT

DRIVER OUTPUTS

CABLE DELAY

RECEIVER INPUT

RECEIVER OUTPUT

20ns/DIV

1688/89 TA02

Page 2

LTC1688/LTC1689

LUTEXI TIS

WUW

ARB

PACKAGE

RDER I FOR ATIO

(Note 1)

Supply Voltage (VDD)................................................ 7V

Enable Input Voltages................. –0.5V to (VDD + 0.5V)

Enable Input Currents..................... –100mA to 100mA

Driver Input Voltages.................. –0.5V to (VDD + 0.5V)

Driver Output Voltages ................. (–12V + VDD) to 12V

Driver Input Currents...................... –100mA to 100mA

Short-Circuit Duration (V

: –7V to 10V) ...... Indefinite

OUT

Operating Temperature Range.................... 0°C to 70°C

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

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

DC ELECTRICAL CHARACTERISTICS

DI1 DO1A DO1B

EN (EN12*)

DO2B DO2A

DI2

GND

Consult factory for Industrial and Military grade parts.

The ● denotes the specifications which apply over the full operating

TOP VIEW

1 2 3 4 5 6 7 8

S PACKAGE

16-LEAD PLASTIC SO

*LTC1689 ONLY

= 150°C, θ

JMAX

16 15 14 13 12 11 10

= 90°C/ W

DI4 DO4A DO4B ENB (EN34*) DO3B DO3A DI3

ORDER PART

NUMBER

LTC1688CS LTC1689CS

temperature range, otherwise specifications are at TA = 25°C.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VDD = 5V, Per Driver, TA = 25°C, Unless Otherwise Noted (Note 2)

OD1

OD2

∆V

∆VOC Change in Magnitude of Driver Common R = 25Ω or 50Ω, Figure 1 ● 0.2 V

IN1

OSD1

OSD2

VDD = 3V, Per Driver, TA = 25°C, Unless Otherwise Noted (Note 2)

OD1

OD2

∆V

Differential Driver Output (Unloaded) I Differential Driver Output (With Load) R = 50Ω (RS422) ● 2V

Change in Magnitude of Driver Differential R = 25Ω or 50Ω, Figure 1 ● 0.2 V Output Voltage for Complementary Output States

Driver Common Mode Output Voltage R = 25Ω or 50Ω, Figure 1 ● 23V

Mode Output Voltage for Complementary Output States

Input High Voltage EN, ENB, EN12, EN34, DI ● 2V Input Low Voltage EN, ENB, EN12, EN34, DI ● 0.8 V Input Current EN, ENB, EN12, EN34, DI ● ±1 µA Three-State (High Impedance) V

Output Current Supply Current of Entire Device No Load, Digital Input Pins = 0V or V Driver Short-Circuit Current, V Driver Short-Circuit Current, V

Differential Driver Output (Unloaded) I Differential Driver Output (With Load) R = 50Ω (RS422) 1.5 V

Change in Magnitude of Driver Differential R = 25Ω or 50Ω, Figure 1 0.1 V Output Voltage for Complementary Output States

Driver Common Mode Output Voltage R = 25Ω or 50Ω, Figure 1 1.3 V

= HIGH V

OUT

= LOW V

OUT

= 0 ● V

OUT

R = 25Ω (RS485), Figure 1

= –7V to 12V ● ±2 ±200 µA

OUT

= –7V to 10V ● ±20 mA

OUT

= –7V to 10V ● ±20 mA

OUT

= 0 ● V

OUT

R = 25Ω (RS485), Figure 1

● 1.5 3.0 V

● 918 mA

● 0.65 2.0 V

Page 3

LTC1688/LTC1689

DC ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

∆VOC Change in Magnitude of Driver Common R = 25Ω or 50Ω, Figure 1 0.1 V

Mode Output Voltage for Complementary

Output States V V I I

IL IN1 OZ

Input High Voltage EN, ENB, EN12, EN34, DI ● 1.4 V Input Low Voltage EN, ENB, EN12, EN34, DI ● 0.5 V Input Current EN, ENB, EN12, EN34, DI (Note 3) ● ±1 µA Three-State (High Impedance) V

