LTC1688/LTC1689 100Mbps RS485 Hot Swapable Quad Drivers U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Ultrahigh Speed: 100Mbps Guaranteed Propagation Delay: 8ns ±4ns Over Temperature 50Mbps Operation with VDD = 3V Low Channel-to-Channel Skew: 500ps Typ Low tPLH/tPHL Skew: 500ps Typ Hot SwapTM 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 U APPLICATIO S ■ ■ ■ ■ 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. High Speed RS485 Twisted-Pair Drivers High Speed Backplane Drivers Complementary Clock Drivers STS-1/OC-1 Data Drivers SCSI Drivers 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. U ■ 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. TYPICAL APPLICATIO 20ns Pulse Across 100 Feet of Category 5 UTP 50Mbps RS485 Data Connection DRIVER 100Ω 100Ω DRIVER INPUT 2V/DIV DRIVER OUTPUTS RECEIVER CABLE DELAY 100 FT CATEGORY 5 UTP 1/4 LTC1688 2V/DIV 2V/DIV RECEIVER INPUT 5V/DIV RECEIVER OUTPUT 1/4 LTC1518 1688/89 TA01 20ns/DIV 1688/89 TA02 1 LTC1688/LTC1689 U U RATI GS W W W W AXI U U ABSOLUTE PACKAGE/ORDER 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 (VOUT: – 7V to 10V) ...... Indefinite Operating Temperature Range .................... 0°C to 70°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C ORDER PART NUMBER TOP VIEW DI1 1 16 VDD DO1A 2 15 DI4 DO1B 3 14 DO4A EN (EN12*) 4 13 DO4B DO2B 5 12 ENB (EN34*) DO2A 6 11 DO3B DI2 7 10 DO3A 9 GND 8 LTC1688CS LTC1689CS DI3 S PACKAGE 16-LEAD PLASTIC SO *LTC1689 ONLY TJMAX = 150°C, θJA = 90°C/ W Consult factory for Industrial and Military grade parts. 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 VDD V 3.0 V V 0.2 V 3 V 0.2 V VDD = 5V, Per Driver, TA = 25°C, Unless Otherwise Noted (Note 2) VOD1 Differential Driver Output (Unloaded) IOUT = 0 ● VOD2 Differential Driver Output (With Load) R = 50Ω (RS422) R = 25Ω (RS485), Figure 1 ● ● 2 1.5 ∆VOD Change in Magnitude of Driver Differential Output Voltage for Complementary Output States R = 25Ω or 50Ω, Figure 1 ● VOC Driver Common Mode Output Voltage R = 25Ω or 50Ω, Figure 1 ● ∆VOC Change in Magnitude of Driver Common Mode Output Voltage for Complementary Output States R = 25Ω or 50Ω, Figure 1 ● VIH Input High Voltage EN, ENB, EN12, EN34, DI ● VIL Input Low Voltage EN, ENB, EN12, EN34, DI ● 0.8 V IIN1 Input Current EN, ENB, EN12, EN34, DI ● ±1 µA IOZ Three-State (High Impedance) Output Current VOUT = – 7V to 12V ● ±2 ±200 µA IDD Supply Current of Entire Device No Load, Digital Input Pins = 0V or VDD ● 9 18 mA IOSD1 Driver Short-Circuit Current, VOUT = HIGH VOUT = – 7V to 10V ● ± 20 mA IOSD2 Driver Short-Circuit Current, VOUT = LOW VOUT = – 7V to 10V ● ± 20 mA VDD V 2.0 V V 2 2 V VDD = 3V, Per Driver, TA = 25°C, Unless Otherwise Noted (Note 2) VOD1 Differential Driver Output (Unloaded) IOUT = 0 ● VOD2 Differential Driver Output (With Load) R = 50Ω (RS422) R = 25Ω (RS485), Figure 1 ● 1.5 0.65 ∆VOD Change in Magnitude of Driver Differential Output Voltage for Complementary Output