Microchip Technology 24AA128-I/SM

Overview

24AA128-I/SM from Microchip Technology Inc. is a 128 Kbit (16K × 8) I²C-compatible serial EEPROM with 1.7V–5.5V single-supply operation, 400 kHz max clock frequency, and industrial temperature range (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protect (WP), Schmitt-trigger inputs, and >1 million erase/write cycles - deployed in embedded system configuration storage, sensor calibration data retention, and power-fail-safe parameter backup.

For engineers reviewing the 24AA128-I/SM datasheet, 24AA128-I/SM pinout, 24AA128-I/SM application, or 24AA128-I/SM equivalent, this page delivers verified electrical specs, package mapping to SOIC-8 (SM), I²C timing constraints at 1.7V–5.5V, WP-controlled write protection behavior, and validated alternatives for industrial-grade nonvolatile memory replacement.

Technical Context

The 24AA128-I/SM implements a two-wire I²C slave interface with fixed 4-bit control code (1010b) and user-configurable A2/A1/A0 address bits enabling up to eight devices on one bus. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and address pointer logic supporting current-address, random, and sequential reads across the full 0000h–3FFFh address space.

Write operations are self-timed with maximum 5 ms byte/page cycle time; acknowledge polling is supported to detect completion. The device uses open-drain SDA/SCL with internal Schmitt triggers (V_HYS ≥ 0.05×V_CC) and slope control to suppress ground bounce - ensuring robust noise immunity in mixed-signal environments.

Key Specifications

Pinout & Package

24AA128-I/SM is packaged in 8-lead SOIC (SN) with body width 3.90 mm, marked "24AA128-I/SM" per Microchip drawing C04-057-SN Rev E. Pin 1 is top-left corner with notch or dot indicator.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA128-I/SM, the 24LC128-I/SM offers identical form/fit/function at higher minimum voltage, while the AT24C128N-10PU-2.7 trades automotive reliability and ESD robustness for broader voltage compatibility and lower unit cost in non-automotive applications.

Availability

24AA128-I/SM is available at Aetrix Electronics and suitable for industrial PLC configuration storage, medical device calibration data retention, and automotive body control module settings requiring stable component supply across extended product lifecycles.

Supply support for 24AA128-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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions for embedded control applications.

The 24AA128-I/SM belongs to Microchip's 24XX128 family of I²C EEPROMs designed for low-power, high-reliability nonvolatile data storage in space-constrained industrial, medical, and automotive systems.

FAQ

What is the minimum V_CC required for reliable operation of the 24AA128-I/SM?

The 24AA128-I/SM operates reliably from 1.7V to 5.5V. At V_CC < 2.5V, maximum I²C clock frequency is limited to 100 kHz to maintain timing margins; full 400 kHz operation is guaranteed only at V_CC ≥ 2.5V. This allows direct interfacing with 1.8V microcontrollers while preserving timing compliance - a key advantage over the 24LC128-I/SM, which requires ≥2.5V.

How does the WP pin function on the 24AA128-I/SM during active write cycles?

The WP pin on the 24AA128-I/SM is sampled only at the Stop condition of each write command. If WP is high at that instant, the entire write operation (byte or page) is inhibited - no data is written, no erase occurs, and the device immediately accepts the next command. Toggling WP during an ongoing write has no effect; protection is strictly edge-triggered at Stop.

Can the 24AA128-I/SM perform sequential reads across its full 128 Kbit memory space?

Yes - the 24AA128-I/SM supports true sequential reads across the entire 0000h–3FFFh address range. After transmitting the initial address, the internal address pointer auto-increments on each byte transfer. Upon reaching 3FFFh, it rolls over to 0000h, enabling continuous streaming without host-side address management - essential for firmware parameter dumps or log file retrieval.

What is the maximum number of 24AA128-I/SM devices that can share a single I²C bus?

Up to eight 24AA128-I/SM devices can be cascaded on one I²C bus using unique combinations of A2/A1/A0 address pins. Each device responds only to its assigned 7-bit slave address (1010 A2 A1 A0), enabling expansion to 1 Mbit total addressable space. For SOIC-8 (SM) packages, all three address pins are functional and must be hardwired to VSS or VCC.

Does the 24AA128-I/SM support page write operations across physical page boundaries?

No - page write operations on the 24AA128-I/SM are strictly confined within 64-byte physical page boundaries (e.g., 0000h–003Fh, 0040h–007Fh). Attempting to write across a boundary causes wraparound within the current page, overwriting earlier bytes. Application firmware must enforce page alignment; the device does not auto-split writes across pages.