Microchip Technology 24AA025E64T-E/OT

Overview

24AA025E64T-E/OT from Microchip Technology Inc. is a 2 Kbit I²C-compatible serial EEPROM with factory-programmed, globally unique EUI-64™ node address stored in write-protected memory (0xF8–0xFF). It operates from 1.7V to 5.5V, supports 400 kHz I²C clock (100 kHz at VCC < 2.5V), and features 16-byte page write capability. Used for secure device identity storage in industrial Ethernet nodes and IoT edge sensors.

For engineers reviewing the 24AA025E64T-E/OT datasheet, 24AA025E64T-E/OT pinout, 24AA025E64T-E/OT application, or 24AA025E64T-E/OT equivalent, key selection criteria include EUI-64™ pre-programming integrity, I²C timing compliance at low voltage (1.7V), cascading support via A0/A1 address pins, and automotive-grade (-40°C to +125°C) operation with ≤5 µA standby current.

Technical Context

The 24AA025E64T-E/OT implements a two-block 128 × 8-bit EEPROM array with hardware write protection on upper half (0x80–0xFF). Its I²C slave interface uses Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce on shared buses.

It supports cascaded addressing: A0 and A1 pins enable up to four devices on the same bus in 6-lead SOT-23 (A2 not bonded); each device responds only when its chip address bits match the control byte's A1/A0 bits. Internal address pointer auto-increments during sequential reads across the full 256-byte space.

Key Specifications

Pinout & Package

Package: 6-lead SOT-23 (JEDEC MO-178AA), 1.6 mm × 2.8 mm footprint, 1.1 mm height, matte tin lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA025E64T-E/OT, the 24AA02E64T-E/OT offers identical EUI-64™ and temperature rating but omits cascading - limiting multi-device integration. The AT24CM02-SSHM-T provides EUI-64™ in SOIC-8 but lacks SOT-23 and address pin flexibility, increasing PCB area and reducing system scalability.

Availability

24AA025E64T-E/OT is available at Aetrix Electronics and suitable for industrial automation, automotive telematics, and medical diagnostics requiring stable component supply with guaranteed automotive-grade qualification and long-term lifecycle support.

Supply support for 24AA025E64T-E/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 components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24AA025E64T-E/OT belongs to Microchip's 24AA02XEXX family of pre-programmed identity EEPROMs, designed specifically for secure, standards-compliant device identification in industrial, automotive, and IoT systems where hardware-rooted uniqueness is mandatory.

FAQ

What is the exact memory organization and protected region of the 24AA025E64T-E/OT?

The 24AA025E64T-E/OT contains 256 bytes (2 Kbit) of EEPROM organized as two 128-word blocks. The upper half (addresses 0x80–0xFF) is permanently write-protected and holds the factory-programmed EUI-64™ node address (0xF8–0xFF). The lower half (0x00–0x7F) is user-writable. This architecture ensures the EUI-64™ remains immutable while allowing application data storage in the accessible region. The 24AA025E64T-E/OT enforces this protection at the silicon level - no software or command can override it.

Does the 24AA025E64T-E/OT support cascading on I²C, and how many devices can share one bus?

Yes, the 24AA025E64T-E/OT supports cascading via its A0 and A1 pins, enabling up to four devices on a single I²C bus in the 6-lead SOT-23 package (A2 is not bonded). Each device responds only when its A1/A0 logic levels match the corresponding bits in the I²C control byte. This allows contiguous 16K-bit expansion across multiple 24AA025E64T-E/OT units. The 24AA025E64T-E/OT's cascading capability eliminates external address jumpers and simplifies multi-sensor node design.

What are the I²C timing constraints for the 24AA025E64T-E/OT at 1.7V supply?

At VCC = 1.7V, the 24AA025E64T-E/OT supports a maximum I²C clock frequency of 100 kHz. Key AC parameters include minimum SCL low time of 4700 ns, minimum SCL high time of 4000 ns, and maximum SDA/SCL rise time of 1000 ns. These relaxed timings accommodate slower pull-up networks required for ultra-low-voltage operation while maintaining noise immunity via Schmitt-trigger inputs. The 24AA025E64T-E/OT's timing compliance at 1.7V enables direct interfacing with energy-harvesting power sources without level-shifting.

How is the EUI-64™ address physically stored and accessed in the 24AA025E64T-E/OT?

The EUI-64™ address in the 24AA025E64T-E/OT is factory-programmed into memory locations 0xF8 through 0xFF (eight consecutive bytes) and resides in the write-protected upper block. It is read using standard I²C random or sequential read commands - no special instructions are needed. The 24AA025E64T-E/OT returns the full 64-bit value upon reading those addresses, and the hardware lock prevents any overwrite attempts, ensuring IEEE compliance and long-term identity integrity across the device's operational life.

Is the 24AA025E64T-E/OT qualified for automotive applications, and what is its temperature range?

Yes, the 24AA025E64T-E/OT is explicitly qualified for automotive applications with an extended temperature range of -40°C to +125°C (E-grade). It meets AEC-Q100 stress test requirements for reliability and is specified for ≤5 µA standby current across this full range. This makes the 24AA025E64T-E/OT suitable for under-hood telematics, ADAS domain controllers, and infotainment systems where thermal stability and low-power operation are critical. The 24AA025E64T-E/OT's automotive qualification is documented in Microchip's official DS20002124H datasheet.