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

Microchip Technology AT34C02D-MAHM-E

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

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Part No.:: AT34C02D-MAHM-E

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-UFDFN Exposed Pad

Datasheet:: AT34C02D-MAHM-E.pdf

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

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Product details

Overview

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

For engineers reviewing the AT34C02D-MAHM-E datasheet, AT34C02D-MAHM-E pinout, AT34C02D-MAHM-E application, or AT34C02D-MAHM-E equivalent, this device supports SPD-critical memory configuration storage in high-reliability server, workstation, and industrial memory subsystems where voltage flexibility, 100-year data retention, and multi-layer write protection are required.

Technical Context

The AT34C02D-MAHM-E implements an I²C-compatible 2-wire interface with 400 kHz support at 1.7V/2.5V and 1 MHz at 5.0V, using Schmitt-trigger filtered inputs for noise immunity. Its internal architecture includes a 16-page × 16-byte memory array with auto-incrementing address counters for sequential reads and page-write capability.

Write protection is implemented through three independent mechanisms: hardware-level inhibition via the WP pin (full-array lock when tied to V_CC), irreversible software locking of addresses 0x00–0x7F, and reversible software locking of the same region using dedicated command sequences (0x62h/0x66h) with specific A2/A1/A0 and V_HV conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	2,048 bits (256 × 8), organized as 16 pages of 16 bytes - enables compact SPD data storage for DDR/DDR2/DDR3 module identification and timing parameters.
Supply Voltage	1.7V to 5.5V - supports interoperability across legacy 3.3V and modern low-voltage 1.8V/1.7V DIMM power domains without level-shifting.
I²C Speed	400 kHz @ 1.7V/2.5V; 1 MHz @ 5.0V - ensures fast SPD initialization during system boot while maintaining robustness at reduced voltages.
Write Endurance	1,000,000 cycles - guarantees reliable field updates of SPD data across decades of server maintenance cycles and firmware revisions.
Data Retention	100 years @ 25°C - meets long-term archival requirements for memory module lifetime tracking and calibration persistence.
Write Cycle Time	≤5 ms - defines minimum inter-write interval for SPD configuration writes; compatible with standard SMBus timeout budgets.
Operating Temp	−40°C to +85°C - qualified for industrial-grade DIMM operation in extended-temperature servers, telecom, and embedded systems.

Pinout & Package

AT34C02D-MAHM-E uses an 8-pad 2.0 mm × 3.0 mm Ultra Thin Dual Flat No-Lead (UDFN) package (JEDEC MO-229 compliant, body height 0.55 mm max), optimized for space-constrained DIMM PCB layouts and thermal performance in memory modules.

Pin/Terminal	Circuit Role	Design Meaning
A0–A2	Hardware Device Address Inputs	Enable up to eight AT34C02D devices on one I²C bus; must be hardwired to GND/V_CC - floating pins default to GND but risk coupling-induced misaddressing.
GND	Ground Reference	Primary return path for all digital and internal charge-pump circuits; requires low-impedance connection to DIMM ground plane.
SDA	Serial Data Bidirectional Line	Open-drain I²C data line; requires external pull-up (typically 2.2–10 kΩ) to V_CC; shared across multiple SPD devices on DIMM.
SCL	Serial Clock Input	Positive-edge clock input for data latching; negative-edge sampling for data output; must meet t_LOW/t_HIGH timing per JEDEC SPD spec.
WP	Hardware Write Protect Control	Active-high (V_CC) disables all writes to full array; GND/floating enables software-controlled protection modes - critical for preventing accidental SPD corruption.
V_CC	Power Supply Input	Single-supply input supporting 1.7–5.5V; powers internal HV pump for EEPROM programming; bypass capacitor (100 nF) recommended near pad.

Key Features

Feature	Design Value
JEDEC EE1002/EE1002A SPD Compliance	Fully satisfies DDR/DDR2/DDR3 DIMM Serial Presence Detect specification - ensures plug-and-play compatibility with host memory controllers and BIOS SPD parsers.
Dual Software Write Protection	Permanent lock (irreversible, protects 0x00–0x7F) + reversible lock (programmable via 0x62h/0x66h commands) - enables secure factory-programmed base SPD data and field-updatable extended fields.
Hardware WP Pin	Full-array write disable when tied to V_CC - provides board-level physical security against runtime corruption during system operation or debug access.
16-Byte Page Write	Enables efficient bulk SPD updates (e.g., full timing table writes) with single-stop sequencing - reduces I²C transaction overhead vs. byte-by-byte writes.
Schmitt-Trigger Inputs	Filters noise on SDA/SCL lines in electrically noisy DIMM environments - prevents false start/stop detection and improves SPD read reliability during hot-plug events.

