Microchip Technology 25AA02E64T-I/OT

Overview

25AA02E64T-I/OT 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 features 256 × 8-bit organization, 16-byte page write capability, 10 MHz max clock (at VCC ≥ 4.5V), and industrial temperature range (−40°C to +85°C). It is used for secure device identity storage in networked embedded systems requiring IEEE-compliant 64-bit addressing.

For engineers reviewing the 25AA02E64T-I/OT datasheet, 25AA02E64T-I/OT pinout, 25AA02E64T-I/OT application, or 25AA02E64T-I/OT equivalent, this page delivers verified electrical specs, SPI timing constraints, EUI-64™ memory mapping, write-protection behavior, and validated alternative parts - all confirmed against Microchip DS20002123G.

Technical Context

The 25AA02E64T-I/OT implements a standard SPI Mode 0,0 interface (CPOL = 0, CPHA = 0) with separate SI/SO lines and active-low CS. Its internal architecture includes a write-enable latch, STATUS register with WIP/WEL/BP bits, and hardware WP and HOLD pins for real-time bus arbitration and data integrity control.

It supports byte and page writes (up to 16 bytes within one 16-byte page boundary), automatic address roll-over during sequential reads, and factory-configured BP1/BP0 = 0/1 to protect the upper 1/4 array (0xC0–0xFF) containing the EUI-64™ address - writable only after issuing WRSR to clear protection.

Key Specifications

Pinout & Package

25AA02E64T-I/OT is packaged in a 6-lead SOT-23 (OT) surface-mount package, measuring 2.9 mm × 1.6 mm × 1.1 mm, with gull-wing leads and RoHS-compliant matte tin plating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM with factory-programmed node identity applications.

Compared with 25AA02E48T-I/OT, the 25AA02E64T-I/OT delivers native EUI-64™ support eliminating software conversion, while AT24C02C-SSHM-T offers I²C compatibility but requires full identity provisioning - making 25AA02E64T-I/OT optimal for SPI-based, standards-compliant embedded identity.

Availability

25AA02E64T-I/OT is available at Aetrix Electronics and suitable for industrial Ethernet node identity, IoT edge device authentication, medical UDI compliance, and automotive telematics module applications requiring stable component supply and long-term lifecycle assurance.

Supply support for 25AA02E64T-I/OT 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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25AA02EXX product line delivers factory-programmed, standards-compliant node identity storage for embedded systems requiring IEEE EUI-48™ or EUI-64™ addressing without external provisioning infrastructure.

FAQ

What is the exact memory organization and EUI-64™ address location for 25AA02E64T-I/OT?

The 25AA02E64T-I/OT contains 256 bytes (2 Kbit) of EEPROM organized as 256 × 8-bit. Its factory-programmed 8-byte EUI-64™ node address is permanently stored in memory locations 0xF8 through 0xFF. This block is write-protected by default via STATUS register BP1/BP0 = 0/1, covering the upper 1/4 (0xC0–0xFF) of the array.

Does 25AA02E64T-I/OT support SPI Mode 0,0 exclusively, and what are the timing constraints at 3.3V?

Yes, 25AA02E64T-I/OT operates strictly in SPI Mode 0,0 (CPOL = 0, CPHA = 0). At VCC = 3.3V (within 2.5V–4.5V range), maximum clock frequency is 5 MHz. AC timing parameters including TCSS (CS setup), THD (data hold), and TV (output valid) scale accordingly - e.g., TCSS ≤ 200 ns, THD ≥ 40 ns, TV ≤ 100 ns - per Table 1-2 of DS20002123G.

How does the HOLD pin function during an active SPI read sequence on 25AA02E64T-I/OT?

During an active SPI read, pulling HOLD low (while SCK is low) pauses communication without resetting the internal address pointer or transaction state. SI, SCK, and SO enter high-impedance; only CS must remain low. Upon returning HOLD high (with SCK low), the 25AA02E64T-I/OT resumes exactly where it left off - shifting out the next byte from the current address - enabling interrupt-safe operation.

Can the factory-programmed EUI-64™ address in 25AA02E64T-I/OT be overwritten, and what safeguards exist?

The EUI-64™ address in 25AA02E64T-I/OT resides in protected memory (0xF8–0xFF) and cannot be overwritten unless BP1/BP0 bits in the STATUS register are first cleared via WRSR instruction. Even then, writing to that region requires explicit WREN activation and proper page alignment. Factory default BP1/BP0 = 0/1 prevents accidental modification - a key safeguard for identity integrity.

What are the standby and operating current specifications for 25AA02E64T-I/OT at 1.8V and 5.5V?

At VCC = 1.8V, ICCS (standby current) is ≤1 µA (TA = +85°C), and ICCREAD is ≤2.5 mA (FCLK = 3 MHz). At VCC = 5.5V, ICCREAD is ≤5 mA (FCLK = 10 MHz), and ICCWRITE is ≤5 mA. These values are measured under specified test conditions in Tables 1-1 and 1-2 of DS20002123G and confirm suitability for both ultra-low-power and high-speed applications.