ADM1485ANZ

Overview

The ADM1485ANZ 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 PDIP package. The device operates from a single 5 V power supply with a typical data rate of 30 Mbps. Driver propagation delay is typically 10 ns, while receiver propagation delay is typically 15 ns. The common-mode range spans –7 V to +12 V. Operating temperature ranges from –40°C to +85°C.

Feature Summary

• Thermal shutdown protection prevents excessive power dissipation during fault conditions by disabling the driver output when die temperature reaches 150°C.
• Fail-safe receiver feature guarantees a logic high output state if the inputs are unconnected or floating.
• High output impedance when disabled or powered down minimizes loading effects on the bus 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. Ensure that the component meets RoHS compliance requirements if applicable to your manufacturing process. Cross-reference the datasheet revision history to confirm that specifications have not changed since the version referenced in your design documents.

Selection Notes

Select this component for applications requiring high-speed data rates up to 30 Mbps over multipoint buses. Consider the industrial temperature range and the 8-Lead PDIP package constraints. Evaluate the need for thermal shutdown and fail-safe features relative to the system's noise immunity and fault tolerance requirements.

Part Context

The ADM1485 series includes variants such as the ADM1485JNZ for commercial temperatures and the ADM1485ARMZ for surface mount applications. The ANZ designation specifically denotes the industrial temperature range variant housed in an 8-Lead Plastic Dual In-Line Package (PDIP). This part serves as a superior upgrade for legacy components like the LTC1485.

Replacement Considerations

The datasheet identifies the ADM1485 as a superior upgrade for the LTC1485. Verify pin compatibility and electrical characteristics before substituting other RS-485 transceivers.

FAQ

What happens if the driver outputs are shorted?

The ADM1485 includes short-circuit protection. If a significant temperature increase is detected due to output shorting, the thermal shutdown circuit forces the driver output into a high impedance state.

How does the receiver behave when inputs are open?

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

Can multiple drivers be enabled simultaneously?

While up to 32 transceivers may be connected to a bus, only one driver should be enabled at any time to prevent bus contention.