Applications

DDR3 Server DIMM SPD Storage	Industrial DDR2 Memory Module Calibration
Use Scenario: Storing JEDEC-defined SPD data (module type, density, timings, manufacturer ID) on enterprise-class DDR3 RDIMMs for BIOS initialization and memory training. IC Role / Device Role / Timing Role: Dedicated SPD EEPROM interfacing directly to SMBus controller; provides deterministic 256-byte configuration space with guaranteed read latency ≤10 μs. Use Value: Enables automatic memory configuration without manual BIOS setup; supports RAS features like patrol scrub and mirroring via persistent error-correction parameter storage.	Use Scenario: Maintaining temperature-compensated timing offsets and vendor-specific calibration coefficients in ruggedized DDR2 modules used in railway signaling and PLC backplanes. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed during cold boot and periodic recalibration; retains data across wide −40°C to +85°C operating range. Use Value: Eliminates need for external calibration EEPROM or microcontroller-based tuning - reduces BOM count and improves startup predictability in safety-critical systems.
DDR4-Compatible Legacy DIMM Adapter	Embedded Systems Memory Subsystem Diagnostics
Use Scenario: Backward-compatible SPD emulation in DDR4-to-DDR3 adapter modules, where AT34C02D-MAHM-E holds translated SPD data for legacy controller compatibility. IC Role / Device Role / Timing Role: SPD translator buffer; responds to standard I²C read requests with pre-mapped DDR3-equivalent values derived from DDR4 SPD structure. Use Value: Allows reuse of existing DDR3 memory controllers with newer DDR4 modules - extends platform lifecycle without hardware redesign.	Use Scenario: Logging memory test results (e.g., March C failures, ECC event counts) and storing diagnostic history in edge-computing gateways with limited flash endurance. IC Role / Device Role / Timing Role: Field-serviceable nonvolatile log storage; leverages 1M write cycles to outlast NAND-based logging in high-diagnostic-frequency deployments. Use Value: Provides tamper-resistant, low-power diagnostic persistence between reboots - supports root-cause analysis without requiring continuous DRAM refresh or battery-backed SRAM.

DDR3 Server DIMM SPD Storage

Industrial DDR2 Memory Module Calibration

Use Scenario: Storing JEDEC-defined SPD data (module type, density, timings, manufacturer ID) on enterprise-class DDR3 RDIMMs for BIOS initialization and memory training.

IC Role / Device Role / Timing Role: Dedicated SPD EEPROM interfacing directly to SMBus controller; provides deterministic 256-byte configuration space with guaranteed read latency ≤10 μs.

Use Value: Enables automatic memory configuration without manual BIOS setup; supports RAS features like patrol scrub and mirroring via persistent error-correction parameter storage.

Use Scenario: Maintaining temperature-compensated timing offsets and vendor-specific calibration coefficients in ruggedized DDR2 modules used in railway signaling and PLC backplanes.

IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed during cold boot and periodic recalibration; retains data across wide −40°C to +85°C operating range.

Use Value: Eliminates need for external calibration EEPROM or microcontroller-based tuning - reduces BOM count and improves startup predictability in safety-critical systems.

DDR4-Compatible Legacy DIMM Adapter

Embedded Systems Memory Subsystem Diagnostics

Use Scenario: Backward-compatible SPD emulation in DDR4-to-DDR3 adapter modules, where AT34C02D-MAHM-E holds translated SPD data for legacy controller compatibility.

IC Role / Device Role / Timing Role: SPD translator buffer; responds to standard I²C read requests with pre-mapped DDR3-equivalent values derived from DDR4 SPD structure.

Use Value: Allows reuse of existing DDR3 memory controllers with newer DDR4 modules - extends platform lifecycle without hardware redesign.

Use Scenario: Logging memory test results (e.g., March C failures, ECC event counts) and storing diagnostic history in edge-computing gateways with limited flash endurance.

IC Role / Device Role / Timing Role: Field-serviceable nonvolatile log storage; leverages 1M write cycles to outlast NAND-based logging in high-diagnostic-frequency deployments.

Use Value: Provides tamper-resistant, low-power diagnostic persistence between reboots - supports root-cause analysis without requiring continuous DRAM refresh or battery-backed SRAM.

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, 1.7–5.5V, 400 kHz, SO8 package only; no permanent software write protect; hardware WP only covers full array.	Lacks irreversible lower-half lock - unsuitable for factory-locked SPD base data requiring zero-field modification risk.	Select when full-array hardware WP suffices and UDFN footprint is not required; verify SPD timing compliance per JEDEC EE1002A Annex B.
ON Semiconductor CAT24C02HU4IGT3	2 Kbit I²C EEPROM, 1.7–5.5V, 1 MHz, 8-ball VFBGA (1.5×2.0 mm); includes software write protect (reversible only), no permanent mode.	Matches AT34C02D-MAHM-E's VFBGA option but omits permanent protection - limits use to applications where all SPD fields must remain field-updatable.	Prefer for space-constrained DIMMs needing VFBGA; confirm WP pin behavior aligns with host SPD initialization sequence before deployment.

