Analog Devices Inc./Maxim Integrated MAX7349AEG

Overview

MAX7349AEG from Maxim Integrated is a 24-pin QSOP I²C-interfaced key-switch and sounder controller designed for high-reliability human-interface management. It monitors up to 64 metallic or resistive (≤1kΩ) key switches using static matrix scanning, debounces events with user-configurable 9–40ms timing, maintains an 8-deep FIFO, and integrates a programmable tone generator supporting 14 musical frequencies (523–2637Hz) for key-click or alarm feedback. It operates from 2.4V to 3.6V across –40°C to +125°C and delivers ≤10µA shutdown current.

For engineers reviewing the MAX7349AEG datasheet, MAX7349AEG pinout, MAX7349AEG application, or MAX7349AEG equivalent, this page provides verified technical context, exact pin functions, real-world use cases in medical panels and industrial controls, and two validated alternative parts with documented functional trade-offs.

Technical Context

The MAX7349AEG implements static key-matrix monitoring-no dynamic scanning-to minimize EMI emissions during operation. Its I²C interface supports 400kbps data rates with 5.5V-tolerant SDA/SCL pins and four selectable slave addresses via AD0 pin configuration (GND/V+/SDA/SCL).

It features dual-function column pins (COL2–COL7/PORT2–PORT7) that serve as either key matrix outputs or open-drain GPOs-up to six can be repurposed, reducing key capacity by eight per GPO. The dedicated SOUNDER output is push-pull, capable of driving piezo transducers, relays, or lamps with programmable frequency, duration, and waveform polarity.

Key Specifications

Pinout & Package

The MAX7349AEG is housed in a 24-pin QSOP package (package code E24-1), with exposed paddle internally connected to GND for thermal performance. Pin functions are validated per Maxim's official datasheet Rev 5 (19-3556).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar key-switch and sounder controller applications.

Compared with MAX7349AEG, MAX7348AEP+ offers reduced key capacity and no ALERT capability but shares identical I²C protocol and tone engine; TCA9554PWR provides basic I/O expansion only and cannot replace MAX7349AEG's integrated key-scan and sounder functions.

Availability

MAX7349AEG is available at Aetrix Electronics and suitable for medical instrument panels, industrial control terminals, security access keypads, and test & measurement equipment requiring stable component supply across extended temperature and voltage ranges.

Supply support for MAX7349AEG includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for demanding industrial, medical, and automotive applications.

The MAX7349AEG belongs to Maxim's low-EMI key-scan controller product line, engineered specifically for EMI-sensitive human-interface systems requiring integrated debouncing, FIFO buffering, and programmable audio feedback without MCU resource overhead.

FAQ

What is the maximum number of keys the MAX7349AEG can monitor?

The MAX7349AEG can monitor up to 64 key switches arranged in an 8×8 matrix. This capacity is achieved using static row/column scanning - not dynamic multiplexing - ensuring minimal EMI generation. Each key must be metallic or resistive with ≤1kΩ contact resistance. Using any of the six configurable COL/PORT pins as general-purpose outputs reduces the maximum key count by eight per pin repurposed.

Does the MAX7349AEG support I²C bus timeout, and how is it configured?

Yes, the MAX7349AEG includes a configurable 20ms minimum bus timeout to prevent lockup if the SCL line stalls. It is enabled or disabled by writing to bit 0 of the Configuration register (address 0x04). When enabled, the device terminates incomplete I²C transactions if the time between adjacent SCL edges exceeds 20ms, then waits for a valid START condition before resuming communication - a critical reliability feature for industrial bus environments.

Can the INT pin on the MAX7349AEG be used as a general-purpose output?

Yes, the INT pin on the MAX7349AEG can be reconfigured as an open-drain general-purpose output (GPO) instead of an interrupt signal. This is controlled via the Interrupt register (address 0x03): clearing bit 0 disables interrupt mode and places INT in high-impedance state, allowing external pull-up to drive LEDs or other loads. The pin retains its ability to sink up to 10mA, matching the VOL specification of ≤0.15V at 10mA sink current.

What are the sounder output capabilities of the MAX7349AEG?

The MAX7349AEG's SOUNDER pin is a push-pull driver supporting both AC tone generation (14 programmable frequencies from 523.25Hz to 2637Hz) and DC output (programmable high/low for duration). It drives piezo transducers directly and can also operate relays or lamps. Sound duration is adjustable in seven binary steps from 15.625ms to 1s, and dual-tone sequences autoloop without host CPU involvement - enabling complex alarm patterns with minimal firmware overhead.

How does the ALERT input function on the MAX7349AEG?

The ALERT input is exclusive to the MAX7349AEG and functions as a hardware-triggered event pin. On each falling edge, it can generate an interrupt (via INT pin), trigger a programmable sound (using Alert Sound register 0x07), or both - all independently of host polling. Its logic state is readable via the Alert Status register, enabling tamper detection, emergency stop signaling, or auxiliary input handling without consuming MCU GPIO or timer resources.