LTC1535 Isolated RS485 Transceiver Fea T Descrip T n UL Rated Isolated RS485: 2500V The LTC 1535 is an isolated RS485 full-duplex differential RMS UL Recognized File E151738 line transceiver. Isolated RS485 is ideal for systems where n Eliminates Ground Loops the ground loop is broken to allow for much larger com- n 250kBd Maximum Data Rate mon mode voltage ranges. An internal capacitive isola- n Self-Powered with 420kHz Converter tion barrier provides 2500V of isolation between the RMS n Half- or Full-Duplex line transceiver and the logic level interface. The powered n Fail-Safe Output High for Open or side contains a 420kHz push-pull converter to power the Shorted Receiver Inputs isolated RS485 transceiver. Internal full-duplex commu- n Short-Circuit Current Limit nication occurs through the capacitive isolation barrier. n Slow Slew Rate Control The transceiver meets RS485 and RS422 requirements. n 68k Input Impedance Allows Up to 128 Nodes The driver and receiver feature three-state outputs, with n Thermal Shutdown the driver maintaining high impedance over the entire n 8kV ESD Protection On Driver Outputs and common mode range. The drivers have short-circuit cur- Receiver Inputs rent limits in both directions and a slow slew rate select n Available in 28-Lead SW Package to minimize EMI or reflections. The 68k receiver input allows up to 128 node connections. A fail-safe feature a T defaults to a high output state when the receiver inputs n Isolated RS485 Receiver/Driver are open or shorted. n RS485 with Large Common Mode Voltage L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Analog Devices, Inc. All other trademarks are the property of their respective owners. n Breaking RS485 Ground Loops n Multiple Unterminated Line Taps Typical a T ** CTX02-14659 1/2 BAT54C + 10F 2 1/2 BAT54C 2 2 3 11 14 ST1 ST2 GND2 V CC2 V 1 V CC CC 420kHz + 10F A 1 16 RO TWISTED-PAIR RO 28 R LOGIC COMMON CABLE B 15 1 FLOATING RS485 COMMON RO2 17 RE 2 RE 27 ** EATON (888) 414-2645 Y DE 13 26 DE D DI Z DI 25 12 4 GND SLO 18 1 1535 TA01 1535fc 1 For more information www.linear.com/LTC1535 ion pplica ions pplica ion uresLTC1535 a Te Maxi Mu M r a T p in c F T (Note 1) V to GND .................................................................6V TOP VIEW CC V to GND2 ..............................................................8V V 1 CC2 28 RO CC Control Input Voltage to GND ....... 0.3V to (V + 0.3V) ST1 2 27 RE CC ST2 3 Driver Input Voltage to GND ..........0.3V to (V + 0.3V) 26 DE CC GND 4 25 DI Driver Output Voltage (Driver Disabled) to GND2 ...............(V 13V) to 13V CC2 Driver Output Voltage (Driver Enabled) to GND2 ................ (V 13V) to 10V CC2 Receiver Input Voltage to GND2 .............................. 14V Receiver Output Voltage ...............0.3V to (V + 0.3V) CC Operating Temperature Range GND2 11 18 SLO LTC1535C ..........................................0C T 70C A Z 12 17 RO2 LTC1535I ...................................... 40C T 85C A Y 13 16 A Storage Temperature Range ..................65C to 150C V 14 15 B CC2 Lead Temperature (Soldering, 10 sec) ...................300C SW PACKAGE 28-LEAD PLASTIC SO T = 125C, = 125C/W JMAX JA o r Der i n F Ma T