States R = 25Ω or 50Ω, Figure 1 0.1 V VOC Driver Common Mode Output Voltage R = 25Ω or 50Ω, Figure 1 1.3 V 2 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 ∆VOC Change in Magnitude of Driver Common Mode Output Voltage for Complementary Output States R = 25Ω or 50Ω, Figure 1 VIH Input High Voltage EN, ENB, EN12, EN34, DI ● VIL Input Low Voltage EN, ENB, EN12, EN34, DI ● IIN1 Input Current EN, ENB, EN12, EN34, DI (Note 3) ● IOZ Three-State (High Impedance) Output Current VOUT = – 7V to 10V (Note 3) ● IDD Supply Current of Entire Device No Load, Digital Input Pins = 0V or VDD IOSD1 Driver Short-Circuit Current, VOUT = HIGH VOUT = – 7V to 8V (Note 3) ● ±20 mA IOSD2 Driver Short-Circuit Current, VOUT = LOW VOUT = – 7V to 8V (Note 3) ● ±20 mA 0.1 UNITS V 1.4 V 0.5 ±1 ±1 µA ±200 µA 5 U SWITCHING CHARACTERISTICS V mA 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 4 8 12 UNITS VDD = 5V, TA = 25°C, Unless Otherwise Noted (Note 2) tPLH, tPHL Driver Input-to-Output Propagation Delay RDIFF = 50Ω, CL1 = CL2 = 25pF, Figures 2, 4 tSKEW Driver Output-to-Output Skew RDIFF = 50Ω, CL1 = CL2 = 25pF, Figures 2, 4 500 ps tr, tf Driver Rise/Fall Time RDIFF = 50Ω, CL1 = CL2 = 25pF, Figures 2, 4 2 ns tZH Driver Enable to Output High CL = 25pF, S2 Closed, Figures 3, 5 ● 10 35 ns tZL Driver Enable to Output Low CL = 25pF, S1 Closed, Figures 3, 5 ● 10 35 ns tLZ Driver Disable from Low CL = 15pF, S1 Closed, Figures 3, 5 ● 25 65 ns t HZ Driver Disable from High CL = 15pF, S2 Closed, Figures 3, 5 ● 25 CL(MAX) Maximum Output Capacitive Load (Note 3) ● Maximum Data Rate (Note 3) ● Maximum Driver Input Rise/Fall Time (Note 3) ● ● ns 65 ns 200 pF 100 Mbps 500 ns VDD = 3V, TA = 25°C, Unless Otherwise Noted (Note 2) tPLH, tPHL Driver Input-to-Output Propagation Delay RDIFF = 50Ω, CL1 = CL2 = 25pF, Figures 2, 4 11 ns tSKEW Driver Output-to-Output Skew RDIFF = 50Ω, CL1 = CL2 = 25pF, Figures 2, 4 1 ns tr, tf Driver Rise/Fall Time RDIFF = 50Ω, CL1 = CL2 = 25pF, Figures 2, 4 4 ns tZH Driver Enable to Output High CL = 25pF, S2 Closed, Figures 3, 5 25 ns tZL Driver Enable to Output Low CL = 25pF, S1 Closed, Figures 3, 5 25 ns tLZ Driver Disable from Low CL = 15pF, S1 Closed, Figures 3, 5 50 ns t HZ Driver Disable from High CL = 15pF, S2 Closed, Figures 3, 5 50 ns CL(MAX) Maximum Output Capacitive Load (Note 3) Maximum Driver Input Rise/Fall Time 200 ● Maximum Data Rate 50 (Note 3) Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. ● pF Mbps 500 ns 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. 3 LTC1688/LTC1689 U W TYPICAL PERFORMANCE CHARACTERISTICS Propagation Delay vs Temperature Propagation Delay vs Load Capacitance 14 14 VDD = 3V 10 8 VDD = 5V 6 4 VDI = 0V TO 3V RDIFF = 50Ω CL = 25pF 2 VDD = 3V 12 PROPAGATION DELAY (ns) PROPAGATION DELAY (ns) 12 10 VDD = 5V 8 6 4 VDI = 0V TO 3V RDIFF = 50Ω TA = 25°C 2 0 0 0 20 40 60 80 TEMPERATURE (°C) 0 100 10 20 30 40 50 LOAD CAPACITANCE (pF) 60 1688/89 G02 1688/89 G01 Three-State Output Current