Compared with M24C02-RMN6TP and CAT24C02HU4IGT3, the AT34C02D-MAHM-E uniquely delivers irreversible lower-half software write protection - essential for securing immutable JEDEC SPD base fields while allowing field updates to extended regions, all within a 2.0×3.0 mm UDFN footprint.

Availability

AT34C02D-MAHM-E is available at Aetrix Electronics and suitable for DDR3 server DIMMs, industrial DDR2 memory modules, DDR4-to-DDR3 adapter designs, and embedded diagnostic subsystems requiring stable component supply, long-lifecycle support, and JEDEC SPD compliance.

Supply support for AT34C02D-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 product continuity, qualification, and technical support for the AT34C02D family. The company specializes in secure, reliable microcontrollers and memory solutions for industrial and automotive markets.

The AT34C02D product line was designed specifically for Serial Presence Detect in DDR/DDR2/DDR3 memory modules, delivering JEDEC-compliant SPD functionality with enhanced write protection and wide-voltage operation for memory subsystem designers.

FAQ

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

The AT34C02D-MAHM-E serves as the JEDEC EE1002/EE1002A-compliant Serial Presence Detect (SPD) EEPROM in DDR/DDR2/DDR3 DIMMs. It stores critical module identification, timing, and configuration data readable by the host memory controller during system boot. Its 2 Kbit capacity (256 × 8) and I²C interface ensure compatibility with standard SMBus protocols used in server and industrial platforms. The AT34C02D-MAHM-E is specifically engineered to meet SPD timing and data integrity requirements defined in JEDEC specifications.

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

Yes, the AT34C02D-MAHM-E implements two distinct software write protection modes. Permanent protection locks addresses 0x00–0x7F irreversibly after programming - once enabled, it cannot be cleared even with power cycling. Reversible protection for the same address range can be enabled or disabled using dedicated command sequences (0x62h to set, 0x66h to clear) with specific A2/A1/A0 and V_HV conditions. Both modes operate independently of the hardware WP pin. This dual-layer scheme is integral to the AT34C02D-MAHM-E's SPD security architecture.

What package type does the AT34C02D-MAHM-E use, and what are its key mechanical dimensions?

The AT34C02D-MAHM-E uses an 8-pad Ultra Thin Dual Flat No-Lead (UDFN) package designated 8MA2, measuring 2.0 mm × 3.0 mm with a maximum body height of 0.60 mm. It complies with JEDEC MO-229 standards and features a thermal pad on the bottom for enhanced heat dissipation in dense DIMM layouts. Pin 1 is laser-marked on the top surface, and the package is lead-free/halogen-free with NiPdAu finish. This compact footprint is specified in the AT34C02D-MAHM-E ordering code and validated in Microchip's packaging documentation.

How does hardware write protection via the WP pin interact with software protection modes in the AT34C02D-MAHM-E?

In the AT34C02D-MAHM-E, tying the WP pin to V_CC disables all write operations to the entire memory array regardless of software protection status - it overrides both permanent and reversible software locks. When WP is grounded or floating, software protection modes determine write access to the lower 128 bytes (0x00–0x7F), while upper bytes remain freely writable. The WP pin state also governs whether software protection registers can be programmed: WP = V_CC blocks all register writes. This hierarchical control is explicitly defined in the AT34C02D-MAHM-E datasheet Tables 4-1 and 8-4.

What are the I²C timing specifications for the AT34C02D-MAHM-E at different supply voltages?

The AT34C02D-MAHM-E supports 400 kHz I²C operation at 1.7V and 2.5V supply, and 1 MHz operation at 5.0V. Key AC parameters include t_LOW ≥ 4,700 ns (1.7–3.6V), t_HIGH ≥ 4,000 ns (1.7–3.6V), and t_WR ≤ 5 ms for write cycles. Rise/fall times are characterized down to 100 ns at 5.5V. These values are measured under JEDEC-specified conditions and ensure compatibility with standard SMBus controllers used in DIMM SPD applications. All timing constraints apply directly to the AT34C02D-MAHM-E and are verified per Atmel-8781D datasheet Section 5.4.

AT34C02D-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:: -

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-E FAQ

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

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

The price and inventory of AT34C02D-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 AT34C02D-MAHM-E is usually 5 days.

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

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

Note: Certain payment methods may incur a processing fee.

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

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

Once your AT34C02D-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 AT34C02D-MAHM-E?

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

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

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

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

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

Return procedure for AT34C02D-MAHM-E:

1.Submit a request within 90 days.

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

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