POWER AND LINEAR IC SOLUTIONS

Combined RS485/RS422 Transceiver and Power IC

Industrial factories often employ communication systems that require the use of long transmission lines. RS485 is generally the transmission protocol of choice in these scenarios, because of its high degree of ruggedness. However, additional protection is required, because circuits and cabling are exposed to what are often extremely noisy environments.


To eliminate the impact of ground potential differences, it is necessary to isolate the transmitting, receiving and power line elements on each of the noisy system-side components from the transmit, receive and power lines on the shared bus side.

The LTM2881 from Linear Technology is designed to carry out all the essential isolation, power and communication tasks for system designs of this kind so that no external components are required. This completely isolated RS485/RS422 solution utilises the company’s proprietary isolator µModule technology, integrating a 2500VRMS galvanic isolation barrier, a high-performance transceiver and all necessary power components into low-profile LGA and BGA packages.

The LTM2881’s ±15kV ElectroStatic Discharge (ESD) protected transceiver operates at 20Mbit/s or low EMI 250kbit/s in half-duplex or full-duplex configurations. Its 1W DC/DC converter provides surplus current for powering external ICs and LEDs via a 5V regulated output. The device also exhibits a common-mode transient immunity greater than 30kV/µs, allowing it to continue communicating, rather than merely holding a data state, through severe transient events.

An integrated pin-selectable 120Ω termination is available for minimising reflections that may be present on an un-terminated transmission line. This allows the proper nodes to be terminated by switching the integrated termination on or off, under software control, without the need for physical intervention by the user.

Features

• 2500VRMS isolated RS485/RS422 transceiver
• Integrated 1W isolated DC/DC converter (62% efficiency)
• High data rate: 20Mbit/s
• Does not require additional peripheral components
• High common mode transient immunity: 30kV/μs
• Integrated selectable 120Ω termination
• Low-current shutdown mode: < 5μA
• Compact 15mm × 11.25mm × 2.8mm surface mount package

Applications

• Industrial control systems
• Factory automation systems
• Telemetry equipment
• Manufacturer production lines

For further information, to register your interest in a Free Demo Board*, or to obtain a copy of the latest Altera/LTC Development Tools Brochure or the LTM2881 Datasheet, please click here.

* Free demo boards are limited to current or potential Arrow customers with valid opportunities and are at the discretion of local Arrow representatives.

Note: Linear Technology is franchised with Arrow in Denmark, Norway, Sweden, UK and Ireland.