Supply Current vs Data Rate 250 4.0 3.5 VDD = 5V OUTPUT CURRENT (µA) SUPPLY CURRENT (mA) 200 4 DRIVERS SWITCHING 150 VDD = 5V RDIFF = 50Ω, PER DRIVER CL = 25pF, PER DRIVER TA = 25°C 100 1 DRIVER SWITCHING 50 3.0 VOUT = –7V 2.5 2.0 1.5 1.0 0.5 0 VOUT = 12V 0 0 20 40 60 80 DATA RATE (Mbps) 100 120 0 20 40 60 80 TEMPERATURE (°C) 1688/89 G03 100 1688/89 G04 VOD2 vs Temperature IDD vs Temperature 2.5 180 4 DRIVERS LOADED 160 VDD = 5V 2.0 140 120 VOD2 IDD (mA) 1.5 VDD = 3V 1.0 100 1 DRIVER LOADED 80 60 40 0.5 20 RDIFF = 50Ω 0 0 0 20 40 60 80 TEMPERATURE (°C) 100 1688/89 G05 4 VDD = 5V RDIFF = 50Ω, PER DRIVER 0.1Mbps 0 20 40 60 80 TEMPERATURE (°C) 100 1688/89 G06 LTC1688/LTC1689 U U U PIN FUNCTIONS DI1 (Pin 1): Driver 1 Input. Do not float. DI3 (Pin 9): Driver 3 Input. Do not float. DO1A (Pin 2): Driver 1 Noninverting Output. DO3A (Pin 10): Driver 3 Noninverting Output. DO1B (Pin 3): Driver 1 Inverting Output. DO3B (Pin 11): Driver 3 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. 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. 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. 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. DO2B (Pin 5): Driver 2 Inverting Output. DO4B (Pin 13): Driver 4 Inverting Output. DO2A (Pin 6): Driver 2 Noninverting Output. DO4A (Pin 14): Driver 4 Noninverting Output. DI2 (Pin 7): Driver 2 Input. Do not float. DI4 (Pin 15): Driver 4 Input. Do not float. GND (Pin 8): Ground Connection. A good ground plane is recommended for all applications. 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. U U FU CTIO TABLES LTC1688 LTC1689 INPUTS OUTPUTS INPUTS OUTPUTS DI EN ENB OUTA OUTB DI EN12/EN34 OUTA OUTB H H X H L H H H L L H X L H L H L H H X L H L X L HI-Z HI-Z L X L L H X L H HI-Z HI-Z TEST CIRCUITS EN (EN12) A S1 CL1 R VDD A VOD R VOC DI DRIVER B OUTPUT UNDER TEST RDIFF CL B CL2 1688/89 TC01 S2 1688/89 TC02 ENB (EN34) Figure 1. Driver DC Test Load 500Ω Figure 2. Driver Timing Test Circuit 1688/89 TC03 Figure 3. Driver Timing Test Load 5 LTC1688/LTC1689 U W W SWITCHI G TI E WAVEFOR S 3V DI f = 1MHz; tr < 3ns; tf < 3ns 1.5V 1.5V 0V tPLH tPHL B VO A tSKEW 1/2 VO VO 1/2 VO 90% tSKEW 90% 10% VDIFF = V(A) – V(B) 10% – VO tr 1688/89 F04 tf Figure 4. Driver Propagation Delays 3V EN f = 1MHz; tr ≤ 3ns; tf ≤ 3ns 1.5V 1.5V 0V tZL 5V A, B VOL VOH A, B tLZ 1/2 VDD OUTPUT NORMALLY LOW 1/2 VDD OUTPUT NORMALLY HIGH 0.5V 0.5V 0V tZH 1688/89 F05 tHZ Figure 5. Driver Enable and Disable Times U W U U APPLICATIONS INFORMATION 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- 6 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 LTC1688/LTC1689 U U W U 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 7 LTC1688/LTC1689 U U W U APPLICATIONS INFORMATION Cable Termination Enable Pins 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. 