MAX3078EASA+T

Overview

The MAX3078EASA+T is a half-duplex RS-485 transceiver manufactured by Analog Devices Inc./Maxim Integrated. It features one driver and one receiver operating from a single 3.3V supply (2.97V to 3.63V). The device supports data rates up to 16Mbps with unrestricted slew rates. It includes ±15kV ESD protection on I/O pins, fail-safe circuitry ensuring a logic-high output when inputs are open or shorted, and hot-swap capability to prevent false transitions during power-up or insertion. Operating temperature ranges from -40°C to +85°C for the 'E' grade. Supply current is typically 1.5mA.

Feature Summary

• Hot-swap input structure prevents erroneous bus transitions during board insertion or power-up sequences.
• Fail-safe receiver guarantees a logic-high output state when differential inputs are left open or shorted.
• Unrestricted driver slew rate enables high-speed data transmission up to 16Mbps.
• Robust protection against electrostatic discharge with ±15kV Human Body Model tolerance.

Applications

• Industrial control systems
• Telecommunications equipment
• Security and alarm systems
• Instrumentation and measurement devices

Procurement Notes

Verify the specific suffix '+T' indicates tape-and-reel packaging configuration. Confirm the 'E' designation aligns with the required industrial temperature range of -40°C to +85°C. Ensure compatibility with standard 8-pin SOIC footprints during PCB layout review.

Selection Notes

Select this component for applications requiring high-speed half-duplex communication without slew-rate limiting. Verify that the system operates exclusively at 3.3V logic levels. Consider alternative models if full-duplex operation or extended temperature ranges beyond +85°C are required.

Part Context

This part belongs to the MAX3070E–MAX3079E family of 3.3V RS-485 transceivers. Within this series, the MAX3078E is specifically designated for half-duplex communication with maximum data rates up to 16Mbps. It shares common interface standards and protection features with other members of the family while differing in duplex mode and speed capabilities.

Replacement Considerations

Public confirmed substitutes include MAX3078EESA+ and MAX3078EESA/V+. These variants maintain identical electrical specifications and pinouts within the same product family.

FAQ

What is the default receiver output state when the bus is idle?

The fail-safe circuitry ensures the receiver outputs a logic-high state when the receiver inputs are open, shorted, or when all transmitters on a terminated bus are disabled.

How does the device handle hot insertion into a powered backplane?

Internal pull-down and pull-up circuits on the DE and RE pins hold the driver disabled and receiver enabled during power-up, preventing false data transitions caused by leakage currents or parasitic capacitance.

Is the driver slew rate adjustable on the MAX3078E?

No, the MAX3078E has an unrestricted driver slew rate optimized for speeds up to 16Mbps. Slew-rate limiting is only available on other family members like the MAX3070E through MAX3075E via the SRL pin.