Microchip Technology 24AA256-I/P

Overview

24AA256-I/P from Microchip Technology is a 256-Kbit I²C serial EEPROM with 32K × 8 organization, operating from 1.7V to 5.5V, supporting up to 400 kHz clock frequency at industrial temperature (−40°C to +85°C), featuring 64-byte page write buffer, hardware write-protect (WP pin), and >1 million erase/write cycles. It is used in embedded systems for parameter storage, calibration data retention, and firmware configuration in low-power sensor nodes and industrial controllers.

For engineers reviewing the 24AA256-I/P datasheet, 24AA256-I/P pinout, 24AA256-I/P application, or 24AA256-I/P equivalent, key selection considerations include VCC range compatibility (1.7–5.5V), I²C timing compliance (400 kHz max at ≥2.5V), WP-enabled hardware protection, cascading capability (up to eight devices), and industrial-grade temperature operation.

Technical Context

The 24AA256-I/P implements a two-wire I²C-compatible interface with Schmitt-trigger inputs on SDA/SCL for noise immunity and slope-controlled outputs to suppress ground bounce. Its internal architecture includes a 64-byte page latch, address pointer, and HV generator for EEPROM programming.

It supports byte and page write modes with self-timed erase/write cycles (≤5 ms), acknowledges only after successful command receipt, and suspends ACK during internal write-enabling reliable acknowledge polling. Addressing uses three chip-select bits (A0–A2) for multi-device bus configuration, with fixed '1010' control code and R/W bit.

Key Specifications

Pinout & Package

24AA256-I/P is supplied in an 8-lead PDIP (Plastic Dual In-line Package) with 0.300-inch body width, through-hole mounting, and industry-standard pin spacing (0.100 inch). The package is RoHS-compliant and rated for industrial temperature operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC256-I/P, the 24AA256-I/P enables lower-voltage operation critical for energy-harvesting sensors, while versus AT24C256-10PU-2.7, it delivers 10× higher endurance and faster 5 ms writes-making it superior for high-write-frequency industrial logging.

Availability

24AA256-I/P is available at Aetrix Electronics and suitable for smart metering, industrial PLC configuration, medical sensor calibration, and automotive body control module applications requiring stable component supply, long-lifecycle assurance, and RoHS-compliant sourcing.

Supply support for 24AA256-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, serving industrial, automotive, communications, and consumer markets with vertically integrated silicon and software platforms.

The 24AA256 belongs to Microchip's 24XX256 family of I²C serial EEPROMs, designed specifically for robust, low-power, nonvolatile data storage in space-constrained embedded systems requiring extended reliability and broad voltage operation.

FAQ

What is the maximum I²C clock frequency supported by the 24AA256-I/P?

The 24AA256-I/P supports up to 400 kHz I²C clock frequency when VCC is ≥2.5V. At VCC < 2.5V (e.g., 1.8V operation), the maximum clock rate is limited to 100 kHz per DS20001203Y specification. This dual-speed capability ensures interoperability across both legacy 3.3V/5V and modern ultra-low-power 1.8V systems without protocol changes.

Does the 24AA256-I/P require external pull-up resistors on SDA and SCL lines?

Yes, the 24AA256-I/P requires external pull-up resistors on both SDA and SCL lines because its I/O pins are open-drain. Recommended values are 10 kΩ for 100 kHz operation, 2 kΩ for 400 kHz, and ≤1 kΩ for marginal noise environments. These resistors establish valid high logic levels and ensure proper rise times per I²C bus specifications.

How does hardware write-protection work on the 24AA256-I/P?

Hardware write-protection on the 24AA256-I/P is controlled by the WP pin: when tied to VCC, all write operations (byte and page) are inhibited while read operations remain fully functional. The WP state is sampled at the STOP condition of each write command, making protection active before any internal programming begins-preventing corruption during brown-out or reset events.

Can multiple 24AA256-I/P devices share the same I²C bus?

Yes, up to eight 24AA256-I/P devices can share a single I²C bus using the A0, A1, and A2 address pins to configure unique 3-bit device addresses. Each device must have a distinct combination of these pins tied to VSS or VCC. For the PDIP package, all three pins are functional, enabling full 8-device addressing as specified in the device selection table.

What is the page write buffer size of the 24AA256-I/P, and why does it matter?

The 24AA256-I/P features a 64-byte page write buffer, allowing up to 64 bytes to be written in a single I²C transaction. This reduces bus overhead and total write time versus byte-by-byte writes, and-critically-limits wear to one page per transaction instead of one byte, extending effective endurance to 1 million cycles per page rather than per byte.