Analog Devices Inc./Maxim Integrated MAX7349AEG+T

Overview

The MAX7349AEG+T from Maxim Integrated is a 24-pin QSOP I²C-interfaced key-switch and sounder controller IC designed for high-reliability human-interface management. It monitors up to 64 metallic or resistive (≤1kΩ) key switches using static matrix scanning, debounces events into an 8-deep FIFO, and integrates a programmable piezo sounder driver with 14 musical frequencies (523Hz–2637Hz). It operates from 2.4V to 3.6V across –40°C to +125°C and is used in medical instrument panels requiring low-EMI, audible feedback, and interrupt-driven key event handling.

For engineers reviewing the MAX7349AEG+T datasheet, MAX7349AEG+T pinout, MAX7349AEG+T application, or MAX7349AEG+T equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in safety-critical UIs, and validated alternative parts - all grounded in Maxim's official documentation and electrical specifications.

Technical Context

The MAX7349AEG+T implements static (non-scanned) key matrix monitoring to minimize EMI emissions, with configurable debounce (9ms–40ms) and autorepeat timing. Its dual-address I²C interface uses separate slave addresses for key-scan control (0x48–0x4F) and sounder control (0x40–0x47), both supporting 400kbps operation and 5.5V-tolerant inputs.

It provides six configurable column outputs (COL2/PORT2 through COL7/PORT7) that serve either as key matrix drivers or open-drain GPOs (capable of driving LEDs), plus dedicated SOUNDER (push-pull), ALERT (input-only), and INT (open-drain interrupt or GPO) terminals. The tone generator supports single/dual-tone alarms, programmable duration (15.625ms–1s), and automatic key-click feedback.

Key Specifications

Pinout & Package

MAX7349AEG+T is housed in a 24-pin QSOP (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 typical application circuit.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX7348AEP+, MAX7349AEG+T adds 24 more key positions, ALERT input, three extra GPOs, and broader tone range - justifying its use in complex, safety-aware UIs. Against TCA9554PWR, it eliminates firmware complexity for key/sound tasks but occupies more board space and cost.

Availability

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

Supply support for MAX7349AEG+T 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, mixed-signal, and power-management ICs for demanding industrial, medical, and automotive applications.

The MAX7349AEG+T belongs to Maxim's 2-wire interfaced key-switch and sounder 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 supported by the MAX7349AEG+T?

The MAX7349AEG+T supports up to 64 key switches arranged in an 8×8 matrix. Each key is monitored statically (not dynamically scanned) to ensure low-EMI operation. If any of the six configurable COLx/PORTx pins (COL2–COL7) are repurposed as general-purpose outputs, the maximum key count decreases by eight per pin reassigned - e.g., using two as GPOs reduces capacity to 48 keys. This behavior is documented in Maxim's MAX7349 datasheet Section "Detailed Description" and Table 1.

Does the MAX7349AEG+T include a built-in sounder driver?

Yes, the MAX7349AEG+T integrates a dedicated push-pull SOUNDER output capable of driving piezo transducers, relays, or lamps directly. It supports 14 programmable musical frequencies from 523.25Hz to 2637Hz with ±1.2% accuracy at +25°C, and allows configurable tone duration from 15.625ms to 1s. The sounder operates independently via its own I²C slave address (0x40–0x47), enabling concurrent key-scan and audio control without interference - confirmed in the "Tone Generator" section of the MAX7349AEG+T datasheet.

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

Yes, the INT pin on the MAX7349AEG+T is configurable as either an active-low open-drain interrupt output or an additional general-purpose output (GPO). When configured as a GPO, it can sink up to 25mA and drive LEDs or other logic-level loads. Configuration is performed via the Interrupt register (address 0x03); setting bit D0 = 0 disables interrupt functionality and enables GPO mode. This dual-role capability is explicitly defined in the "Pin Description" and "Registers Description" sections of the MAX7349AEG+T datasheet.

What is the purpose of the ALERT input on the MAX7349AEG+T?

The ALERT input is a dedicated logic input unique to the MAX7349AEG+T (not present on MAX7347/MAX7348) that triggers hardware-level responses on falling edges - including generating a tone, asserting the INT output, or both. Its state is readable via register, and it supports automatic sound generation independent of key presses. This enables external event detection (e.g., door sensor closure or emergency button press) with zero MCU polling overhead - detailed in the "Alert Input" subsection of the MAX7349AEG+T datasheet.

What supply voltage range does the MAX7349AEG+T support?

The MAX7349AEG+T operates from a single supply of 2.4V to 3.6V, with guaranteed performance across the full –40°C to +125°C temperature range. At V+ = 3.3V and TA = +25°C, typical supply current is 100µA during active key monitoring and drops to ≤10µA in shutdown mode. These values are specified in the "ELECTRICAL CHARACTERISTICS" table of the MAX7349AEG+T datasheet and validated over process, voltage, and temperature corners.