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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Microchip Technology AT34C02D-MAHM-T

Name: AT34C02D-MAHM-T
Brand: Microchip Technology
SKU: AT34C02D-MAHM-T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AT34C02D-MAHM-T

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-UFDFN Exposed Pad

Datasheet:: AT34C02D-MAHM-T.pdf

Description:: IC EEPROM 2KBIT I2C 1MHZ 8UDFN

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Product details

Overview

AT34C02D-MAHM-T from Microchip Technology (formerly Atmel) is a JEDEC EE1002/EE1002A-compliant Serial Presence Detect (SPD) EEPROM for DDR/DDR2/DDR3 DIMM modules, providing 2,048-bit (256 × 8) I²C-compatible nonvolatile memory with 1.7V–5.5V operation, permanent/reversible software write protection for lower 128 bytes, and hardware write protection via WP pin.

For engineers reviewing the AT34C02D-MAHM-T datasheet, AT34C02D-MAHM-T pinout, AT34C02D-MAHM-T application, or AT34C02D-MAHM-T equivalent, this page delivers verified electrical specs, SPD-specific timing compliance, dual-layer write protection behavior, UDFN-8 package details, and real-world DIMM module integration context - all grounded in the official Atmel-8781D datasheet.

Technical Context

The AT34C02D-MAHM-T implements an I²C-compatible 2-wire interface with 400 kHz max speed at 1.7V/2.5V and 1 MHz at 5.0V, supporting standard and fast-mode protocols. Its internal architecture includes a 16-page × 16-byte memory array, addressable via 8-bit word addresses, with Schmitt-triggered SCL/SDA inputs for noise immunity in high-density memory subsystems.

Write protection is implemented through three independent mechanisms: hardware-level inhibition via WP pin (VCC = full-array lock), permanent software lock of addresses 0x00–0x7F (irreversible once set), and reversible software lock of the same region (enabled/disabled via dedicated command sequences using A2/A1/A0 and VHV voltage). All protections coexist and are evaluated hierarchically during write attempts.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	2,048 bits (256 × 8), organized as 16 pages × 16 bytes - enables byte/page writes without external address latching.
Supply Voltage	1.7V to 5.5V - supports direct interfacing with DDR DIMM VDDQ rails (1.2V–1.5V via level-shifting) and legacy 3.3V/5V systems.
I²C Speed	400 kHz @ 1.7V/2.5V; 1 MHz @ 5.0V - meets JEDEC SPD timing requirements for DDR2/DDR3 initialization handshakes.
Write Cycle Time	≤5 ms - deterministic self-timed erase/write ensures predictable boot-time SPD data loading without polling overhead.
Endurance & Retention	1,000,000 write cycles; 100-year data retention - qualified for lifetime use in unattended server and telecom memory modules.
Operating Temp	−40°C to +85°C (Industrial grade) - validated for sustained operation inside memory module PCBs under thermal stress.
Package	8-pad 2.0 mm × 3.0 mm UDFN (8MA2), 0.6 mm body height - ultra-low-profile footprint ideal for space-constrained DIMM edge mounting.

Pinout & Package

AT34C02D-MAHM-T uses the 8-pad 2.0 mm × 3.0 mm Ultra Thin Dual Flat No-Lead (UDFN) package (drawing 8MA2), with exposed thermal pad and laser-marked Pin 1 identifier on top surface. Pin 1 is located at bottom-left corner when notch or marking is oriented top-left.

Pin/Terminal	Circuit Role	Design Meaning
A0–A2	Hardware device address inputs	Hardwired to GND/VCC to select one of eight possible I²C addresses (1010xxxR/W); floating defaults to GND but requires explicit biasing per JEDEC SPD layout guidelines.
GND	Ground reference	Primary return path for VCC and I/O; connects to thermal pad for improved heat dissipation in high-density DIMM layouts.
SDA	Serial Data bidirectional line	Open-drain I²C bus node requiring external pull-up; supports wire-OR with other SPD EEPROMs on same DIMM channel.
SCL	Serial Clock input	Positive-edge clock for data-in, negative-edge for data-out; Schmitt-triggered to reject noise from adjacent memory traces.
WP	Hardware write protect control	Pulled to VCC to disable all writes (full-array lock); pulled to GND or left floating to enable software-controlled protection modes.
VCC	Power supply input	Accepts 1.7V–5.5V; internal regulation enables stable EEPROM operation across DDR VDDQ voltage tolerances.

