MAX3157CAI+T

Overview

The MAX3157CAI+T is a high CMRR RS-485/RS-422 data-communications interface providing ±50V isolation in a hybrid microcircuit. It contains one transmitter and one receiver, operating at data rates up to 250kbps with a single +5V supply. The device features pin-selectable half- or full-duplex modes and independently programmable receiver and transmitter output phases. Supply current typically draws 25mA when unloaded and drops to 25µA in shutdown mode. Drivers are short-circuit current limited and protected by thermal shutdown circuitry. The receiver input includes a fail-safe feature guaranteeing a logic high output if inputs are open or shorted. Operating temperature range is 0°C to +70°C.

Feature Summary

• Provides ±50V isolation using external capacitors for power transfer from the logic side.
• Features true fail-safe receiver operation while maintaining EIA/TIA-485 compliance.
• Includes thermal shutdown protection and driver short-circuit current limiting.
• Offers pin-selectable half/full-duplex operation and independent phase controls.

Applications

• Industrial Controls
• Level Translators
• Telecommunications
• Local Area Networks

Procurement Notes

Verify the specific ordering suffix '+T' against official documentation to confirm tape-and-reel packaging status, as standard datasheets may list bulk variants like 'MAX3157CAI'. Confirm that the component meets RoHS environmental standards and check for any obsolescence notices or product change notifications issued by Analog Devices regarding this specific part number.

Selection Notes

Select this component for applications requiring galvanic isolation between logic and communication lines without optical components. Ensure the system design accommodates the required charge-pump capacitors (C1, C2) for isolated power generation. Verify that the twisted-pair wiring polarity matches the TXP and RXP configurations or utilize the phase control pins to correct for reversed connections.

Part Context

The MAX3157 serves as a low-cost replacement for opto-isolated transceivers in RS-485/RS-422 networks. It belongs to the MAX3157 family, which also includes PDIP packages and extended temperature variants. Unlike fully integrated isolated transceivers such as the MAX1480 family, this device relies on external capacitors for isolation power transfer.

Replacement Considerations

Direct replacements include other MAX3157 variants such as MAX3157EAI for extended temperature ranges or MAX3157CPI for through-hole mounting. For fully integrated solutions without external isolation capacitors, consider the MAX1480 family.