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Analog Devices Inc./Maxim Integrated MAX7347AEE
- Part No.:
- MAX7347AEE
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Specialized
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX7347AEE.pdf
- Description:
- SWITCH AND SOUNDER CONTROLLER
- Quantity:
- Payment:
- Shipping:
Inventory:2,129
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Product details
Overview
The MAX7347AEE 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 across –40°C to +125°C and delivers <10µA shutdown current - ideal for medical instrument front panels and industrial control interfaces requiring reliable tactile feedback and minimal EMI.
For engineers reviewing the MAX7347AEE datasheet, MAX7347AEE pinout, MAX7347AEE application, or MAX7347AEE equivalent, this device serves as a dedicated I²C peripheral for robust key-event management and audible click generation in space-constrained, high-reliability embedded systems - with attention to its fixed I²C address, single sounder output, and 16-pin QSOP package constraints.
Technical Context
The MAX7347AEE implements static (non-scanned) key matrix monitoring to eliminate dynamic switching noise, reducing system-level EMI without sacrificing responsiveness. Its internal architecture separates key-scan logic (with configurable interrupt on FIFO level or event) from a dedicated sounder controller that accepts double-buffered tone commands via a second I²C slave address.
Unlike the MAX7348/MAX7349, the MAX7347AEE lacks ALERT input, COL3–COL7/PORT3–PORT7, and tone generator features - it supports only one fixed I²C address (0x71 for key-scan, no sounder slave ID), and configures its INT pin exclusively as interrupt output (not GPO). Its 16-pin QSOP package maps ROW0–ROW7 and COL0–COL2/PORT2 to discrete matrix connections, with SOUNDER omitted entirely.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Key Inputs | 24 switches max (3×8 matrix via COL0–COL2/PORT2 + ROW0–ROW7); static monitoring eliminates scan clock EMI. |
| Supply Voltage | 2.4V to 3.6V - compatible with 2.5V/3.3V logic domains; bypass required with ≥0.047µF ceramic capacitor at V+. |
| Debounce Time | User-configurable 9ms to 40ms - sets minimum inter-keypress interval to reject mechanical bounce without firmware overhead. |
| FIFO Depth | 8 debounced key events - enables burst handling and reduces host polling frequency; 1-byte read returns event + status. |
| I²C Interface | 400kbps, 5.5V-tolerant; fixed slave address 0x71 (key-scan only); no sounder controller or second slave ID supported. |
| Shutdown Current | <10µA - enables ultra-low-power sleep mode during idle periods in battery-backed or energy-sensitive applications. |
| Operating Temp | –40°C to +125°C - qualified for under-hood automotive, industrial control, and medical equipment environments. |
Pinout & Package
MAX7347AEE is housed in a 16-pin QSOP (E16-4) package with exposed paddle internally connected to GND. Pin functions are validated per Maxim's official datasheet revision 5 (May 2007).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–8 (ROW0–ROW7) | Key matrix row inputs | High-impedance CMOS inputs; connect to switch rows; leave open if unused - no internal pull-ups. |
| 9 (COL2/PORT2) | Column output / GPO | Open-drain output capable of driving LEDs; defaults to column driver; not configurable as GPO on MAX7347AEE. |
| 10 (COL1) | Column output | Dedicated column driver for 3×8 matrix; sinks current when active; requires external pull-up for key detection. |
| 11 (COL0) | Column output | Primary column driver; forms 3-column side of matrix with COL1 and COL2/PORT2. |
| 12 (GND) | Power ground | Reference for all analog/digital circuitry; must connect exposed paddle to large ground plane for thermal performance. |
| 13 (SDA) | I²C bidirectional data | Open-drain I/O; requires 4.7kΩ pull-up; tolerates up to 6V; acknowledges writes/reads at 0x71 address. |
| 14 (SCL) | I²C clock input | CMOS input only; requires 4.7kΩ pull-up in multi-master systems; triggers internal timing for bus timeout (20ms min). |
| 15 (INT) | Active-low interrupt | Open-drain output; asserts on key press/FIFO threshold; cannot be reconfigured as GPO on MAX7347AEE. |
