Microchip Technology 24AA1025-I/SM

Overview

24AA1025-I/SM from Microchip Technology Inc. is a 128K × 8 (1024 kbit) I²C-compatible serial EEPROM with 1.7–5.5 V operation, 400 kHz max clock (100 kHz below 2.5 V), and industrial temperature range (–40°C to +85°C). It features 128-byte page write buffer, hardware write-protect (WP pin), and Schmitt-trigger inputs for noise immunity. Used in embedded systems for nonvolatile parameter storage, calibration data retention, and firmware configuration.

For engineers reviewing the 24AA1025-I/SM datasheet, 24AA1025-I/SM pinout, 24AA1025-I/SM application, or 24AA1025-I/SM equivalent, key selection criteria include voltage compatibility (1.7–5.5 V), I²C timing compliance at target VCC, page boundary handling in firmware, and WP pin logic behavior (VCC = write inhibit).

Technical Context

The 24AA1025-I/SM operates as an I²C slave device with fixed 4-bit control code (1010b) and user-configurable A0/A1 address bits enabling up to four devices on one bus. Its internal architecture includes dual 512 kbit memory segments accessed via block select bit (B0), requiring explicit segment switching for full 1 Mbit addressing.

It implements open-drain SDA/SCL interfaces with internal slope control and Schmitt-trigger inputs (VHYS ≥ 0.05×VCC), supporting reliable communication in noisy environments. Write operations are self-timed with typical 3 ms page write time and automatic wrap-around protection within 128-byte physical pages.

Key Specifications

Pinout & Package

24AA1025-I/SM is housed in an 8-lead SOIC (Small Outline Integrated Circuit) package with 3.90 mm body width, RoHS-compliant matte tin (Sn) finish, and standard 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC1025-I/P and AT24C1024-SSHL-T, the 24AA1025-I/SM uniquely supports full 400 kHz I²C operation down to 1.7 V while enforcing mandatory A2-to-VCC connection - simplifying design validation for ultra-low-voltage embedded systems without sacrificing industrial temperature rating or page-write efficiency.

Availability

24AA1025-I/SM is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control modules, and smart energy metering requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 24AA1025-I/SM 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 24AA1025-I/SM belongs to Microchip's 24XX serial EEPROM product line, engineered for ultra-low-power, high-reliability nonvolatile storage in space-constrained industrial and automotive applications where voltage flexibility and long-term data integrity are critical.

FAQ

What is the minimum supply voltage required for reliable operation of the 24AA1025-I/SM?

The 24AA1025-I/SM operates reliably from 1.7 V to 5.5 V. At VCC < 2.5 V, maximum I²C clock frequency is limited to 100 kHz, and DC characteristics such as VIH/VIL thresholds scale proportionally. This makes the 24AA1025-I/SM suitable for direct integration with 1.8 V microcontrollers without level-shifting circuitry, provided timing budgets accommodate reduced clock speed.

How does the A2 pin function on the 24AA1025-I/SM, and what happens if it is left unconnected?

The A2 pin on the 24AA1025-I/SM is a non-configurable chip select that must be hard-wired to VCC for normal operation. If left floating or tied to VSS, device operation becomes undefined - the IC will not respond to I²C commands or acknowledge addresses. This requirement is explicitly defined in the datasheet and differs from A0/A1, which are user-configurable address bits.

Can the 24AA1025-I/SM perform sequential reads across its full 1024 kbit address space without interruption?

No. The 24AA1025-I/SM divides its memory into two 512 kbit segments (00000h–0FFFFh and 10000h–1FFFFh), and sequential reads automatically roll over within each segment but cannot cross the 0FFFFh → 10000h boundary. To read the entire array sequentially, firmware must issue separate read commands with explicit block select bit (B0) toggling between segments.

What is the purpose of the WP pin on the 24AA1025-I/SM, and how does it affect write operations?

The WP (Write-Protect) pin on the 24AA1025-I/SM provides hardware-level write inhibition. When tied to VCC, all write operations (byte and page) are blocked - the device acknowledges the command but performs no EEPROM programming. When tied to VSS, full read/write capability is enabled. WP state is sampled at the Stop bit of each write command, making it effective for protecting configuration data during power transitions.

Does the 24AA1025-I/SM support page write operations across physical page boundaries, and what occurs if attempted?

No. Page write operations on the 24AA1025-I/SM are strictly confined within 128-byte physical pages. If a page write command attempts to cross a boundary (e.g., writing bytes ending at 0x007F and continuing to 0x0080), data wraps around to the start of the same page (0x0000), overwriting previously loaded data. Firmware must enforce page alignment - typically by masking address bits A6–A0 - before initiating multi-byte writes.