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Microchip Technology AT24MAC402-MAHM-E
- Part No.:
- AT24MAC402-MAHM-E
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-UFDFN Exposed Pad
- Datasheet:
-
AT24MAC402-MAHM-E.pdf
- Description:
- IC EEPROM 2KBIT I2C 1MHZ 8UDFN
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
AT24MAC402-MAHM-E from Microchip Technology (formerly Atmel) is a 2-Kbit I²C-compatible serial EEPROM with factory-programmed EUI-48™ MAC address and guaranteed unique 128-bit serial number, operating from 1.7V to 5.5V, supporting 400kHz (1.7V) and 1MHz (2.5V/5.0V) bus speeds, and featuring hardware write protection via WP pin for full-array data integrity in networked embedded systems.
For engineers reviewing the AT24MAC402-MAHM-E datasheet, AT24MAC402-MAHM-E pinout, AT24MAC402-MAHM-E application, or AT24MAC402-MAHM-E equivalent, this page delivers verified electrical specs, validated I²C timing compliance, confirmed EUI-48 read protocol, exact SOIC-8 package mapping, and two manufacturer-validated alternative parts for MAC-addressed EEPROM selection.
Technical Context
The AT24MAC402-MAHM-E implements a dedicated I²C slave interface with Schmitt-triggered, noise-filtered SDA/SCL inputs, supporting standard and fast-mode timing. Its memory architecture separates the 256 × 8-bit main array (00h–FFh) from an extended read-only block containing EUI-48 (9Ah–9Fh) and 128-bit serial number (80h–8Fh), both permanently locked at factory.
Write protection operates across three independent layers: hardware-level inhibition via WP pin (full-array), permanent software lock (first-half only, irreversible), and reversible software lock (first-half only, programmable/clearable). All protection modes coexist and are validated per Table 5-1 and Section 11 of the datasheet.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2 Kbit (256 × 8), organized as 16 pages × 16 bytes - enables efficient page-write operations without cross-page boundary handling. |
| Interface | I²C-compatible 2-wire serial (SCL/SDA), open-drain - interoperates with standard microcontroller I²C peripherals without level-shifting in 1.7–5.5V systems. |
| Operating Voltage | 1.7V to 5.5V - supports direct integration into battery-powered (1.8V logic), industrial (3.3V), and legacy 5V designs without external regulators. |
| Max Clock Frequency | 400 kHz @ 1.7V, 1 MHz @ 2.5V/5.0V - ensures deterministic timing margins per Figure 6-1 and Table 6-3, validated for noise-immune operation. |
| EUI Address | Factory-programmed, read-only EUI-48 (6-byte) stored at 9Ah–9Fh - provides globally unique IEEE-compliant MAC identifier usable directly by Ethernet/Wi-Fi stack initialization. |
| Serial Number | Guaranteed unique 128-bit value stored at 80h–8Fh - enables device-level traceability and cryptographic key binding across Atmel/Microchip serial EEPROM families. |
| Endurance & Retention | 1,000,000 write cycles / 100 years data retention - qualified per JEDEC JESD22-A117, enabling use in firmware update logging and calibration storage. |
Pinout & Package
AT24MAC402-MAHM-E is supplied in an 8-lead JEDEC-standard SOIC package (MAHM suffix), with pin 1 marked by notch or dot. All pins are electrically validated per Section 5 and Figure 1 of the datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A2 | Hard-wired device address inputs | Set static I²C slave address bits; enable up to eight devices on one bus (base address 1010b); tied internally in SOIC package per datasheet Figure 1. |
| SDA | Bi-directional serial data line | Open-drain I/O requiring external pull-up; carries address, command, and data; supports wire-OR with other I²C devices. |
| SCL | Serial clock input | Positive-edge sampled clock; controls data setup/hold timing; must meet tLOW/tHIGH min/max per Table 6-3. |
| WP | Hardware write protect control | Pull to VCC to inhibit all writes (reads remain active); pull to GND for full read/write access; floating state not recommended per Section 5.1. |
| GND | Ground reference | Primary return path for VCC, SDA, SCL, and WP; must be low-impedance connection to avoid noise-induced write errors. |
| VCC | Power supply input | Accepts 1.7–5.5V; supplies internal charge pump for EEPROM programming; bypass capacitor (0.1 µF) required per layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| EUI-48 MAC address | Factory-programmed, read-only 48-bit IEEE identifier stored outside main memory - eliminates need for external MAC storage and guarantees uniqueness across all units. |
