Microchip Technology 24AA025UID-I/P

Overview

24AA025UID-I/P from Microchip Technology is a 2 Kbit I²C-compatible serial EEPROM with a factory-programmed, globally unique 32-bit serial number stored in write-protected memory (addresses 0xFC–0xFF). It operates from 1.7V to 5.5V, supports 400 kHz clock (100 kHz below 2.5V), and delivers ultra-low standby current (1 µA max) for battery-sensitive applications such as secure device authentication in IoT edge nodes.

For engineers reviewing the 24AA025UID-I/P datasheet, 24AA025UID-I/P pinout, 24AA025UID-I/P application, or 24AA025UID-I/P equivalent, key selection criteria include its preprogrammed UID integrity, 16-byte page write buffer, industrial temperature range (−40°C to +85°C), I²C bus noise immunity via Schmitt-trigger inputs, and compatibility with standard 8-lead PDIP packaging.

Technical Context

The 24AA025UID-I/P implements a two-wire I²C slave interface with fixed 7-bit address prefix '1010' and three programmable chip-select bits (A2/A1/A0), enabling up to eight devices on one bus. Its internal architecture includes a write-protect circuit that permanently locks the upper half of memory (0x80–0xFF), reserving 0xFC–0xFF exclusively for the immutable UID and manufacturer/device codes (0xFA = 0x29, 0xFB = 0x41).

It uses low-power CMOS technology with self-timed erase/write cycles (5 ms max), on-chip page buffer (16 bytes), and VCC threshold detection that disables writes below 1.5V. All I/O pins feature Schmitt-trigger inputs and output slope control to suppress ground bounce and bus noise-critical for reliable operation in electrically noisy industrial environments.

Key Specifications

Pinout & Package

24AA025UID-I/P is supplied in an 8-lead plastic dual in-line package (PDIP), with 0.300-inch body width and through-hole mounting. Pin 1 is identified by a laser mark or notch; pin 4 is VSS (ground), pin 5 is SDA (bidirectional open-drain I²C data), pin 6 is SCL (input-only I²C clock), and pin 8 is VCC (1.7–5.5V supply). Pins A0, A1, and A2 are functional for device addressing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA025UID-I/P, the 24AA02UID-I/P offers identical UID security but reduced page buffer and addressing flexibility, while the AT24CM01 requires UID programming and lacks factory guarantee of global uniqueness - making 24AA025UID-I/P optimal for zero-touch, high-integrity device identity.

Availability

24AA025UID-I/P is available at Aetrix Electronics and suitable for secure device authentication, industrial sensor node ID, and IoT edge gateway identity requiring stable component supply across automotive-grade temperature ranges and long product lifecycles.

Supply support for 24AA025UID-I/P 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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24AA02XUID family was designed specifically for secure hardware identity management in resource-constrained embedded systems, delivering factory-programmed uniqueness with minimal power and interface overhead.

FAQ

What is the exact memory organization of the 24AA025UID-I/P?

The 24AA025UID-I/P contains 2 Kbit (256 bytes) of EEPROM arranged as two 128-word blocks. The lower half (0x00–0x7F) is user-writable; the upper half (0x80–0xFF) is write-protected. The 32-bit UID resides at 0xFC–0xFF, with manufacturer code (0x29) at 0xFA and device ID (0x41) at 0xFB. This layout is fixed and cannot be altered.

Does the 24AA025UID-I/P require external pull-up resistors on SDA and SCL lines?

Yes, the 24AA025UID-I/P has open-drain SDA and input-only SCL pins, mandating external pull-up resistors. For 400 kHz operation, a 2 kΩ resistor to VCC is recommended; for 100 kHz, 10 kΩ is typical. Pull-ups must be placed close to the 24AA025UID-I/P to maintain signal integrity and meet I²C rise time specifications.

Can the factory-programmed UID in the 24AA025UID-I/P be modified or erased?

No. The 32-bit UID in the 24AA025UID-I/P is programmed during wafer sort and permanently locked in the write-protected memory region (0xFC–0xFF). Hardware-level protection prevents any write or erase command from altering this area - even under elevated voltage or extended programming cycles.

How does the 24AA025UID-I/P handle I²C bus contention or noise?

It employs Schmitt-trigger inputs on SDA and SCL with 50 ns spike suppression filtering and hysteresis (0.05×VCC), rejecting transient noise that could cause false start/stop conditions. Output slope control minimizes ground bounce during switching, and the VCC threshold detector disables writes below 1.5V to prevent corruption during brown-out.

Is the 24AA025UID-I/P compatible with standard I²C protocol analyzers and debug tools?

Yes. The 24AA025UID-I/P fully complies with the NXP I²C-bus specification (standard-mode and fast-mode), supporting standard START/STOP, ACK/NACK, and address/data framing. It responds to the fixed 7-bit address prefix '1010' followed by configurable A2/A1/A0 bits and R/W bit - visible and decodable by all mainstream I²C protocol analyzers.