Features: Precision Propagation Delay Over Temperature:
Receiver/Driver: 18.5ns ±3.5ns
High Data Rate: 52Mbps
Low tPLH /t PHL 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 26MHzApplicationHigh Speed RS485/RS422 Full Duplex Transceivers
Level Translator
Backplane Transceiver
STS-1/OC-1 Data Transceiver
Signal RepeatersPinout
SpecificationsSupply Voltage (VDD )............................................... 10V
Control Input Currents...................... 100mA to 100mA
Control Input Voltages.................. 0.5V to V DD + 0.5V
Driver Input Voltages.................... 0.5V to VDD + 0.5V
Driver Output Voltages ................................... +12V/7V
Receiver Input Voltages................................... +12V/7V
Receiver Output Voltages ............. 0.5V to VDD + 0.5V
Receiver Input Differential ........................................ 10V
Driver Short-Circuit Duration
(VOUT: 7V to 10V)............................................Indefinite
Receiver Short-Circuit Duration
(VOUT : 0V to VDD ).............................................Indefinite
Operating Temperature Range.................... 0°C to 70°C
Storage Temperature Range................ 65°C to 150°C
Lead Temperature (Soldering, 10 sec)...................... 300
Description
The LTC (R)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 of LTC1686/LTC1687 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 22k when the device is unpowered or disabled.
The LTC1686/LTC1687 operate from a single 5V supply and draw only 7mA of supply current.
LTC1687 Data Sheet
