MAX3291CSD

Overview

The MAX3291CSD is a full-duplex RS-485/RS-422 transceiver featuring driver preemphasis circuitry to reduce intersymbol interference. It operates from a single +5V supply with a typical no-load supply current of 3mA and a shutdown mode current of 100nA. The device supports data rates up to 10Mbps and includes a fail-safe receiver that guarantees a logic-high output when the input is open. It accommodates up to 128 transceivers on the bus due to its 1/4-unit-load receiver input impedance. The unit is housed in a 14-pin SO package and functions within an operating temperature range of 0°C to +70°C.

Feature Summary

• Driver preemphasis circuitry extends reliable communication distance and increases data rate by reducing intersymbol interference caused by long cables.
• Fail-safe receiver input guarantees a logic-high output if the differential input is left open, ensuring defined states during idle conditions.
• Low-current shutdown mode reduces supply current to 100nA when both receiver and driver outputs are disabled.
• 1/4-unit-load receiver input impedance allows connection of up to 128 transceivers on a single communication bus.

Applications

• Long-distance, high-speed RS-485/RS-422 communications
• Telecommunications systems
• Industrial-control local area networks

Procurement Notes

Verify the specific suffix 'CSD' corresponds to the commercial temperature grade (0°C to +70°C) and the 14-pin SO package configuration. Confirm RoHS compliance status through official manufacturer documentation or authorized distributors prior to finalizing procurement orders.

Selection Notes

Select this component for applications requiring extended cable lengths at high data rates where standard transceivers suffer from intersymbol interference. Ensure the system operates on a single +5V supply and requires full-duplex communication capabilities with fail-safe input protection.

Part Context

This part belongs to the MAX3291/MAX3292 family of high-speed RS-485/RS-422 transceivers. The MAX3291 variant features a fixed internal preemphasis interval optimized for data rates between 5Mbps and 10Mbps, distinguishing it from the resistor-programmable MAX3292.

Replacement Considerations

The datasheet lists pin-compatible alternatives including the ’75180, MAX489, MAX491, MAX3080, MAX3083, MAX3086, and MAX1482. Verify functional equivalence regarding preemphasis capabilities and electrical specifications before substitution.

FAQ

How does the MAX3291 handle inter-symbol interference?

It utilizes driver preemphasis circuitry which increases signal amplitude at transition edges to counteract the effects of cable RC time constants, thereby reducing intersymbol interference.

What is the maximum number of devices supported on the bus?

The device features a 1/4-unit-load receiver input impedance, allowing up to 128 transceivers to be connected in parallel on one communication line.

How is the low-power shutdown mode activated?

Shutdown is initiated by driving the Receiver Enable (RE) pin high and the Driver Enable (DE) pin low simultaneously.