= –7V to 10V (Note 3) ● ±1 ±200 µA

OUT

Output Current

OSD1

OSD2

Supply Current of Entire Device No Load, Digital Input Pins = 0V or V Driver Short-Circuit Current, V Driver Short-Circuit Current, V

= HIGH V

OUT

= LOW V

OUT

= –7V to 8V (Note 3) ● ±20 mA

OUT

= –7V to 8V (Note 3) ● ±20 mA

OUT

5mA

SWITCHING CHARACTERISTICS

temperature range, otherwise specifications are at TA = 25°C.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VDD = 5V, TA = 25°C, Unless Otherwise Noted (Note 2)

, t

PLH

SKEW

tr, t

L(MAX)

VDD = 3V, TA = 25°C, Unless Otherwise Noted (Note 2)

PLH

SKEW

tr, t

L(MAX)

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

Driver Input-to-Output Propagation Delay R

PHL

Figures 2, 4

Driver Output-to-Output Skew R

Figures 2, 4

Driver Rise/Fall Time R

Figures 2, 4 Driver Enable to Output High CL = 25pF, S2 Closed, Figures 3, 5 ● 10 35 ns Driver Enable to Output Low CL = 25pF, S1 Closed, Figures 3, 5 ● 10 35 ns Driver Disable from Low CL = 15pF, S1 Closed, Figures 3, 5 ● 25 65 ns Driver Disable from High CL = 15pF, S2 Closed, Figures 3, 5 ● 25 65 ns Maximum Output Capacitive Load (Note 3) ● 200 pF Maximum Data Rate (Note 3) ● 100 Mbps Maximum Driver Input Rise/Fall Time (Note 3) ● 500 ns

, t

Driver Input-to-Output Propagation Delay R

PHL

Figures 2, 4 Driver Output-to-Output Skew R

Figures 2, 4 Driver Rise/Fall Time R

Figures 2, 4 Driver Enable to Output High CL = 25pF, S2 Closed, Figures 3, 5 25 ns Driver Enable to Output Low CL = 25pF, S1 Closed, Figures 3, 5 25 ns Driver Disable from Low CL = 15pF, S1 Closed, Figures 3, 5 50 ns Driver Disable from High CL = 15pF, S2 Closed, Figures 3, 5 50 ns Maximum Output Capacitive Load (Note 3) ● 200 pF Maximum Data Rate 50 Mbps Maximum Driver Input Rise/Fall Time (Note 3) ● 500 ns

The ● denotes the specifications which apply over the full operating

= 50Ω, CL1 = CL2 = 25pF, ● 4812 ns

DIFF

= 50Ω, CL1 = CL2 = 25pF, 500 ps

DIFF

= 50Ω, CL1 = CL2 = 25pF, 2 ns

DIFF

= 50Ω, CL1 = CL2 = 25pF, 11 ns

DIFF

= 50Ω, CL1 = CL2 = 25pF, 1 ns

DIFF

= 50Ω, CL1 = CL2 = 25pF, 4 ns

DIFF

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.

Page 4

LTC1688/LTC1689

TYPICAL PERFORMANCE CHAR ACTERISTICS

Propagation Delay vs Temperature

PROPAGATION DELAY (ns)

VDI = 0V TO 3V

= 50Ω

DIFF

= 25pF

0 20 40 60 80 100

TEMPERATURE (°C)

VDD = 3V

VDD = 5V

Supply Current vs Data Rate

250

200

4 DRIVERS

150

VDD = 5V

= 50Ω, PER DRIVER

DIFF

= 25pF, PER DRIVER

100

SUPPLY CURRENT (mA)

= 25°C

0 20 40 60 80 100 120

DATA RATE (Mbps)

SWITCHING

1 DRIVER SWITCHING

1688/89 G01

1688/89 G03

Propagation Delay vs Load Capacitance

PROPAGATION DELAY (ns)

VDI = 0V TO 3V

= 50Ω

DIFF

= 25°C

0 10 20 30 40 50 60

LOAD CAPACITANCE (pF)

VDD = 3V

VDD = 5V

Three-State Output Current

4.0 VDD = 5V

3.5

3.0

= –7V

2.5

2.0

1.5

OUTPUT CURRENT (µA)

