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Analog Devices Inc./Maxim Integrated MAX7349ATG+
- Part No.:
- MAX7349ATG+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Specialized
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
MAX7349ATG+.pdf
- Description:
- IC INTERFACE SPECIALIZED 24TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,818
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Product details
Overview
The MAX7349ATG+ from Maxim Integrated is a 24-pin TQFN-EP I²C-interfaced key-switch and sounder controller designed for static matrix scanning of up to 64 metallic or resistive (≤1kΩ) switches, with integrated 14-tone musical sounder output (523.25Hz–2637Hz), FIFO-based debouncing (8-event depth), and six configurable open-drain GPOs. It operates from 2.4V to 3.6V across –40°C to +125°C and is used in medical instrument front panels requiring low-EMI tactile feedback.
For engineers reviewing the MAX7349ATG+ datasheet, MAX7349ATG+ pinout, MAX7349ATG+ application, or MAX7349ATG+ equivalent, this page delivers verified specifications, validated pin functions, real-world use cases in safety-critical UIs, and confirmed alternative parts with documented functional trade-offs - all grounded in Maxim's official MAX7349 datasheet Rev 5.
Technical Context
The MAX7349ATG+ implements static (non-scanned) key monitoring to eliminate EMI from row/column multiplexing, using dedicated ROW0–ROW7 and COL0–COL7/PORT7 pins to form an 8×8 switch matrix. Its dual-address I²C interface separates key-scan control (0x48–0x4F) from sounder command execution (0x50–0x57), enabling concurrent configuration without bus contention.
It integrates a push-pull SOUNDER output capable of driving piezo transducers or relays, plus an ALERT input (MAX7349-specific) that triggers interrupt and/or tone generation on falling edge. The INT pin is reconfigurable as a seventh GPO, and all six PORT2–PORT7 outputs support LED-driving sink currents up to 25mA at ≤0.15V VOL.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Key Switches | 64 keys via 8-row × 8-column static matrix - eliminates dynamic scan noise and simplifies PCB routing near sensitive analog sections. |
| Supply Voltage Range | 2.4V to 3.6V - compatible with modern low-voltage microcontrollers and battery-backed systems without level-shifting. |
| FIFO Depth | 8 debounced key events - prevents loss during burst presses and enables deterministic polling without interrupt latency concerns. |
| SOUNDER Frequency Range | 523.25Hz to 2637Hz across 14 programmable tones - covers full 5th musical octave plus alarm notes for audible UI feedback. |
| I²C Bus Speed | Up to 400kbps with 5.5V-tolerant inputs - supports fast host communication while interfacing safely with 5V logic domains. |
| Debounce Time | User-configurable 9ms to 40ms - allows tuning for mechanical switch bounce characteristics without firmware overhead. |
| Shutdown Current | ≤10µA - enables ultra-low-power operation in always-on medical or security panels with wake-on-keypress capability. |
Pinout & Package
MAX7349ATG+ uses a 24-pin TQFN-EP package (exposed paddle, 4mm × 4mm, 0.5mm pitch) with thermal pad internally connected to GND. Pinout optimized for compact front-panel integration with separate key matrix and sounder signal routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ROW0–ROW7 | Key matrix row inputs | Static high-impedance inputs accepting open/closed switch states - no external pull-ups required; driven by internal 28–40µA current sources. |
| COL0–COL7/PORT7 | Column outputs / general-purpose open-drain outputs | Configurable as key matrix column drivers (active-low) or GPOs (sink up to 25mA); COL2–COL7 double as PORT2–PORT7 when key count reduced. |
| SOUNDER | Piezo/relay driver output | Push-pull output delivering programmable square-wave tones or DC high/low for lamps/relays - no external driver needed. |
| ALERT | Edge-triggered logic input | MAX7349-exclusive input generating interrupt and/or tone on falling edge; readable via register - adds hardware-triggered alarm capability. |
| INT | Active-low interrupt / configurable GPO | Open-drain output signaling key press, FIFO level, or timer expiry; can be reassigned as seventh GPO when interrupts not required. |
| SDA/SCL/AD0 | I²C data/clock/address | 5.5V-tolerant, 400kbps I²C interface with four selectable slave addresses (via AD0 tied to GND/V+/SDA/SCL) - supports up to four devices on one bus. |
Key Features
| Feature | Design Value |
