Analog Devices Inc./Maxim Integrated MAX7347AEE+T

Overview

The MAX7347AEE+T from Maxim Integrated is a 2-wire (I²C) interfaced key-switch and sounder controller IC designed for low-EMI static matrix scanning of up to 24 metallic or resistive switches (≤1kΩ), with integrated 8-deep FIFO debouncing, user-configurable 9ms–40ms debounce time, and programmable key autorepeat. It operates from 2.4V to 3.6V over –40°C to +125°C and delivers audible feedback via its push-pull SOUNDER output-used in medical instrument front panels requiring reliable tactile response without EMI interference.

For engineers reviewing the MAX7347AEE+T datasheet, MAX7347AEE+T pinout, MAX7347AEE+T application, or MAX7347AEE+T equivalent, this device serves as a dedicated, non-scanning key management solution where deterministic timing, minimal radiated emissions, and integrated audio feedback are critical-especially when replacing discrete GPIO-based switch monitoring or legacy scan controllers.

Technical Context

The MAX7347AEE+T implements static (non-scanned) row/column key matrix monitoring using eight ROW inputs and three COL/PORT outputs (COL0, COL1, COL2/PORT2), enabling up to 24-key detection without clocked scanning artifacts. Its I²C interface supports 400kbps operation with 5.5V-tolerant pins, selectable bus timeout (20–68ms), and four slave address options via AD0 pin configuration.

It integrates two independent functional blocks: a key-scan controller with interrupt-driven FIFO event reporting (INT pin configurable as open-drain GPO), and a dedicated sounder controller with 14 programmable musical frequencies (523Hz–2637Hz), push-pull output capable of driving piezo transducers, relays, or lamps-accessed via a separate I²C slave address.

Key Specifications

Pinout & Package

MAX7347AEE+T is housed in a 16-pin QSOP (E16-4) package with exposed paddle internally connected to GND for thermal performance. Pin functions are validated per Maxim's official pin description table and datasheet Figure 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar key-switch interface applications.

Compared with MAX7347AEE+T, MAX7348AEP+ offers higher key density and added alert functionality in a pin-compatible 20-pin footprint, while TCA9554PWR provides basic I²C GPIO expansion without any key-specific features-making MAX7347AEE+T uniquely suited for EMI-constrained, self-contained key-and-audio systems.

Availability

MAX7347AEE+T is available at Aetrix Electronics and suitable for medical instrumentation, industrial control panels, security access systems, and test equipment requiring stable component supply across extended temperature and long product lifecycles.

Supply support for MAX7347AEE+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) is a semiconductor company specializing in precision analog, mixed-signal, and power management ICs for demanding industrial, medical, and automotive applications.

The MAX7347/MAX7348/MAX7349 family was designed specifically for EMI-sensitive human-interface applications-delivering integrated key scanning, debouncing, FIFO buffering, and audio feedback in a single low-power I²C device.

FAQ

What is the maximum number of keys supported by the MAX7347AEE+T?

The MAX7347AEE+T supports up to 24 key switches using an 8-row × 3-column static matrix configuration. Unlike scanned matrices, it monitors all rows and columns simultaneously-eliminating timing-related EMI and ensuring deterministic key detection. This capacity is fixed for the MAX7347AEE+T variant and cannot be expanded beyond 24 keys without changing to MAX7348AEP+ or MAX7349AEG+.

Does the MAX7347AEE+T include a built-in tone generator?

No, the MAX7347AEE+T does not include a tone generator. Tone generation is exclusive to the MAX7348 and MAX7349 variants. The MAX7347AEE+T retains the SOUNDER pin as a push-pull output capable of driving piezo transducers, relays, or lamps with programmable DC levels-but lacks frequency synthesis circuitry for musical tones or key-click sounds.

Can the INT pin on the MAX7347AEE+T be used as a general-purpose output?

Yes, the INT pin on the MAX7347AEE+T can be reconfigured via the Configuration register (address 0x04) as an open-drain general-purpose output (GPO). When configured as GPO, it retains the same electrical characteristics-≤0.15V VOL at 10mA sink-and can directly drive LEDs or interface with other logic inputs, providing flexibility when interrupt signaling is not required.

What is the operating temperature range for the MAX7347AEE+T?

The MAX7347AEE+T is rated for continuous operation from –40°C to +125°C. This extended industrial temperature range is validated across all electrical specifications-including supply current, key-switch source voltage (0.35V–0.65V), and SOUNDER output drive-making it suitable for under-hood automotive modules, industrial PLCs, and medical devices requiring reliability in harsh thermal environments.

How does the MAX7347AEE+T handle key debouncing?

The MAX7347AEE+T performs hardware-based key debouncing with user-configurable timing from 9ms to 40ms per key, stored in the Debounce register (0x01). It uses static monitoring-no clocked scanning-so each key transition is sampled continuously and validated against the debounce window before being entered into the 8-deep FIFO. This eliminates firmware dependency and ensures consistent behavior across voltage and temperature.