LTC1687 - 52Mbps Precision Delay RS485 Fail-Safe Transceivers

The LTC®1686/LTC1687 are high speed, precision delay, full-duplex RS485 transceivers that can operate at data rates as high as 52Mbps. The devices also meet the requirements of RS422. A unique architecture provides very stable propagation delays and low skew over a wide common mode and ambient temperature range. The driver and receiver feature three-state outputs, with disabled driver outputs maintaining high impedance over the entire common mode range. A short-circuit feature detects shorted outputs and substantially reduces driver output current. A similar feature also protects the receiver output from short circuits. Thermal shutdown circuitry protects from excessive power dissipation. The receiver has a fail-safe feature that guarantees a high output state when the inputs are shorted or are left floating. The LTC1686/LTC1687 RS485 transceivers guarantee receiver fail-safe operation over the entire common mode range (–7V to 12V). Receiver input resistance remains ž22k when the device is unpowered or disabled. The LTC1686/LTC1687 operate from a single 5V supply and draw only 7mA of supply current.

Features
  • Precision Propagation Delay Over Temperature: Receiver/Driver: 18.5ns ±3.5ns
  • High Data Rate: 52Mbps
  • Low tPLH/tPLH Skew: Receiver/Driver: 500ps Typ
  • –7V to 12V RS485 Input Common Mode Range
  • Guaranteed Fail-Safe Operation Over the Entire Common Mode Range
  • High Input Resistance: >22k, Even When Unpowered
  • Short-Circuit Protected
  • Thermal Shutdown Protected
  • Driver Maintains High Impedance in Three-State or with Power Off
  • Single 5V Supply
  • Pin Compatible with LTC490/LTC491
  • 45dB CMRR at 26MHz
Typical Application
LTC1687 Typical Application
LTC1687 Typical Application
Applications
  • High Speed RS485/RS422 Full Duplex Transceivers
  • Level Translator
  • Backplane Transceiver
  • STS-1/OC-1 Data Transceiver
  • Signal Repeaters
Packaging
LTC1687 Package Drawing
LTC1687 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC1687CS#PBFSO-14C$5.15$4.20
LTC1687CS#TRPBFSO-14C$4.26
LTC1687IS#PBFSO-14I$5.50$4.75
LTC1687IS#TRPBFSO-14I$4.81
Datasheet
Design Note
Reliability Data
Product Selector Card
CAD Symbol
Related Products
LTC1686/LTC1687 - 52Mbps Precision Delay RS485 Fail-Safe Transceivers
DN168 - RS485 Transceivers Operate at 52Mbps Over 100 Feet of Unshielded Twisted Pair
R345 Reliability Data
RS485 Quick Guide
Ultra Rugged ±60V RS485 Transceivers
LTC1687 Footprints and Symbols