ADM1485AR

Overview

The ADM1485AR is a differential line transceiver designed for high-speed bidirectional data communication on multipoint bus transmission lines. It complies with EIA RS-485 and RS-422 standards, featuring one driver and one receiver within an 8-Lead SOIC package. The device operates from a single 5 V power supply with a typical current consumption of 2.2 mA when enabled. It supports data rates up to 30 Mbps, with driver propagation delays as low as 10 ns and receiver delays at 15 ns. The component functions over the industrial temperature range of -40°C to +85°C.

Feature Summary

• Thermal shutdown protection prevents excessive power dissipation during fault conditions by forcing outputs into a high impedance state.
• Fail-safe receiver design ensures a logic high output state when inputs are unconnected or floating.
• High output impedance when disabled minimizes bus loading effects across the entire common-mode voltage range.

Applications

• Low Power RS-485 Systems
• DTE-DCE Interface
• Packet Switching
• Local Area Networks

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm the exact package type and temperature rating. Confirm RoHS compliance status through the designated Z suffix if required. Ensure the selected variant matches the intended PCB footprint and thermal management requirements before finalizing procurement orders.

Selection Notes

Select this component for applications requiring high-speed data transmission up to 30 Mbps in noisy environments. The integrated thermal shutdown and fail-safe features provide robust operation under fault conditions. Verify that the system design accommodates the single 5 V supply requirement and the specific pinout configuration of the 8-Lead SOIC package.

Part Context

The ADM1485 is part of Analog Devices' RS-485 interface family, fabricated using BiCMOS technology. This process combines low-power CMOS with fast-switching bipolar technology to achieve high performance. The device serves as a superior upgrade alternative to legacy components like the LTC1485, offering improved switching speeds and lower power consumption.

Replacement Considerations

The datasheet identifies the LTC1485 as a predecessor component. Designers should verify pin compatibility and electrical specifications when transitioning between these devices to ensure proper system integration.

FAQ

What is the common-mode voltage range supported by the ADM1485?

The ADM1485 supports a bus common-mode range from –7 V to +12 V.

How does the device handle input faults?

The receiver includes a fail-safe feature that results in a logic high output state if the inputs are unconnected or floating.

What protection mechanisms are included in the driver circuitry?

The device features thermal shutdown protection to prevent excessive power dissipation and short-circuit protection for the driver outputs.