Microchip Technology 25AA02E64T-I/SN

Overview

25AA02E64T-I/SN from Microchip Technology Inc. is a 2 Kbit SPI serial EEPROM with factory-programmed, globally unique EUI-64™ node address stored at addresses 0xF8–0xFF. It operates from 1.8V to 5.5V, supports up to 10 MHz clock frequency at 4.5–5.5V, features 16-byte page write capability, and delivers 1,000,000 erase/write cycles with >200-year data retention. It is used in networked embedded systems for MAC address storage and device identity management.

For engineers reviewing the 25AA02E64T-I/SN datasheet, 25AA02E64T-I/SN pinout, 25AA02E64T-I/SN application, or 25AA02E64T-I/SN equivalent, key selection criteria include EUI-64™ preprogramming integrity, SPI timing compliance across 1.8–5.5V supply, hardware write protection via WP pin, and industrial temperature operation (−40°C to +85°C) without derating.

Technical Context

The 25AA02E64T-I/SN implements a standard SPI Mode 0,0 interface (CPOL = 0, CPHA = 0) with separate SI and SO lines, requiring CS, SCK, SI, SO, WP, HOLD, VCC, and VSS. Its internal architecture includes an 8-bit instruction register, page latches, and HV generator for EEPROM programming.

It supports sequential read, byte/page write, and status register polling (WIP bit) during internal write cycles. Block protection is configurable via BP0/BP1 bits to lock none, upper 1/4 (C0h–FFh), upper 1/2 (80h–FFh), or full array - with factory default protecting the EUI-64™ block (C0h–FFh).

Key Specifications

Pinout & Package

25AA02E64T-I/SN is packaged in an 8-lead SOIC (SN) with 3.90 mm body width, RoHS-compliant matte tin plating, and JEDEC-standard footprint. Pin 1 is marked by a beveled corner or notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA02E64T-I/SN, the 25AA02E48T-I/SN offers identical reliability and interface but requires software-level EUI-64™ derivation, while AT25DF021A-SSH-T provides larger capacity at the cost of missing factory identity and dedicated protection features essential for secure device onboarding.

Availability

25AA02E64T-I/SN is available at Aetrix Electronics and suitable for network interface cards, IoT edge devices, industrial controllers, and medical equipment requiring stable component supply with guaranteed EUI-64™ identity integrity.

Supply support for 25AA02E64T-I/SN 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 Inc. is a leading provider of microcontrollers, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25AA02EXX product line was designed specifically for embedded systems requiring tamper-resistant, factory-provisioned IEEE-compliant node identities in minimal footprint SPI EEPROMs.

FAQ

What is the factory-programmed node address format for the 25AA02E64T-I/SN?

The 25AA02E64T-I/SN contains a factory-programmed, globally unique EUI-64™ node address stored in memory locations 0xF8 through 0xFF. This 8-byte value complies fully with IEEE EUI-64™ standards and is write-protected by default using BP0/BP1 bits to prevent accidental overwrite. The address includes Microchip's IEEE-assigned OUI followed by a unique 40-bit extension identifier generated during manufacturing. No user programming is required to access this identity via standard SPI read commands.

Does the 25AA02E64T-I/SN support SPI Mode 0,0 exclusively?

Yes, the 25AA02E64T-I/SN operates strictly in SPI Mode 0,0 (CPOL = 0, CPHA = 0), where data is sampled on the rising edge of SCK and output on the falling edge. It does not support Mode 1,1 or other variants. This fixed mode simplifies integration with Microchip PIC® MCUs and most ARM Cortex-M SPI peripherals without clock polarity or phase configuration overhead. All timing parameters in DS20002123G assume this mode.

How does the WP pin interact with the write-enable latch in the 25AA02E64T-I/SN?

In the 25AA02E64T-I/SN, the WP pin provides hardware-level write inhibition that overrides the software-controlled write-enable latch (WEL). When WP is low, all writes to memory and the STATUS register are blocked regardless of WEL state. Pulling WP low also resets the WEL latch. However, if a write cycle is already in progress when WP goes low, that cycle completes normally. This dual-layer protection ensures robustness against power glitches or firmware errors.

Can the 25AA02E64T-I/SN be used at 1.8V supply while maintaining 10 MHz SPI operation?

No. At VCC = 1.8V, the 25AA02E64T-I/SN maximum clock frequency is limited to 3 MHz per Table 1-2 AC CHARACTERISTICS. The 10 MHz rating applies only when VCC is between 4.5V and 5.5V. At 2.5V ≤ VCC < 4.5V, the limit is 5 MHz. Designers must scale SPI clock rate according to actual VCC to ensure setup/hold timing compliance - especially critical for HOLD and CS timing margins.

Is the HOLD function of the 25AA02E64T-I/SN compatible with all SPI master implementations?

The HOLD function requires precise timing: HOLD must be asserted while SCK is low to pause an ongoing transaction, and released while SCK is low to resume. Not all SPI masters automatically meet this constraint - particularly those lacking direct GPIO control of HOLD or using fixed clock-phase logic. Successful use depends on host firmware explicitly managing HOLD transitions synchronized to SCK edges. The feature is fully supported in Microchip's PIC® MCU SPI drivers and verified reference designs.