Key Features

Feature	Design Value
JEDEC EE1002/EE1002A SPD Compliance	Fully satisfies DDR/DDR2/DDR3 DIMM serial presence detect specification - guaranteed interoperability with memory controller SPD parsers.
Dual Software Write Protection	Separate permanent (one-time) and reversible (toggleable) locks for lower 128 bytes - enables secure storage of critical DIMM timing parameters while allowing field-updatable vendor data.
Hardware WP Pin Lock	Physical write inhibit independent of software state - prevents accidental or malicious overwrites during system boot or firmware updates.
16-byte Page Write Mode	Enables burst programming of SPD data blocks (e.g., JEDEC parameter tables) in ≤5 ms, reducing DIMM initialization latency vs. byte-by-byte writes.
Low-Power Standby	1.0 μA max standby current at 1.7V - minimizes parasitic drain on DIMM VDDQ rail during system sleep states.

Applications

DDR3 Server Memory Modules	DDR4 RDIMM SPD Storage
Use Scenario: Storing JEDEC-defined timing parameters, manufacturer ID, module capacity, and thermal sensor calibration data on registered DIMMs used in enterprise servers. IC Role / Device Role / Timing Role: SPD EEPROM providing standardized I²C-accessible configuration data read by memory controller during power-on initialization sequence. Use Value: Enables plug-and-play compatibility across vendors; AT34C02D-MAHM-T's 1.7V–5.5V range accommodates DDR3 VDDQ (1.5V ±0.075V) with margin, and its 100-year retention ensures data integrity over multi-year server deployments.	Use Scenario: Holding SPD data for load-reduced DIMMs (LRDIMMs) where multiple ranks require consolidated SPD access via I²C multiplexing. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed early in boot process to configure memory controller register settings before DRAM training. Use Value: AT34C02D-MAHM-T's 400 kHz I²C speed and Schmitt-triggered inputs ensure reliable communication in electrically noisy LRDIMM routing environments; UDFN-8 package saves board area near edge connectors.
Industrial Embedded SODIMMs	Automotive ADAS Memory Subsystems
Use Scenario: Providing SPD data for ruggedized SODIMMs deployed in factory automation controllers operating in −40°C to +85°C ambient conditions. IC Role / Device Role / Timing Role: Industrial-grade SPD EEPROM ensuring consistent memory initialization across temperature extremes and long-term storage without data corruption. Use Value: AT34C02D-MAHM-T's industrial temp rating, 1M-cycle endurance, and hardware WP pin allow safe field updates of module parameters while preventing inadvertent writes during vibration-induced signal coupling.	Use Scenario: Storing calibrated memory timing offsets and safety-critical configuration flags in automotive ADAS domain controllers using DDR4 memory interfaces. IC Role / Device Role / Timing Role: Safety-aware SPD storage with dual software/hardware write protection to prevent unauthorized modification of memory timing parameters affecting functional safety compliance. Use Value: Permanent software lock secures immutable calibration data; reversible lock allows authorized firmware updates to vendor-specific fields - both enforced regardless of WP pin state once enabled.

DDR3 Server Memory Modules

DDR4 RDIMM SPD Storage

Use Scenario: Storing JEDEC-defined timing parameters, manufacturer ID, module capacity, and thermal sensor calibration data on registered DIMMs used in enterprise servers.

IC Role / Device Role / Timing Role: SPD EEPROM providing standardized I²C-accessible configuration data read by memory controller during power-on initialization sequence.