|---|---|
| Low-EMI static key monitoring | Eliminates switching noise from dynamic matrix scanning - critical for ECG, EEG, and precision instrumentation where RF interference must be minimized. |
| Dual I²C slave addresses | Separate 7-bit addresses for key-scan (0x48–0x4F) and sounder (0x50–0x57) peripherals - enables independent register access without command collision or timing conflicts. |
| Programmable sounder duration | Seven binary steps from 15.625ms to 1s - allows precise tuning of key-click length or alarm pulse width without CPU intervention. |
| Alert input with dual-action response | Hardware-level falling-edge detection triggering both interrupt and tone generation - reduces firmware complexity for emergency panel alerts. |
| Bus timeout protection | 20ms minimum SCL edge-to-edge timeout - prevents lockup if master hangs, ensuring system recoverability in industrial environments with noisy power rails. |
| Reconfigurable INT pin | Switchable between interrupt output and open-drain GPO - increases GPIO flexibility in space-constrained designs without adding discrete logic. |
Applications
| Medical Instrument Panels | Industrial Control Interfaces |
|---|---|
Use Scenario: Front-panel keypad on portable ultrasound or infusion pump with audible key feedback and EMI-sensitive analog front-end. IC Role / Device Role / Timing Role: Central key-scan and audio feedback controller managing 64-button matrix and piezo transducer, synchronized via I²C to host MCU. Use Value: Static scanning avoids radiated emissions that could corrupt ADC readings; 14-tone generator provides distinct, non-distracting auditory cues compliant with IEC 60601-1. |
Use Scenario: Operator console for factory automation PLC with metal pushbuttons, status LEDs, and alarm buzzer. IC Role / Device Role / Timing Role: Unified interface handling button debouncing, LED drive (via PORT2–PORT7), and alarm tone generation - reducing BOM count vs. discrete solutions. Use Value: Six GPOs drive indicator LEDs directly; SOUNDER output toggles relay for loud horn - eliminating need for external drivers or timers. |
| Security Access Keypads | Test & Measurement Equipment |
Use Scenario: Tamper-resistant entry keypad for biometric door locks requiring secure, low-power wake-on-keypress and audible confirmation. IC Role / Device Role / Timing Role: Low-quiescent-current (≤10µA shutdown) key monitor with ALERT input wired to tamper switch - triggers immediate tone + interrupt on cover removal. Use Value: Hardware-based tamper response bypasses software delays; FIFO ensures no keypress lost during wake-up sequence. |
Use Scenario: Benchtop oscilloscope or spectrum analyzer with membrane keypad and status indicators. IC Role / Device Role / Timing Role: Interface between 64-key overlay and ARM Cortex-M host, providing debounced key data, LED control, and soft-tone navigation feedback. Use Value: I²C address flexibility (4 options) allows stacking multiple MAX7349ATG+ on same bus for modular front-panel expansion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar key-switch and sounder controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX7348AEP+ | Monitors up to 40 keys (5×8 matrix); lacks ALERT input and COL7/PORT7; 20-pin QSOP only. | Lower key count and no hardware alert trigger - suitable for simpler UIs without tamper detection or 64-key density. | Select when board space permits QSOP and application requires ≤40 keys with tone feedback but no external event-triggered sound. |
| TCA9554PWR | I²C 8-bit GPIO expander only - no key scanning, no debounce, no sounder, no FIFO, no ALERT. | Requires external firmware-driven scanning and tone generation - increases MCU load and design complexity. | Choose only if existing system already handles key debounce in software and needs basic GPIO expansion without audio features. |
Compared with MAX7349ATG+, MAX7348AEP+ reduces key capacity and removes ALERT functionality but retains identical sounder capabilities and temperature range; TCA9554PWR offers GPIO only and shifts all key/sounder logic to host firmware - making MAX7349ATG+ the sole solution integrating full hardware-managed 64-key scanning, 14-tone generation, and edge-triggered alert response.
Availability
MAX7349ATG+ is available at Aetrix Electronics and suitable for medical instrumentation, industrial HMI, security access systems, and test equipment requiring stable component supply across extended temperature and long product lifecycles.