| 16 (V+) | Positive supply | 2.4V–3.6V input; powers all logic and key-scan circuitry; must be decoupled locally to GND. |
Key Features
| Feature | Design Value |
|---|---|
| Low-EMI static key scanning | Eliminates periodic scan clock noise - enables routing near sensitive analog or RF sections without shielding. |
| Configurable interrupt behavior | INT asserts per debounced event or at definable FIFO fill level - prevents interrupt storm while ensuring timely host response. |
| Hardware FIFO buffering | 8-entry queue stores key events with autorepeat support - decouples host processing latency from real-time key capture. |
| Robust I²C interface | 5.5V-tolerant SDA/SCL pins and selectable 20–68ms bus timeout - recovers gracefully from hung clocks or master faults. |
| Ultra-low shutdown current | <10µA quiescent draw - extends battery life in portable medical or handheld industrial devices between key interactions. |
Applications
| Medical Instrument Panels | Industrial Control Interfaces |
|---|---|
|
Use Scenario: Front-panel keypad on infusion pump or diagnostic analyzer requiring EMI-safe operation near sensitive analog signal paths. IC Role / Device Role / Timing Role: Dedicated key-scan peripheral managing 24 tactile buttons with hardware debounce and FIFO buffering - offloads microcontroller and eliminates scan-clock interference. Use Value: Enables certified Class B EMC compliance without added filtering or layout separation; reduces firmware complexity by 30% versus software-based debounce. |
Use Scenario: Operator interface on PLC-mounted HMI module deployed in factory-floor enclosures with wide temperature swings. IC Role / Device Role / Timing Role: Cold-temperature-qualified (–40°C) key controller providing deterministic 9–40ms debounce and interrupt-driven event reporting over I²C. Use Value: Guarantees reliable key registration at extreme ambient temperatures where capacitive touch fails; supports legacy 2.5V/3.3V backplane voltage. |
| Security Keypads | Test & Measurement Equipment |
|
Use Scenario: Tamper-resistant access keypad for biometric door controllers where false triggers from EMI or vibration must be eliminated. IC Role / Device Role / Timing Role: Static matrix monitor with 1kΩ switch tolerance and hardware-level debounce - rejects mechanical bounce and conducted noise simultaneously. Use Value: Achieves >99.99% key recognition accuracy in electrically noisy security vaults; removes need for redundant firmware validation. |
Use Scenario: Benchtop oscilloscope or spectrum analyzer with membrane keypad requiring silent, jitter-free button response. IC Role / Device Role / Timing Role: Low-noise key controller delivering synchronized interrupt pulses to main CPU - avoids timing skew in real-time measurement workflows. Use Value: Ensures sub-millisecond key-to-action latency with zero missed presses during rapid parameter adjustments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar key-switch controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX7348AEP+ | Supports 40 keys (5×8 matrix), 20-pin QSOP, adds tone generator and three GPOs; shares same I²C protocol and register map. | Required when >24 keys or audible feedback (key-click/alarm) is needed; not drop-in due to pin count and sounder functionality. | Select MAX7348AEP+ if expanding to 40-key panels or adding piezo feedback - verify PCB layout change for 20-pin footprint and SOUNDER routing. |
| TCA9554PWR | 8-bit I²C GPIO expander (no key-scan logic, no debounce, no FIFO); 16-pin TSSOP; 1.65–5.5V supply; no temperature rating beyond –40°C to +85°C. | Suitable only for simple switch polling with host-side debounce; lacks EMI-optimized static scan and interrupt-on-event capability. | Choose TCA9554PWR only for cost-sensitive, low-channel-count designs where firmware handles all timing - avoid for medical/industrial EMI-critical use. |
Compared with MAX7347AEE, MAX7348AEP+ adds scalability and audio feedback but requires board redesign, while TCA9554PWR sacrifices EMI resilience and hardware event management for basic I/O expansion - MAX7347AEE remains optimal for compact, certified, low-EMI 24-key systems.
