Analog Devices Inc./Maxim Integrated MAX7349AEG+

Overview

MAX7349AEG+ from Maxim Integrated is a 24-pin QSOP I²C key-switch and sounder controller IC that monitors up to 64 metallic or resistive switches (≤1kΩ), debounces key events with user-configurable 9–40ms timing, maintains an 8-deep FIFO, and integrates a programmable piezo tone generator for key-click feedback or alarms. It operates from 2.4V to 3.6V across –40°C to +125°C and features six configurable open-drain GPOs plus an ALERT input.

For engineers reviewing the MAX7349AEG+ datasheet, MAX7349AEG+ pinout, MAX7349AEG+ application, or MAX7349AEG+ equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in medical and industrial panels, and validated alternative parts - all grounded in Maxim's official documentation and electrical specifications.

Technical Context

The MAX7349AEG+ implements static matrix scanning (not dynamic row/column multiplexing) to minimize EMI emissions during key monitoring. Its dual-function architecture separates key-scan control (with interrupt/FIFO management) from independent sounder control (using a dedicated slave address and double-buffered command queue).

It supports four I²C slave addresses via AD0 configuration (GND/V+/SDA/SCL), includes selectable 20–68ms bus timeout, and allows INT pin reconfiguration as a general-purpose open-drain output. The sounder output is push-pull capable of driving piezo transducers, relays, or lamps at frequencies from 523.25Hz to 2637Hz with ±1.2% accuracy.

Key Specifications

Pinout & Package

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 pin description table and schematic reference.

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+ reduces key capacity and removes ALERT functionality but lowers cost and power; TCA9554PWR offers no integrated key-scan or audio capability, shifting full responsibility to the host MCU and increasing design effort and latency.

Availability

MAX7349AEG+ is available at Aetrix Electronics and suitable for medical instrument panels, industrial control consoles, security access keypads, and test & measurement equipment requiring stable component supply across extended temperature and long product lifecycles.

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 - emphasizing reliability, low noise, and extended temperature operation.

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

FAQ

What is the maximum number of keys supported by the MAX7349AEG+?

The MAX7349AEG+ supports up to 64 key switches arranged in an 8×8 matrix. This capacity is achieved using static row/column monitoring - not time-multiplexed scanning - ensuring minimal EMI generation. Each key can be metallic or resistive (up to 1kΩ), and all key events are debounced and queued in an 8-deep FIFO. The MAX7349AEG+ is the highest-capacity variant in the MAX7347/MAX7348/MAX7349 family.

Does the MAX7349AEG+ include a built-in tone generator?

Yes, the MAX7349AEG+ integrates a dedicated piezo sounder controller with 14 programmable musical frequencies ranging from 523.25Hz to 2637Hz - covering the entire 5th musical octave plus seven additional notes. It supports automatic key-click sounds, single/dual-tone alarms, and DC-level output for relays or lamps. The sounder operates via a separate I²C slave address and uses double-buffered commands to eliminate click artifacts during transitions.

What is the function of the ALERT pin on the MAX7349AEG+?

The ALERT pin on the MAX7349AEG+ is a dedicated logic input that triggers both an interrupt and/or a programmable sound on each falling edge - a feature exclusive to the MAX7349AEG+ (not present on MAX7347/MAX7348). Its state is readable as a status bit, and it can be tied to external safety circuits (e.g., emergency stop buttons) to initiate immediate audible and processor-notified responses without host polling.

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

Yes, the INT pin on the MAX7349AEG+ is configurable as either an active-low open-drain interrupt output or a general-purpose open-drain logic output (GPO). When repurposed as a GPO, it adds a seventh controllable output alongside the six COL/PORT pins. This flexibility allows designers to trade interrupt functionality for additional LED drive or system signaling capability - all under register control without hardware change.

What are the I²C voltage and speed specifications for the MAX7349AEG+?

The MAX7349AEG+ supports a 400kbps I²C interface with 5.5V-tolerant SDA and SCL pins - enabling direct connection to 5V microcontrollers without level shifters. Its I²C implementation includes selectable bus timeout (20–68ms), four slave address options (via AD0 pin), and dual-address architecture: one for key-scan registers (0x48–0x4F) and another for sounder control (0x40–0x47). This ensures robust, conflict-free communication in multi-device systems.