LT1785/LT1785A/ LT1791/LT1791A 60V Fault Protected RS485/RS422 Transceivers Fea T Descrip T 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 The LT1785A/LT1791A devices have fail-safe receiver inputs to guarantee a receiver output high for shorted, open a T or inactive data lines. On-chip ESD protection eliminates n need for external protection devices. Industrial Control Data Networks n CAN Bus Applications The LT1785/LT1785A are available in 8-lead DIP and SO n HVAC Controls packages and the LT1791/LT1791A in 14-lead DIP and L, LT, LTC, LTM, Module, Linear Technology and the Linear logo are registered trademarks of SO packages. Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical a T Normal Operation Waveforms at 250kBaud V CC1 RO1 RX RO RE1 LT1785 R TERM DE1 DI1 TX Y-Z GND1 DI V CC2 RO2 RX RE2 R LT1785 TERM 178591 TA02 DE2 DI2 TX GND2 178591 TA01 178591fd 1 For more information www.linear.com/LT1785 ion pplica ions pplica ion uresLT1785/LT1785A/ LT1791/LT1791A (Note 1) a Te Maxi Mu M r a T 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 p in c F T 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 Der in F Ma T 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 178591fd 2 For more information www.linear.com/LT1785 ion or or ion igura on ings bsolu