MAX7311AUG+

Overview

The MAX7311AUG+ is a 2-wire-interfaced expander providing 16-bit parallel input/output (I/O) port expansion for SMBus and I2C applications. It operates from a supply voltage of 2V to 5.5V with typical standby current of 2.9µA at 3.3V. The device features a 400kbps I2C-compatible serial interface, 5V overvoltage tolerant I/Os, and supports hot insertion. It includes 16 I/O pins that default to inputs on power-up, each with a 100kΩ pullup. The component is housed in a 24-pin TSSOP package and is specified over the -40°C to +125°C temperature range.

Feature Summary

• Provides 16-bit parallel I/O port expansion controlled via an I2C-compatible serial interface.
• Supports hot insertion with high-impedance state maintained on all pins during power-down.
• Includes bus timeout functionality to prevent lock-up-free operation on the serial bus.
• Features polarity inversion registers allowing system masters to invert input data logic.

Applications

• Servers
• RAID Systems
• Industrial Control
• Medical Equipment
• PLCs

Procurement Notes

Verify the specific ordering suffix AUG+ corresponds to the 24-pin TSSOP package and the -40°C to +125°C automotive temperature range as documented in the official Maxim Integrated datasheet. Confirm compliance with RoHS directives indicated by the plus sign in the part number. Ensure the procurement source provides valid traceability documentation consistent with Analog Devices Inc./Maxim Integrated manufacturing standards.

Selection Notes

Select the MAX7311AUG+ when 16 bidirectional I/O lines are required alongside interrupt capabilities and hot-swap protection. This variant is appropriate for designs needing a TSSOP footprint with a 4.40mm body width. Consider the internal 100kΩ pullups if external resistors are undesirable. Verify that the system master can accommodate the 64 available slave ID addresses configured via AD0–AD2 pins.

Part Context

The MAX7311 series serves as a general-purpose GPIO peripheral for microcontroller systems requiring expanded I/O through standard two-wire interfaces. The MAX7311AUG+ specifically denotes the TSSOP package version within this family. It complements other expanders like the MAX7312, which lacks internal pullups. The device integrates configuration, output, input, and polarity inversion registers into a compact 24-pin form factor suitable for space-constrained industrial and server applications.

Replacement Considerations

The MAX7312 is a related component offering similar I/O expansion but without internal pullup resistors. Direct pin-to-pin replacement requires verifying if the application design relies on the MAX7311's integrated 100kΩ pullups or if external resistors are already present. Other I2C expanders may require significant schematic and firmware modifications due to differing register maps and electrical characteristics.

FAQ

How does the MAX7311 handle hot insertion?

All port pins, the INT output, SDA, SCL, and address inputs remain high impedance with up to 6V asserted on them when V+ is 0V, allowing safe hot insertion.

What is the function of the bus timeout register?

The bus timeout feature resets the serial bus interface if SCL or SDA is held low for more than 29ms after a valid transfer start, preventing lock-ups.

Can the MAX7311 invert input data polarity?

Yes, the system master can invert the input data by writing to the active-high polarity inversion registers for either Port 1 or Port 2.