1.0

0.5

0 20 40 60 80 100

OUT

TEMPERATURE (°C)

OUT

1688/89 G02

= 12V

1688/89 G04

vs Temperature

OD2

2.5

2.0

1.5

OD2

1.0

0.5 R

= 50Ω

DIFF

0 20 40 60 80 100

TEMPERATURE (°C)

VDD = 5V

VDD = 3V

1688/89 G05

IDD vs TemperatureV

180 160 140 120 100

(mA)

80 60 40 20

4 DRIVERS LOADED

1 DRIVER LOADED

VDD = 5V

= 50Ω, PER DRIVER

DIFF

0.1Mbps

0 20 40 60 80 100

TEMPERATURE (°C)

1688/89 G06

Page 5

UUU

1688/89 TC03

OUTPUT

UNDER TEST

500

Ω

PIN FUNCTIONS

LTC1688/LTC1689

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

bypassed with a 0.1µF ceramic capacitor as close to the pin as possible. Recommended: VDD = 3V to 5.25V.

FU CTIO TA B LES

LTC1688

INPUTS OUTPUTS

DI EN ENB OUTA OUTB

HH X H L LHX L H HX L H L LX L L H X L H HI-Z HI-Z

TEST CIRCUITS

1688/89 TC01

Figure 1. Driver DC Test Load

EN (EN12)

DRIVER

ENB (EN34)

Figure 2. Driver Timing Test Circuit

LTC1689

DIFF

INPUTS OUTPUTS

DI EN12/EN34 OUTA OUTB

HHHL LHLH X L HI-Z HI-Z

1688/89 TC02

Figure 3. Driver Timing Test Load

Page 6

LTC1688/LTC1689

UW W

SWITCHI G TI E WAVEFOR S

–V

1/2 V

1.5V

PLH

10% t

SKEW

90%

Figure 4. Driver Propagation Delays

A, B

1.5V 1.5V t

1/2 V

Figure 5. Driver Enable and Disable Times

WUU

APPLICATIONS INFORMATION

f = 1MHz; tr < 3ns; tf < 3ns

= V(A) – V(B)

DIFF

f = 1MHz; t

≤ 3ns; tf ≤ 3ns

OUTPUT NORMALLY LOW

OUTPUT NORMALLY HIGH

1/2 V

1.5V

PHL

SKEW

90%

10%

0.5V

1688/89 F04

1688/89 F05

The LTC1688/LTC1689 family of RS485 quad differential drivers employs a novel architecture and fabrication process 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-

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.

LTC1689 OUTPUT

2V/DIV

FAR END OF CABLE

2V/DIV

RECEIVER OUTPUT

5V/DIV

20ns/DIV

1688/89 F06

Figure 6. 3V High Speed Data Transmission

Page 7

LTC1688/LTC1689

WUU

APPLICATIONS INFORMATION

Hot Swap Capability

With the LTC1688/LTC1689 outputs disabled but connected to the transmission line, the user can turn on/off the power to the LTC1688/LTC1689 without inducing a differential signal on the transmission line. Due to capacitive coupling, however, there can be a small amount of common 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 transmission 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 shortcircuit 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

VDD/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 shortcircuit 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.

A OUTPUT

B OUTPUT

Figure 7. Common Mode Charge Injection During Hot Swapping

Page 8

LTC1688/LTC1689

WUU

APPLICATIONS INFORMA TION

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 impedance should be chosen close to 100Ω 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.

Enable Pins

For cable terminations with a DC bias (such as High Voltage Differential SCSI, see Figure 10), the driver outputs 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.

1/4 LTC1688

1/4 LTC1519

100Ω 100Ω

Figure 8. Multipoint Transmission Figure 9. Point-to-Point Transmission

1/4 LTC1688

1/4 LTC1518

TERM POWER

330Ω

150Ω

330Ω

1688/89 F08

TERM POWER

1/4 LTC1518

1/4 LTC1689

330Ω

150Ω

330Ω

1/4 LTC1518

1688/89 F10

100Ω

1/4 LTC1518

1688/89 F09

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

Page 9

LTC1688/LTC1689

WUU

APPLICATIONS INFORMATION

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.