Use Value: Enables plug-and-play compatibility across vendors; AT34C02D-MAHM-T's 1.7V–5.5V range accommodates DDR3 VDDQ (1.5V ±0.075V) with margin, and its 100-year retention ensures data integrity over multi-year server deployments.

Use Scenario: Holding SPD data for load-reduced DIMMs (LRDIMMs) where multiple ranks require consolidated SPD access via I²C multiplexing.

IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed early in boot process to configure memory controller register settings before DRAM training.

Use Value: AT34C02D-MAHM-T's 400 kHz I²C speed and Schmitt-triggered inputs ensure reliable communication in electrically noisy LRDIMM routing environments; UDFN-8 package saves board area near edge connectors.

Industrial Embedded SODIMMs

Automotive ADAS Memory Subsystems

Use Scenario: Providing SPD data for ruggedized SODIMMs deployed in factory automation controllers operating in −40°C to +85°C ambient conditions.

IC Role / Device Role / Timing Role: Industrial-grade SPD EEPROM ensuring consistent memory initialization across temperature extremes and long-term storage without data corruption.

Use Value: AT34C02D-MAHM-T's industrial temp rating, 1M-cycle endurance, and hardware WP pin allow safe field updates of module parameters while preventing inadvertent writes during vibration-induced signal coupling.

Use Scenario: Storing calibrated memory timing offsets and safety-critical configuration flags in automotive ADAS domain controllers using DDR4 memory interfaces.

IC Role / Device Role / Timing Role: Safety-aware SPD storage with dual software/hardware write protection to prevent unauthorized modification of memory timing parameters affecting functional safety compliance.

Use Value: Permanent software lock secures immutable calibration data; reversible lock allows authorized firmware updates to vendor-specific fields - both enforced regardless of WP pin state once enabled.

Equivalent & Alternatives

The following parts are listed as comparable options for similar SPD EEPROM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STMicroelectronics M24C02-RMN6TP	2-Kbit I²C EEPROM, 1.7V–5.5V, SO8 package only; no permanent software write protection; hardware WP pin present.	Lacks irreversible lower-half lock - unsuitable where JEDEC SPD mandates tamper-proof storage of base timing parameters.	Select when full-array hardware WP suffices and SOIC footprint is acceptable; verify SPD timing compliance per JEDEC spec.
ON Semiconductor CAT24C02HU4IGT3	2-Kbit I²C EEPROM, 1.7V–5.5V, UDFN-8 package; software write protection limited to entire array (no lower-half granularity); no permanent lock mode.	Supports only global software lock - cannot meet JEDEC EE1002A requirement for independent protection of SPD base vs. extended data regions.	Choose for cost-sensitive industrial DIMMs where SPD data is static and full-array lock is sufficient; confirm AC timing matches DDR2/DDR3 startup windows.

Compared with M24C02-RMN6TP and CAT24C02HU4IGT3, the AT34C02D-MAHM-T uniquely delivers JEDEC-mandated dual-layer (permanent + reversible) lower-half write protection in a space-saving UDFN package - essential for secure, standards-compliant SPD implementation in modern memory modules.

Availability

AT34C02D-MAHM-T is available at Aetrix Electronics and suitable for DDR3 server memory modules, industrial SODIMMs, automotive ADAS memory subsystems, and embedded computing platforms requiring stable component supply, long-lifecycle support, and JEDEC SPD compliance.

Supply support for AT34C02D-MAHM-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

Microchip Technology acquired Atmel in 2016 and maintains full product continuity, quality assurance, and technical documentation for the AT34C02D family. Microchip is a global leader in microcontrollers, analog, and memory solutions.

The AT34C02D series was designed specifically for JEDEC Serial Presence Detect applications in DDR/DDR2/DDR3 memory modules, delivering robust, low-voltage, standards-compliant nonvolatile storage in miniature packages optimized for DIMM edge mounting.

