LT1785/LT1785A/ LT1791/LT1791A 60V Fault Protected RS485/RS422 Transceivers FEATURES DESCRIPTION n Protected from Overvoltage Line Faults to 60V The LT 1785/LT1791 are half-duplex and full-duplex differ- n Pin Compatible with LTC485 and LTC491 ential bus transceivers for RS485 and RS422 applications n High Input Impedance Supports Up to 128 Nodes which feature on-chip protection from overvoltage faults n No Damage or Latchup to ESD on the data transmission lines. Receiver input and driver n IEC-1000-4-2 Level 4: 15kV Air Discharge output pins can withstand voltage faults up to 60V with n IEC-1000-4-2 Level 2: 4kV Contact Discharge respect to ground with no damage to the device. Faults n Controlled Slew Rates for EMI Emissions Control may occur while the transceiver is active, shut down or n Guaranteed High Receiver Output State for Floating, powered off. Shorted or Inactive Inputs (LT1785A/LT1791A) Data rates to 250kbaud on networks of up to 128 nodes n Outputs Assume a High Impedance When Off or are supported. Controlled slew rates on the driver out- Powered Down putscontrol EMI emissions and improve data transmis- n Drives Low Cost, Low Impedance Cables sion integrity on improperly terminated lines. Drivers are n Short-Circuit Protection on All Outputs specified to operate with inexpensive cables as low as n Thermal Shutdown Protection 72 characteristic impedance. n Guaranteed Operation to 125C n The LT1785A/LT1791A devices have fail-safe receiver AEC-Q100 Qualified for Automotive Applications inputs to guarantee a receiver output high for shorted, open (LT1785 W) or inactive data lines. On-chip ESD protection eliminates need for external protection devices. APPLICATIONS The LT1785/LT1785A are available in 8-lead DIP and SO n Industrial Control Data Networks packages and the LT1791/LT1791A in 14-lead DIP and n CAN Bus Applications SO packages. n HVAC Controls All registered trademarks and trademarks are the property of their respective owners. TYPICAL APPLICATION Normal Operation Waveforms at 250kBaud V CC1 RO1 RX RE1 RO LT1785 R TERM DE1 DI1 TX Y-Z GND1 V CC2 DI RO2 RX RE2 R LT1785 TERM 178591 TA02 DE2 DI2 TX GND2 178591 TA01 Rev. F 1 Document Feedback For more information www.analog.comLT1785/LT1785A/ LT1791/LT1791A (Note 1) ABSOLUTE MAXIMUM RATINGS Supply Voltage (V ) ................................................18V Operating Temperature Range CC Receiver Enable Input Voltage ...................... 0.3V to 6V LT1785C/LT1791C/ Driver Enable Input Voltage .......................... 0.3V to 6V LT1785AC/LT1791AC .................................... 0C to 70C Driver Input Voltage ................................... 0.3V to 18V LT1785I/LT1791I/ Receiver Input Voltage ................................ 60V to 60V LT1785AI/LT1791AI .................................. 40C to 85C Driver Output Voltage .................................. 60V to 60V LT1785H/LT1791H/ Receiver Output Voltage ...................0.3V to (V + 6V) LT1785AH/LT1791AH ............................. 40C to 125C CC Storage Temperature Range ................... 65C to 150C Lead Temperature (Soldering, 10 sec) .................. 300C PIN CONFIGURATION TOP VIEW TOP VIEW 14 NC 1 V CC RO 2 R 13 NC RO 1 V 8 CC R RE 3 12 A RE 2 7 B DE 4 11 B DE 3 6 A D DI 5 10 Z DI 4 5 GND D GND 6 9 Y N8 PACKAGE S8 PACKAGE GND 7 8 NC 8-LEAD PDIP 8-LEAD PLASTIC SO T = 150C, = 130C/W (N8) JMAX JA N PACKAGE S PACKAGE T = 150C, = 150C/W (S8) JMAX JA 14-LEAD PDIP 14-LEAD PLASTIC SO T = 150C, = 130C/W (N) JMAX JA T = 150C, = 150C/W (S) JMAX JA ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT1785CN8 PBF LT1785CN8 TRPBF 1785 8-Lead PDIP 0C to 70C LT1785CS8 PBF LT1785CS8 TRPBF 1785 8-Lead Plastic SO 0C to 70C LT1785IN8 PBF LT1785IN8 TRPBF 1785I 8-Lead PDIP 40C to 85C LT1785IS8 PBF LT1785IS8 TRPBF 1785I 8-Lead Plastic SO 40C to 85C LT1785ACN8 PBF LT1785ACN8 TRPBF 1785A 8-Lead PDIP 0C to 70C LT1785ACS8 PBF LT1785ACS8 TRPBF 1785A 8-Lead Plastic SO 0C to 70C LT1785AIN8 PBF LT1785AIN8 TRPBF 1785AI 8-Lead PDIP 40C to 85C LT1785AIS8 PBF LT1785AIS8 TRPBF 1785AI 8-Lead Plastic SO 40C to 85C LT1785HN8 PBF LT1785HN8 TRPBF 1785H 8-Lead PDIP 40C to 125C LT1785HS8 PBF LT1785HS8 TRPBF 1785H 8-Lead Plastic SO 40C to 125C LT1785AHN8 PBF LT1785AHN8 TRPBF 1785AH 8-Lead PDIP 40C to 125C LT1785AHS8 PBF LT1785AHS8 TRPBF 1785AH 8-Lead Plastic SO 40C to 125C LT1791CN PBF LT1791CN TRPBF 1791 14-Lead PDIP 0C to 70C LT1791CS PBF LT1791CS TRPBF 1791 14-Lead Plastic SO 0C to 70C Rev. F 2 For more information www.analog.com