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 LTC1519 1/4 LTC1688 100Ω 100Ω 1/4 LTC1518 100Ω 1/4 LTC1689 1/4 LTC1518 1688/89 F08 1688/89 F09 Figure 8. Multipoint Transmission DE DI Figure 9. Point-to-Point Transmission TERM POWER TERM POWER 330Ω 330Ω 150Ω 150Ω 1/4 LTC1688 330Ω 1/4 LTC1518 1/4 LTC1518 330Ω 1688/89 F10 Figure 10. DC-Biased Termination (Recommended for SCSI Applications Only) 8 LTC1688/LTC1689 U W U U APPLICATIONS INFORMATION High Speed Twisted-Pair Transmission High Speed Backplane 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. 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 2V/DIV 2V/DIV 5V/DIV DRIVER INPUT DRIVER OUTPUT RECEIVER INPUT RECEIVER OUTPUT DRIVER 100Ω 100Ω + RECEIVER – 25 FT CATEGORY 5 UTP 10ns/DIV 1/4 LTC1688 1688/89 F11 1688/89 F12 Figure 12. 100Mbps Differential Data Connection Figure 11. 8ns Pulse Over 25 Feet Category 5 UTP 1/4 LTC1688 1/2 LT1720 BACKPLANE DRIVER TRANSMISSION LINE 100Ω RECEIVER 1688/89 F13 Figure 13. 100Mbps Backplane Transmission UltraFast is a trademark of Linear Technology Corporation. 9 LTC1688/LTC1689 U W U U APPLICATIONS INFORMATION 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 INPUT CABLE DELAY RECEIVER INPUT 2V/DIV DRIVER 100Ω 100Ω RECEIVER OUTPUT RECEIVER CATEGORY 5 CABLE UNDER TEST 1/4 LTC1688 1/4 LTC1689 2µs/DIV 1688/89 F14 1688/89 F15 Figure 14. Test Circuit for Cable Speed Evaluation Figure 15. 4000 Feet, 0.5Mbps, LTC1518 Receiver DRIVER INPUT DRIVER INPUT CABLE DELAY RECEIVER INPUT CABLE DELAY RECEIVER INPUT 2V/DIV 2V/DIV RECEIVER OUTPUT 2µs/DIV Figure 16. 4000 Feet, 1Mbps, LTC1518 Receiver 10 1688/89 F16 RECEIVER OUTPUT 500ns/DIV Figure 17. 1000 Feet, 2Mbps, LTC1518 Receiver 1688/89 F17 LTC1688/LTC1689 U W U U APPLICATIONS INFORMATION DRIVER INPUT DRIVER INPUT CABLE DELAY CABLE DELAY RECEIVER INPUT 2V/DIV RECEIVER INPUT 2V/DIV RECEIVER OUTPUT 500ns/DIV RECEIVER OUTPUT 1µs/DIV 1688/89 F18 Figure 18. 1000 Feet, 5Mbps, LTC1518 Receiver 1688/89 F19 Figure 19. 1000 Feet, 1Mbps, LTC1518 Receiver DRIVER INPUT DRIVER INPUT CABLE DELAY CABLE DELAY RECEIVER INPUT RECEIVER INPUT 2V/DIV 2V/DIV RECEIVER OUTPUT 100ns/DIV RECEIVER OUTPUT 50ns/DIV 1688/89 F20 Figure 20. 200 Feet, 20Mbps, LTC1518 Receiver 1688/89 F21 Figure 21. 200 Feet, 33Mbps, LTC1518 Receiver DRIVER INPUT DRIVER INPUT CABLE DELAY CABLE DELAY RECEIVER INPUT RECEIVER INPUT 2V/DIV 2V/DIV RECEIVER OUTPUT 50ns/DIV Figure 22. 100 Feet, 50Mbps, LTC1518 Receiver 1688/89 F22 RECEIVER OUTPUT 10ns/DIV 1688/89 F23 Figure 23. 25 Feet, 100Mbps, BRF2A 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. 11 LTC1688/LTC1689 U 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) 16 15 14 13 12 11 10 9 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 2 3 4 5 6 7 8 0.053 – 0.069 (1.346 – 1.752) 0.004 – 0.010 (0.101 – 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 S16 1098 *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 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 12 Linear Technology Corporation 16889f LT/TP 1099 4K • PRINTED IN THE USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1999