LTC491 - Differential Driver and Receiver Pair

The LTC®491 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.

The driver and receiver feature three-state outputs, with the driver outputs maintaining high impedance over the entire 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 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.

  • Low Power: ICC = 300µA 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 in Three-State or 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 for 2.5MB Operation
  • Pin Compatible with the SN75180
  • Available in 14-Lead PDIP and SO Packages
Typical Application
LTC491 Typical Application
  • Low Power RS485/RS422 Transceiver
  • Level Translator
LTC491 Package Drawing
Order Information
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Reliability Data
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LTC491 Footprints and Symbols