FAQ

What is the primary function of the AT34C02D-MAHM-T in memory modules?

The AT34C02D-MAHM-T serves as a JEDEC EE1002/EE1002A-compliant Serial Presence Detect (SPD) EEPROM, storing critical configuration data - including timing parameters, module capacity, manufacturer ID, and thermal calibration - for DDR/DDR2/DDR3 DIMMs. It is read by the memory controller during system boot to initialize DRAM correctly. Its 2-Kbit capacity, I²C interface, and industrial temperature rating make it purpose-built for this role in server, industrial, and automotive memory applications.

Does the AT34C02D-MAHM-T support both permanent and reversible write protection?

Yes, the AT34C02D-MAHM-T implements two distinct software write protection modes for the lower 128 bytes (addresses 0x00–0x7F): a permanent lock that, once enabled, cannot be reversed even after power cycling; and a reversible lock that can be toggled on/off using specific command sequences with controlled A2/A1/A0 and VHV voltage conditions. Both operate independently of the hardware WP pin, enabling layered security for SPD data integrity.

What package type does the AT34C02D-MAHM-T use, and why is it suitable for DIMMs?

The AT34C02D-MAHM-T uses an 8-pad 2.0 mm × 3.0 mm Ultra Thin Dual Flat No-Lead (UDFN) package (drawing 8MA2), with 0.6 mm body height and exposed thermal pad. This ultra-compact, low-profile package is ideal for edge-mounting on DDR DIMMs where board space is severely constrained - especially near gold-finger connectors - while maintaining thermal performance and mechanical robustness under vibration and thermal cycling.

How does the WP pin affect write operations on the AT34C02D-MAHM-T?

When the WP pin is connected to VCC, all write operations to the AT34C02D-MAHM-T memory array are inhibited - regardless of software write protection status. When WP is GND or floating, software-based protection (permanent or reversible) governs write access to the lower 128 bytes, while the upper 128 bytes remain freely writable. The WP pin thus provides a physical, hardware-enforced override that supersedes all software controls.

Is the AT34C02D-MAHM-T compatible with DDR4 memory modules?

The AT34C02D-MAHM-T is explicitly designed for JEDEC EE1002 and EE1002A compliance, which cover DDR, DDR2, and DDR3 DIMMs. While its electrical interface (I²C, 1.7V–5.5V, 400 kHz/1 MHz) is technically compatible with DDR4 SPD requirements, DDR4 uses the updated JEDEC JESD21-C specification and typically requires higher-density EEPROMs (e.g., 4-Kbit). Therefore, AT34C02D-MAHM-T is not recommended for new DDR4 designs unless validated per JESD21-C and confirmed by the memory controller vendor.

AT34C02D-MAHM-T 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:: -

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)

AT34C02D-MAHM-T FAQ

1.How can I place an order for AT34C02D-MAHM-T through Aetrix?

Please submit a Request for Quotation (RFQ) for AT34C02D-MAHM-T 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 AT34C02D-MAHM-T reliable?

The price and inventory of AT34C02D-MAHM-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT34C02D-MAHM-T is usually 5 days.

3.What payment methods are accepted for AT34C02D-MAHM-T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT34C02D-MAHM-T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AT34C02D-MAHM-T?

AT34C02D-MAHM-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AT34C02D-MAHM-T 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 AT34C02D-MAHM-T?

For technical support, including AT34C02D-MAHM-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT34C02D-MAHM-T requirements.

6.How does Aetrix verify that AT34C02D-MAHM-T is sourced from the original manufacturer or authorized distributors?

All AT34C02D-MAHM-T 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 AT34C02D-MAHM-T meets industry standards.

7.What is the process for return or replacement of AT34C02D-MAHM-T?

All AT34C02D-MAHM-T units undergo pre-shipment inspection (PSI). If there is an issue with AT34C02D-MAHM-T, 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 AT34C02D-MAHM-T part is unused and in its original packaging.

Return procedure for AT34C02D-MAHM-T:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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