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LTC1482 - Low Power RS485 Transceiver with Carrier Detect and Receiver Fail-Safe

The LTC®1482 is a low power RS485 compatible transceiver that offers an active low carrier detect output. The open-drain carrier detect pin allows several transceivers to share the same carrier detect line and can be used to detect the insertion or removal of a driven RS485/RS422 cable. Enhanced ESD protection allows the LTC1482 to withstand ±15kV (human body model), IEC-1000-4-2 level 4 (±8kV) contact and level 3 (±8kV) air discharge ESD without latchup or damage. The LTC1482 receiver stays alive at all times except in shutdown. The supply current is a maximum of 700µA and 900µA when the driver is disabled and enabled respectively. In shutdown, the quiescent current of the LTC1482 drops to a maximum of 20µA. When the driver is disabled or the LTC1482 is in shutdown, the driver outputs are three-stated and remain in a high impedance state over the RS485 common mode range. Excessive power dissipation caused by bus contention or faults is prevented by a thermal shutdown circuit, which forces the driver outputs into a high impedance state. The LTC1482 is fully specified over the commercial and industrial temperature ranges and is available in 8-lead MSOP, PDIP and SO packages.

Features No Damage or Latchup to ±15kV (Human BodyModel), IEC1000-4-2 Level 4 (±8kV) Contact andLevel 3 (±8kV) Active Low Carrier Detect Output Guaranteed High Receiver Output State forFloating, Shorted or Terminated Inputs withNo Signal Present Drives Low Cost Residential Telephone Wires Low Power: ICC = 700µA Max with Driver Disabled ICC = 900µA Max in Driver Mode Without Load 20µA Max Quiescent Current in Shutdown Mode Single 5V Supply –7V to 12V Common Mode Range Permits ±7VGround Difference Between Devices on the Data Line Maximum Data Rate of 4Mbps Power Up/Down Glitch-Free Driver Outputs Up to 32 Transceivers on the Bus Available in 8-Lead MSOP, PDIP and SO Packages Typical Application

Applications Battery-Powered RS485/RS422 Applications Low Power RS485/RS422 Transceiver Level Translator Packaging