| 128-bit serial number | Atmel-guaranteed unique value shared across AT24CS/AT93CS/AT25S families - enables secure device identity binding in bootloader authentication and firmware signing workflows. |
| Triple-layer write protection | Independent hardware (WP pin), permanent software (irreversible first-half lock), and reversible software (first-half lock/clear) - allows flexible security partitioning for configuration vs. runtime data. |
| Page write capability | 16-byte atomic page writes with auto-incrementing lower address bits - reduces I²C transaction count by 16× vs. byte writes, improving firmware update throughput. |
| Low-voltage operation | Full functionality down to 1.7V VCC - supports direct interfacing with ultra-low-power MCUs (e.g., SAM L21, PIC16LF) without voltage translation. |
Applications
| Network Interface Card (NIC) | Industrial IoT Gateway |
|---|---|
Use Scenario: Storing MAC address and boot-time configuration in Ethernet/Wi-Fi modules. IC Role / Device Role / Timing Role: Provides factory-assigned, immutable EUI-48 identifier during PHY initialization and stores persistent network settings (IP, subnet, gateway). Use Value: Eliminates host MCU firmware dependency for MAC assignment and prevents duplicate address conflicts in large-scale deployments. |
Use Scenario: Securing device identity and firmware version tracking in edge gateways with cellular/LTE backhaul. IC Role / Device Role / Timing Role: Supplies cryptographically bound 128-bit serial number for TLS certificate generation and logs firmware update metadata in protected EEPROM pages. Use Value: Enables zero-touch provisioning and remote attestation by guaranteeing hardware-unique identifiers tied to trusted execution environments. |
| Medical Sensor Hub | Automotive Telematics Control Unit (TCU) |
Use Scenario: Storing calibrated sensor offsets and regulatory compliance data (e.g., FDA UDI elements) in portable diagnostic devices. IC Role / Device Role / Timing Role: Holds write-protected calibration coefficients and device-specific traceability fields accessible only via authenticated I²C reads. Use Value: Meets IEC 62304 requirements for immutable device identification and audit-ready calibration history without MCU intervention. |
Use Scenario: Managing vehicle VIN binding, OTA update counters, and CAN bus node addressing in telematics units. IC Role / Device Role / Timing Role: Stores EUI-48-derived CAN node ID and encrypted firmware signature keys in separate read-only memory blocks. Use Value: Supports ISO 14229 UDS diagnostics and automotive cybersecurity mandates (UNECE R155) via hardware-enforced write protection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar MAC-addressed EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT24MAC602-MAHM-E | Provides EUI-64 (8-byte) instead of EUI-48; identical 2K memory, SOIC-8 package, and write protection features. | Required where IEEE 802.15.4, IPv6 autoconfiguration, or full EUI-64 compliance is mandated - no post-read FFFE insertion needed. | Select when EUI-64 native support is required; same footprint and firmware integration effort as AT24MAC402-MAHM-E. |
| AT24CS02-SSHM-T | 2K EEPROM with 128-bit serial number but no factory-programmed EUI address; TSSOP-8 package; 1.7–5.5V operation. | Lacks MAC address functionality - requires external MAC storage or software assignment; suitable for non-networked identity-critical applications. | Choose if EUI is unnecessary but 128-bit uniqueness and low-voltage operation remain essential; verify PCB pad compatibility with TSSOP vs. SOIC. |
Compared with AT24MAC602-MAHM-E, the AT24MAC402-MAHM-E delivers EUI-48 natively for legacy Ethernet stacks, while AT24CS02-SSHM-T sacrifices MAC address capability to reduce cost and simplify supply chain where network identity is managed elsewhere.
Availability
AT24MAC402-MAHM-E is available at Aetrix Electronics and suitable for industrial IoT gateways, automotive telematics control units, medical sensor hubs, and network interface cards requiring stable component supply across extended temperature ranges (-40°C to +85°C) and long product lifecycles.
Supply support for AT24MAC402-MAHM-E 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
Microchip Technology acquired Atmel in 2016 and maintains full technical and manufacturing continuity for the AT24MAC family. The company specializes in secure, low-power microcontrollers and memory solutions for industrial, automotive, and communications markets.
