LTC490

Features:

Low Power: ICC = 300mA Typical
Designed for RS485 or RS422 Applications
Single 5V Supply
7V to 12V Bus Common-Mode Range Permits ±7V Ground Difference Between Devices on the Bus
Thermal Shutdown Protection
Power-Up/Down Glitch-Free Driver Outputs Permit Live Insertion or Removal of Package
Driver Maintains High Impedance with the Power Off
Combined Impedance of a Driver Output and Receiver Allows up to 32 Transceivers on the Bus
70mV Typical Input Hysteresis
28ns Typical Driver Propagation Delays with 5ns Skew
 Pin Compatible with the SN75179


Application

Low Power RS485/RS422 Transceiver
 Level Translator


Specifications

Supply Voltage (VCC) ............................................... 12V
Driver Input Currents ........................... 25mA to 25mA
Driver Input Voltages ....................... 0.5V to VCC +0.5V
Driver Output Voltages .......................................... ±14V
Receiver Input Voltages ......................................... ±14V
Receiver Output Voltages ................ 0.5V to VCC +0.5V
Operating Temperature Range
LTC490C................................................. 0°C to 70°C
LTC490I.............................................  40°C to 85°C
Storage Temperature Range ................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C

Description

The LTC490 is a low power differential bus/line transceiver designed for multipoint data transmission standard RS485 applications with extended common-mode range (12V to
7V). It also meets the requirements of RS422. The CMOS design offers significant power savings over its
bipolar counterpart without sacrificing ruggedness against overload or ESD damage.

Excessive power dissipation of LTC490 caused by bus contention or faults is prevented by a thermal shutdown circuit which
forces the driver outputs into a high impedance state. The receiver has a fail safe feature which guarantees a high output state when the inputs are left open.

Both AC and DC specifications are guaranteed from 0°C to 70°C and 4.75V to 5.25V supply voltage range.