2V/DIV

DRIVER INPUT

High Speed Backplane Transmission

The LTC1688/LTC1689 can be used in backplane point-topoint 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 100Ω; therefore, PC trace transmission lines should be designed with an impedance close to 100Ω. If trace impedance is much less than 100Ω, 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 UltraFastTM comparator is a good choice for high data rate backplane applications.

2V/DIV

5V/DIV

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

DRIVER OUTPUT

RECEIVER INPUT

RECEIVER OUTPUT

10ns/DIV

1688/89 F11

1/4 LTC1688

DRIVER

Figure 13. 100Mbps Backplane Transmission

TRANSMISSION LINE

BACKPLANE

DRIVER

25 FT CATEGORY 5 UTP

1/4 LTC1688

Figure 12. 100Mbps Differential Data Connection

1/2 LT1720

100Ω

RECEIVER

1688/89 F13

100Ω100Ω

RECEIVER

–

1688/89 F12

UltraFast is a trademark of Linear Technology Corporation.

Page 10

LTC1688/LTC1689

WUU

APPLICATIONS INFORMA TION

Layout Considerations

A ground plane is recommended when using high frequency devices like the LTC1688/LTC1689. A 0.1µF ceramic bypass capacitor less than 0.25 inch away from the VDD 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 capacitance 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 fastest 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 provided 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.

DRIVER

1/4 LTC1688 1/4 LTC1689

CATEGORY 5 CABLE

UNDER TEST

100Ω100Ω

Figure 14. Test Circuit for Cable Speed Evaluation

CABLE DELAY

2V/DIV

2µs/DIV

RECEIVER

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

1688/89 F16

1688/89 F14

CABLE DELAY

2V/DIV

2µs/DIV

Figure 15. 4000 Feet, 0.5Mbps, LTC1518 Receiver

CABLE DELAY

2V/DIV

500ns/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

1688/89 F15

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

1688/89 F17

Figure 17. 1000 Feet, 2Mbps, LTC1518 ReceiverFigure 16. 4000 Feet, 1Mbps, LTC1518 Receiver

Page 11

LTC1688/LTC1689

WUU

APPLICATIONS INFORMATION

DRIVER INPUT

CABLE DELAY

2V/DIV

500ns/DIV

RECEIVER INPUT

RECEIVER OUTPUT

1688/89 F18

2V/DIV

CABLE DELAY

Figure 19. 1000 Feet, 1Mbps, LTC1518 ReceiverFigure 18. 1000 Feet, 5Mbps, LTC1518 Receiver

1µs/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

1688/89 F19

2V/DIV

CABLE DELAY

100ns/DIV

DRIVER INPUT

RECEIVER INPUT

RECEIVER OUTPUT

1688/89 F20

DRIVER INPUT

RECEIVER INPUT

2V/DIV

DRIVER INPUT

CABLE DELAY

50ns/DIV

RECEIVER INPUT

RECEIVER OUTPUT

1688/89 F21

Figure 21. 200 Feet, 33Mbps, LTC1518 ReceiverFigure 20. 200 Feet, 20Mbps, LTC1518 Receiver

DRIVER INPUT

CABLE DELAY

RECEIVER INPUT

RECEIVER OUTPUT

50ns/DIV

1688/89 F22

Figure 23. 25 Feet, 100Mbps, BRF2A ReceiverFigure 22. 100 Feet, 50Mbps, LTC1518 Receiver

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

10ns/DIV

RECEIVER OUTPUT

1688/89 F23

Page 12

LTC1688/LTC1689

PACKAGE DESCRIPTION

Dimensions in inches (millimeters) unless otherwise noted.

S Package

16-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.386 – 0.394*

(9.804 – 10.008)

0.010 – 0.020

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

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

0.016 – 0.050

(0.406 – 1.270)

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)

TYP

0.150 – 0.157** (3.810 – 3.988)

0.050

(1.270)

BSC

0.004 – 0.010

(0.101 – 0.254)

S16 1098

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LTC486/LTC487 Low Power Quad RS485 Drivers 110µA Typ Supply Current, 10Mbps, –7V to 12V Common Mode Range LT®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

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

 LINEAR TECHNOLOGY CORPORATION 1999

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507

●

www.linear-tech.com