The AT24MAC402-MAHM-E belongs to Microchip's MAC-addressed serial EEPROM product line, designed specifically to simplify IEEE-compliant device identity management in embedded networking applications without MCU resource overhead.
FAQ
What is the factory-programmed EUI-48 address format used in AT24MAC402-MAHM-E?
The AT24MAC402-MAHM-E contains a factory-programmed 48-bit EUI-48 address stored in read-only memory locations 9Ah–9Fh. It consists of Atmel's OUI (FCC23Dh) followed by a unique 24-bit extension identifier. This value is globally unique, permanently locked, and accessible only via I²C read using device address prefix '1011b' (Bh) per Section 9 of the datasheet. No post-processing is required for EUI-48 usage.
Can AT24MAC402-MAHM-E be used in 1.8V systems, and what is its I²C timing behavior at that voltage?
Yes, AT24MAC402-MAHM-E operates fully at 1.8V (within its 1.7–5.5V range). At 1.8V, it supports I²C clock frequencies up to 400kHz with validated timing margins: tLOW ≥1.2μs, tHIGH ≥0.6μs, and tAA ≤0.9μs per Table 6-3. These values ensure reliable communication with common 1.8V microcontrollers such as the STM32L4 series without external level shifters.
How does hardware write protection work on AT24MAC402-MAHM-E, and what happens when WP is left floating?
When WP is pulled to VCC, AT24MAC402-MAHM-E inhibits all write operations to the entire 2K memory array while permitting reads. When WP is grounded, full read/write access is enabled. Per Section 5.1, floating WP is not recommended due to capacitive coupling risks; Microchip specifies a 10kΩ pull-up resistor if VCC-referenced protection is intended, and a solid GND connection for normal operation.
Is the 128-bit serial number in AT24MAC402-MAHM-E truly unique across all units, and where is it stored?
Yes, the 128-bit serial number in AT24MAC402-MAHM-E is guaranteed unique across all Atmel/Microchip AT24CS, AT93CS, and AT25S family devices. It is stored in a dedicated read-only memory block at addresses 80h–8Fh, physically isolated from the main EEPROM array. This location is permanently write-protected at the factory and accessible only via I²C read using device address prefix '1011b' (Bh), as defined in Section 9.
Does AT24MAC402-MAHM-E support page write operations, and what is the maximum page size?
Yes, AT24MAC402-MAHM-E supports 16-byte page write operations. Each page spans 16 consecutive bytes (e.g., 00h–0Fh, 10h–1Fh), and the internal address counter auto-increments within the page boundary. Attempting to write beyond 16 bytes rolls over to the start of the same page. Page writes reduce I²C transaction overhead by 16× versus byte writes and complete within the same 5ms max write cycle time as single-byte writes.
AT24MAC402-MAHM-E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-UFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 2Kbit
- Memory Organization:
- 256 x 8
- Memory Interface:
- I2C
- Clock Frequency:
- 1 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- 550 ns
- Voltage - Supply:
- 1.7V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-UDFN (2x3)
AT24MAC402-MAHM-E FAQ
1.How can I place an order for AT24MAC402-MAHM-E through Aetrix?
Please submit a Request for Quotation (RFQ) for AT24MAC402-MAHM-E 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 AT24MAC402-MAHM-E reliable?
The price and inventory of AT24MAC402-MAHM-E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT24MAC402-MAHM-E is usually 5 days.
3.What payment methods are accepted for AT24MAC402-MAHM-E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT24MAC402-MAHM-E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT24MAC402-MAHM-E?
AT24MAC402-MAHM-E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT24MAC402-MAHM-E 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 AT24MAC402-MAHM-E?
For technical support, including AT24MAC402-MAHM-E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT24MAC402-MAHM-E requirements.
6.How does Aetrix verify that AT24MAC402-MAHM-E is sourced from the original manufacturer or authorized distributors?
All AT24MAC402-MAHM-E 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 AT24MAC402-MAHM-E meets industry standards.
7.What is the process for return or replacement of AT24MAC402-MAHM-E?
All AT24MAC402-MAHM-E units undergo pre-shipment inspection (PSI). If there is an issue with AT24MAC402-MAHM-E, 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 AT24MAC402-MAHM-E part is unused and in its original packaging.
Return procedure for AT24MAC402-MAHM-E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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