Availability
MAX7347AEE is available at Aetrix Electronics and suitable for medical instrument panels, industrial control interfaces, and security keypads requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX7347AEE 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 MAX7347AEE belongs to Maxim's low-EMI key-switch controller product line, engineered specifically for EMI-sensitive human-interface applications where static matrix scanning and deterministic interrupt behavior are mandatory.
FAQ
What is the I²C slave address of the MAX7347AEE?
The MAX7347AEE uses a fixed 7-bit I²C slave address of 0x71 (1110001b) for its key-scan controller. Unlike MAX7348/MAX7349, it has no AD0 pin and no configurable address options. The MAX7347AEE does not implement a sounder controller, so no second slave address exists. This fixed addressing simplifies bus arbitration but limits multi-device configurations on the same I²C bus.
Does the MAX7347AEE support tone generation or sounder output?
No, the MAX7347AEE does not include tone generation or sounder output functionality. Per Maxim's datasheet, sounder features (including SOUNDER pin, musical frequencies, and dual-tone alarms) are exclusive to MAX7348 and MAX7349 variants. The MAX7347AEE pinout omits the SOUNDER terminal entirely, and its register map contains no sounder-related configuration registers - it is strictly a key-scan controller.
Can the INT pin on the MAX7347AEE be used as a general-purpose output (GPO)?
No, the INT pin on the MAX7347AEE is hardwired as an active-low interrupt output and cannot be reconfigured as a GPO. While MAX7348/MAX7349 allow INT to function as a GPO when sounder or alert features are disabled, the MAX7347AEE's configuration register (address 0x03) offers no such option - bit 7 is reserved and reads back as '0'. The device provides only one open-drain output: COL2/PORT2, which remains dedicated to column driving.
What is the maximum switch resistance supported by the MAX7347AEE?
The MAX7347AEE supports key switches with contact resistance up to 1kΩ, as specified in the "Key-Switch Resistance" parameter (RKEY = 1kΩ) under Electrical Characteristics. This applies to both metallic and carbon-film (resistive) switches. Exceeding 1kΩ may cause unreliable detection due to insufficient source current (28–40µA typical) and voltage margin (VKEY = 0.35–0.65V) at the switch node.
How many rows and columns does the MAX7347AEE support in its key matrix?
The MAX7347AEE supports an 8-row × 3-column matrix (24 keys total), using dedicated ROW0–ROW7 pins (8 inputs) and COL0, COL1, and COL2/PORT2 pins (3 outputs). This configuration is fixed and non-reconfigurable - there are no additional column/row pins or multiplexing options. Expanding beyond 24 keys requires upgrading to MAX7348 (40 keys) or MAX7349 (64 keys).
MAX7347AEE Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Applications:
- Sound Cards, Players, Recorders
- Interface:
- I2C
- Voltage - Supply:
- 2.4V ~ 3.6V
- Supplier Device Package:
- 16-QSOP
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
MAX7347AEE FAQ
1.How can I place an order for MAX7347AEE through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX7347AEE 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 MAX7347AEE reliable?
The price and inventory of MAX7347AEE are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX7347AEE is usually 5 days.
3.What payment methods are accepted for MAX7347AEE?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX7347AEE transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX7347AEE?
MAX7347AEE orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX7347AEE 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 MAX7347AEE?
For technical support, including MAX7347AEE datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX7347AEE requirements.
6.How does Aetrix verify that MAX7347AEE is sourced from the original manufacturer or authorized distributors?
All MAX7347AEE 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 MAX7347AEE meets industry standards.
7.What is the process for return or replacement of MAX7347AEE?
All MAX7347AEE units undergo pre-shipment inspection (PSI). If there is an issue with MAX7347AEE, 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 MAX7347AEE part is unused and in its original packaging.
Return procedure for MAX7347AEE:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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