LTC1686/LTC1687 52Mbps Precision Delay RS485 Fail-Safe Transceivers DESCRIPTION FEATURES n Precision Propagation Delay Over Temperature: The LTC 1686/LTC1687 are high speed, precision delay, Receiver/Driver: 18.5ns 3.5ns full-duplex RS485 transceivers that can operate at data n High Data Rate: 52Mbps rates as high as 52Mbps. The devices also meet the n Low t /t Skew: requirements of RS422. PLH PHL Receiver/Driver: 500ps Typ A unique architecture provides very stable propagation n 7V to 12V RS485 Input Common Mode Range delays and low skew over a wide common mode and n Guaranteed Fail-Safe Operation Over the Entire ambient temperature range. Common Mode Range n The driver and receiver feature three-state outputs, with High Input Resistance: 22k, Even When Unpowered n disabled driver outputs maintaining high impedance over Short-Circuit Protected n the entire common mode range. A short-circuit feature Thermal Shutdown Protected n detects shorted outputs and substantially reduces driver Driver Maintains High Impedance in Three-State or output current. A similar feature also protects the receiver with Power Off n output from short circuits. Thermal shutdown circuitry Single 5V Supply n protects from excessive power dissipation. Pin Compatible with LTC490/LTC491 n 45dB CMRR at 26MHz The receiver has a fail-safe feature that guarantees a high output state when the inputs are shorted or are left floating. U APPLICATIONS The LTC1686/LTC1687 RS485 transceivers guarantee receiver fail-safe operation over the entire common mode n High Speed RS485/RS422 Full Duplex Transceivers range (7V to 12V). Receiver input resistance remains n Level Translator 22k when the device is unpowered or disabled. n Backplane Transceiver n The LTC1686/LTC1687 operate from a single 5V supply STS-1/OC-1 Data Transceiver n and draw only 7mA of supply current. Signal Repeaters , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION 10Mbps Data Pulse 400 Feet Category 5 UTP LTC1686 LTC1686 DRIVER INPUT 2V/DIV 5 CABLE DELAY 3 100W 100W D DRIVER RECEIVER R 6 RECEIVER 1V/DIV INPUT 8 2 100W 100W R RECEIVER DRIVER D 7 RECEIVER 5V/DIV OUTPUT 400 FT OF CATEGORY 5 UTP 100ns/DIV 1686/87 TA02 LTC1686/87 TA01 1 U ULTC1686/LTC1687 O ABS LUTEXAI U RATI GS (Note 1) Supply Voltage (V ) .............................................. 10V Driver Short-Circuit Duration DD Control Input Currents .................... 100mA to 100mA (V : 7V to 10V) ..................................... Indefinite OUT Control Input Voltages .................. 0.5V to V + 0.5V Receiver Short-Circuit Duration DD Driver Input Voltages .................... 0.5V to V + 0.5V (V : 0V to V ) ........................................ Indefinite OUT DD DD Driver Output Voltages ................................. +12V/7V Operating Temperature Range Receiver Input Voltages ................................ +12V/7V LTC1686C/LTC1687C ............................. 0 C to 70 C Receiver Output Voltages ............. 0.5V to V + 0.5V LTC1686I/LTC1687I .......................... 40 C to 85 C DD Receiver Input Differential ...................................... 10V Storage Temperature Range ................ 65 C to 150 C Lead Temperature (Soldering, 10 sec)................. 300 C PACKAGE/ORDER I FOR ATIO TOP VIEW ORDER PART ORDER PART NC 1 14 V DD TOP VIEW NUMBER NUMBER 2 R 13 NC R V 1 8 A DD R RE 3 12 A LTC1686CS8 LTC1687CS R 2 7 B DE 4 11 B D 3 6 Z LTC1686IS8 LTC1687IS D D 5 10 Z GND 4 5 Y D GND 6 9 Y S8 PART MARKING S8 PACKAGE GND 7 8 NC 8-LEAD PLASTIC SO S PACKAGE T = 125 C, q = 150 C/ W JMAX JA 1686 14-LEAD PLASTIC SO 1686I T = 125 C, q = 90 C/ W JMAX JA Consult factory for Industrial and Military grade parts. DC ELECTRICAL CHARACTERISTICS V = 5V 5% unless otherwise noted (Notes 2, 3). DD SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Differential Driver Output (Unloaded) I = 0 l V V OD1 OUT DD V Differential Driver Output (With Load) R = 50W (RS422) 2.0 V OD2 R = 27W (RS485), Figure 1 l 1.5 V V DD D V Change in Magnitude of Driver Differential R = 27W or 50W , Figure 1 l 0.2 V OD Output Voltage for Complementary Output States V Driver Common Mode Output Voltage R = 27W or 50W , V = 5V, Figure 1 l23 V OC DD D V Change in Magnitude of Driver Common R = 27W or 50W , Figure 1 l 0.2 V OC Mode Output Voltage for Complementary Output States V Input High Voltage D, DE, RE l2V IH V Input Low Voltage D, DE, RE l 0.8 V IL I Input Current D, DE, RE l 1 1 m A IN1 I Input Current (A, B) V , V = 12V, V = 0V or 5.25V l 500 m A IN2 A B DD V , V = 7V, V = 0V or 5.25V l 500 m A A B DD V Differential Input Threshold Voltage 7V V 12V l 0.3 0.3 V TH CM for Receiver D V Receiver Input Hysteresis V = 0V 25 mV TH CM V Receiver Output High Voltage I = 4mA, V = 300mV l 3.5 4.8 V OH OUT ID 2 U WU U W W W