Supply support for MAX7349ATG+ 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 MAX7349ATG+ belongs to Maxim's low-EMI key-switch controller product line, engineered specifically for EMI-sensitive human-interface applications where silent, reliable tactile feedback and robust noise immunity are mandatory.
FAQ
What is the maximum number of keys supported by the MAX7349ATG+?
The MAX7349ATG+ supports up to 64 keys arranged in an 8×8 matrix using static monitoring. This is achieved via eight ROW inputs (ROW0–ROW7) and eight COL/PORT outputs (COL0–COL7/PORT7). Unlike scanned matrices, static monitoring eliminates EMI from sequential row activation - a key advantage in medical and instrumentation applications where signal integrity is critical. The MAX7349ATG+ datasheet explicitly confirms this 64-key capability in Table 1 and the General Description section.
Does the MAX7349ATG+ include a built-in sounder driver?
Yes, the MAX7349ATG+ integrates a dedicated push-pull SOUNDER output capable of generating 14 programmable musical tones (523.25Hz–2637Hz), continuous DC levels for relays/lamps, and dual-tone alarms. It drives piezo transducers directly without external components. The sounder operates independently via its own I²C slave address (0x50–0x57), and its frequency accuracy is ±1.2% at +25°C per the Electrical Characteristics table. This functionality is exclusive to MAX7348/MAX7349 - not present in MAX7347.
Can the INT pin on the MAX7349ATG+ be used as a general-purpose output?
Yes, the INT pin on the MAX7349ATG+ is reconfigurable as an open-drain general-purpose output (GPO) when interrupt functionality is not required. This is controlled via the Configuration register (address 0x04). As a GPO, it can sink up to 25mA at ≤0.15V VOL, sufficient to drive LEDs directly. This flexibility allows designers to gain an additional GPIO without adding discrete logic - a feature confirmed in the Pin Description table and Detailed Description section of the MAX7349ATG+ datasheet.
What is the purpose of the ALERT pin on the MAX7349ATG+?
The ALERT pin is a MAX7349ATG+-exclusive feature that provides hardware-level, falling-edge-triggered response. When asserted, it can simultaneously generate an interrupt and initiate a programmable tone - enabling immediate audible and processor-signaled reaction to events like tamper detection or emergency stop activation. Its state is readable via register, and it operates independently of the key matrix. This capability is absent in MAX7347/MAX7348 and is documented in the Pin Description table and Detailed Description section of the MAX7349ATG+ datasheet.
What package type is used for the MAX7349ATG+?
The MAX7349ATG+ uses a 24-pin TQFN-EP package (4mm × 4mm, 0.5mm pitch) with an exposed thermal paddle internally connected to GND. This package is specified in the Ordering Information table as "T2444-4" and offers superior thermal performance over the 24-pin QSOP variant (MAX7349AEG+). The exposed paddle must be soldered to a large ground plane to ensure reliable operation at +125°C - a requirement emphasized in the Absolute Maximum Ratings and Pin Configurations sections of the MAX7349ATG+ datasheet.
MAX7349ATG+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Sound Cards, Players, Recorders
- Interface:
- I2C
- Voltage - Supply:
- 2.4V ~ 3.6V
- Supplier Device Package:
- 24-TQFN (4x4)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
MAX7349ATG+ FAQ
1.How can I place an order for MAX7349ATG+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX7349ATG+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX7349ATG+ reliable?
The price and inventory of MAX7349ATG+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX7349ATG+ is usually 5 days.
3.What payment methods are accepted for MAX7349ATG+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX7349ATG+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX7349ATG+?
MAX7349ATG+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX7349ATG+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX7349ATG+?
For technical support, including MAX7349ATG+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX7349ATG+ requirements.
6.How does Aetrix verify that MAX7349ATG+ is sourced from the original manufacturer or authorized distributors?
All MAX7349ATG+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX7349ATG+ meets industry standards.
7.What is the process for return or replacement of MAX7349ATG+?
All MAX7349ATG+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX7349ATG+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX7349ATG+ part is unused and in its original packaging.
Return procedure for MAX7349ATG+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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