MAX7359ETG+TG05

Specialized Overview

The MAX7359ETG+ is a 2-wire interfaced low-EMI key switch controller and general-purpose output device manufactured by Analog Devices Inc./Maxim Integrated. It provides microprocessors with management of up to 64 key switches, generating unique codes for each press and release event. The device operates on a supply voltage ranging from +1.62V to +3.6V and supports I2C communication at speeds up to 400kbps with 5.5V-tolerant inputs. Key features include static matrix monitoring for low electromagnetic interference, autosleep and autowake capabilities to minimize power consumption, and a FIFO queue capable of storing up to 16 debounced key events. The component is housed in a 24-pin TQFN package (3.5mm x 3.5mm) and functions reliably within an operating temperature range of -40°C to +85°C.

Specialized Feature Summary

• Static matrix monitoring ensures low-EMI operation while supporting metallic or resistive switches up to 5kΩ resistance.
• Autosleep and autowake mechanisms significantly reduce current consumption by entering low-power states during inactivity.
• Configurable interrupt outputs allow alerts based on FIFO levels or definable time periods to prevent processor overload.
• Up to seven open-drain logic outputs can be configured as general-purpose outputs capable of driving LEDs.

Specialized Applications

• Cell phones
• PDAs
• Handheld games
• Portable consumer electronics

Specialized Procurement Notes

Verify the specific ordering suffix against official manufacturer documentation to confirm package type and environmental compliance. Ensure the selected variant matches the required thermal performance and pin configuration for the target PCB layout. Cross-reference the part number with authorized distributors to confirm availability and authenticity before finalizing procurement plans.

Specialized Selection Notes

Select this component when designing systems requiring efficient management of large key matrices with minimal electromagnetic interference. Consider the available GPO configurations if LED driving capabilities are needed alongside key scanning. Evaluate the power budget to determine if the autosleep and autowake features sufficiently meet the standby current requirements of the portable application.

Specialized Part Context

The MAX7359 belongs to the Maxim Integrated family of specialized interface ICs designed for portable consumer electronics. It addresses the need for robust key scanning solutions that do not interfere with sensitive RF circuits. The device integrates debounce logic and event queuing to offload processing tasks from the main microcontroller, simplifying system architecture.

Specialized Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Verify compatibility with existing firmware and hardware interfaces before considering alternative components from other manufacturers.

Specialized FAQ

How does the MAX7359 achieve low-EMI operation?

The device monitors the key matrix statically rather than dynamically. This approach minimizes switching noise and allows the key matrix traces to be routed closer to sensitive circuit nodes without causing electromagnetic interference.

What happens to the FIFO data when the device enters sleep mode?

The content of the FIFO is maintained while the MAX7359 is in sleep mode. The data can still be read via the I2C interface even when the device is in the low-power state.

Can unused column drivers be repurposed?

Yes, any of the column drivers (COL2/PORT2 through COL7/PORT7) or the INT pin, if not used for their primary functions, can be configured as general-purpose outputs (GPO).