MAX491ESD+T

Drivers, Receivers, Transceivers Overview

The MAX491ESD+T is a low-power, full-duplex RS-485 and RS-422 transceiver manufactured by Analog Devices Inc. under the Maxim Integrated brand. It integrates one driver and one receiver within a 14-pin SOIC package. The device supports data transmission rates up to 2.5Mbps with unrestricted slew rates. It operates from a single 5V supply (4.75V to 5.25V) and draws a typical quiescent current of 300µA. The component features thermal shutdown protection for the driver outputs and includes dedicated Driver Enable (DE) and Receiver Enable (RE) control pins.

Drivers, Receivers, Transceivers Feature Summary

• Full-duplex communication capability with independent driver and receiver enable controls
• High-speed data transmission up to 2.5Mbps without slew-rate limiting
• Integrated thermal shutdown circuitry to protect against excessive power dissipation

Drivers, Receivers, Transceivers Applications

• Low-Power RS-485 Transceivers
• Low-Power RS-422 Transceivers
• Industrial-Control Local Area Networks

Drivers, Receivers, Transceivers Procurement Notes

Verify the specific suffix 'ESD' corresponds to the -40°C to +85°C industrial temperature range and SOIC-14 package configuration. Confirm that the '+T' designation indicates tape-and-reel packaging rather than cut tape or tube formats. Ensure compatibility with standard 5V logic levels before integration into existing bus architectures.

Drivers, Receivers, Transceivers Selection Notes

Select this component when full-duplex operation is required alongside high-speed data rates exceeding 250kbps. Unlike slew-rate-limited variants such as the MAX489, the MAX491 allows faster transitions suitable for longer cables at higher baud rates. Verify that the application does not require the low-current shutdown mode available in half-duplex counterparts like the MAX481.

Drivers, Receivers, Transceivers Part Context

The MAX491 belongs to the broader family of low-power RS-485/RS-422 transceivers, which also includes half-duplex models like the MAX481 and MAX485. While similar devices share the same general description and pinout structures, the MAX491 is distinct due to its full-duplex architecture and 14-pin form factor. This distinguishes it from the 8-pin half-duplex versions within the same product series.

Drivers, Receivers, Transceivers Replacement Considerations

MAX491ESA

Drivers, Receivers, Transceivers FAQ

Does the MAX491 support a low-current shutdown mode?

No, the MAX491 does not feature a low-current shutdown mode. Only the MAX481, MAX483, and MAX487 within this family include this specific low-power feature.

What is the maximum data rate supported by the MAX491?

The MAX491 supports data rates up to 2.5Mbps. Its driver slew rate is not limited, allowing for faster signal transitions compared to the 250kbps slew-rate-limited variants.

How many unit loads can be placed on the bus with the MAX491?

The MAX491 has a standard 1-unit-load receiver input impedance (12kΩ). Consequently, a maximum of 32 transceivers can be placed on the bus, unlike the MAX487/MAX1487 which support 128.