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 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
The LTC1686/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 ≥22k when the device is unpowered or disabled.
The LTC1686/LTC1687 operate from a single 5V supply and draw only 7mA of supply current.
- High Speed RS485/RS422 Full Duplex Transceivers
- Level Translator
- Backplane Transceiver
- STS-1/OC-1 Data Transceiver
- Signal Repeaters
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-RS485FD8EBZ allows quick and easy evaluation of full-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) and receiver output (RO). Bus signals A, B, Y and Z (full-duplex bus) can be connected to a bus screw terminal block. Termination resistors are fitted across A and B, as well as Y and Z. These can be connected in half-duplex configuration (A to Y, B to Z), in order to evaluate the RS-485 driver. Footprints are provided for pull-up and pull-down (biasing resistors) on the receiver inputs in order to provide the option to evaluate an RS-485 receiver with this configuration.
Devices for evaluation on the board must be ordered separately.
Product Selection Guide (1)
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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