Features and Benefits
- Precision Propagation Delay Over Temperature:
- Receiver/Driver: 18.5ns ±3.5ns
- High Data Rate: 52Mbps
- Low tPLH/tPHL Skew:
- Receiver/Driver: 500ps Typ
- –7V to 12V RS485 Input Common Mode Range
- Guaranteed Fail-Safe Receiver Operation Over the Entire Common Mode Range
- High Receiver 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 LTC485
- 45dB CMRR at 26MHz
The LTC1685 is a high speed, precision delay RS485 transceiver that can operate at data rates as high as 52Mbps. The device also meets 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 LTC1685 RS485 transceiver guarantees receiver fail-safe operation over the entire common mode range (–7V to 12V). Input resistance will remain ≥22k when the device is unpowered or disabled.
The LTC1685 operates from a single 5V supply and draws only 7mA of supply current.
- High Speed RS485/RS422 Transceivers
- Level Translator
- Backplane Transceiver
- STS-1/OC-1 Data Transceiver
- Fast-20, Fast-40 SCSI Transceivers
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
The EVAL-RS485HDEBZ allows quick and easy evaluation of half-duplex RS-485 transceivers with standard 8-lead SOIC footprints. The evaluation board allows interfacing via screw terminal block to digital I/O for driver input (DI), receiver output (RO), driver enable (DE) and receiver output (RO). Bus signals A and B (half-duplex bus) can be connected to a bus screw terminal block. One or two termination resistors can be connected to A and B via jumper settings, in order to evaluation the half-duplex RS-485 driver and receiver. Footprints are provided for pull-up and pull-down (biasing resistors) on the bus.
Devices for evaluation on the board must be ordered separately.
Documentation & Resources
R345 Reliability Data3/22/2018
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.