LTC1688 100Mbps RS485 Hot Swapable Quad Drivers

Product Details

The LTC1688/LTC1689 are ultrahigh speed, differential bus/line drivers that can operate at data rates up to 100Mbps. Propagation delay is guaranteed at 8ns ±4ns over the full operating temperature range. These devices operate over the full RS485 common mode range (–7V to 12V), and also meet RS422 requirements.

The driver outputs are Hot Swap capable, maintaining backplane data integrity during board insertion and removal. The drivers feature three-state outputs, maintaining high impedance over the entire common mode range (–7V to 12V). Outputs also remain high impedance during power-up and with the power off. A short-circuit feature detects bus contention and substantially reduces driver output current. Thermal shutdown circuitry protects the parts from excessive power dissipation.

The LTC1688 allows all four drivers to be enabled together, while the LTC1689 allows two drivers at a time to be enabled.

The LTC1688/LTC1689 operate from a single 5V or 3V supply and draw only 9mA of supply current.


  • High Speed RS485 Twisted-Pair Drivers
  • High Speed Backplane Drivers
  • Complementary Clock Drivers
  • STS-1/OC-1 Data Drivers
  • SCSI Drivers

Features and Benefits

  • Ultrahigh Speed:100Mbps
  • Guaranteed Propagation Delay: 8ns ±4ns Over Temperature
  • Low Channel-to-Channel Skew: 500ps Typ
  • Hot Swap Capable
  • 50Mbps Operation with VDD = 3V
  • Low tPLH/tPHL Skew: 500ps Typ
  • Driver Outputs Maintain High Impedance in Three-State or with Power Off
  • Short-Circuit Protected: 3mA Typ Output Current for an Indefinite Short
  • Thermal Shutdown Protected
  • Single 5V or 3V Supply
  • Pin Compatible with LTC486/LTC487