Microchip Technology AT24C256W-10SI-2.7-T

Overview

AT24C256W-10SI-2.7-T from Microchip Technology (formerly Atmel) is a 256 Kbit (32,768 × 8) two-wire serial EEPROM optimized for low-voltage industrial applications. It operates from 2.7V to 5.5V, supports up to 1 MHz I²C bus speed at 5V, features hardware write protection via the WP pin, and delivers 1 million write cycles with 40-year data retention. It is commonly used in embedded systems for storing calibration data, configuration parameters, and firmware boot settings.

For engineers reviewing the AT24C256W-10SI-2.7-T datasheet, AT24C256W-10SI-2.7-T pinout, AT24C256W-10SI-2.7-T application, or AT24C256W-10SI-2.7-T equivalent, this page provides verified electrical specifications, JEDEC SOIC-8 package details, I²C timing compatibility across voltage grades, endurance and retention metrics, and validated alternative parts for design continuity.

Technical Context

The AT24C256W-10SI-2.7-T implements a standard I²C-compatible two-wire interface with open-drain SDA and Schmitt-triggered SCL inputs for noise immunity. It uses internal address latching and auto-incrementing during sequential reads, supporting byte-write and 64-byte page-write modes with self-timed internal write cycles.

Device addressing uses A1/A0 pins to enable up to four devices on a shared bus; WP pin enables hardware-level memory write protection. The part is qualified for industrial temperature range (–40°C to +85°C) and supports acknowledge polling to detect write completion without fixed delay timing.

Key Specifications

Pinout & Package

AT24C256W-10SI-2.7-T is housed in an 8-lead JEDEC SOIC (8S1) package, 0.150" wide body, with gull-wing leads and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C256W-10SI-2.7-T, the M24256-BWMN6TP trades speed and endurance for lower unit cost, while the CAT24C256WI-GT3 matches speed but halves retention time - making AT24C256W-10SI-2.7-T optimal for mission-critical industrial deployments demanding both performance and longevity.

Availability

AT24C256W-10SI-2.7-T is available at Aetrix Electronics and suitable for smart energy metering, industrial PLC configuration, medical diagnostics, and automotive body control modules requiring stable component supply across multi-year production cycles.

Supply support for AT24C256W-10SI-2.7-T 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 acquired Atmel in 2016 and maintains full product support, qualification, and manufacturing continuity for the AT24Cxx EEPROM family.

The AT24C256W-10SI-2.7-T belongs to Microchip's industrial-grade serial EEPROM product line, designed specifically for robust, low-power nonvolatile storage in harsh environments with stringent reliability and longevity requirements.

FAQ

What is the maximum I²C clock frequency supported by the AT24C256W-10SI-2.7-T?

The AT24C256W-10SI-2.7-T supports up to 1 MHz I²C clock frequency when operated at VCC = 5.0 V. At 2.7 V, the maximum guaranteed clock rate is 400 kHz. These values are specified in the AC Characteristics table and apply across the full industrial temperature range (–40°C to +85°C). The AT24C256W-10SI-2.7-T does not support 1 MHz operation below 4.5 V.

Does the AT24C256W-10SI-2.7-T require external pull-up resistors on SDA and SCL lines?

Yes, the AT24C256W-10SI-2.7-T requires external pull-up resistors on both SDA and SCL lines because its SDA pin is open-drain and SCL input is passive. Typical values range from 2.2 kΩ to 10 kΩ depending on bus capacitance and speed; 4.7 kΩ is commonly used for 400 kHz operation with ≤400 pF total bus capacitance. The AT24C256W-10SI-2.7-T itself does not integrate pull-ups.

How many devices can share the same I²C bus with the AT24C256W-10SI-2.7-T?

Up to four AT24C256W-10SI-2.7-T devices can share a single I²C bus using hardwired A1 and A0 pins to configure unique 7-bit device addresses. Each combination of A1/A0 (00, 01, 10, 11) yields a distinct address (0x50–0x53). Floating A1/A0 is not recommended - datasheet specifies internal weak pull-downs only under strict board coupling conditions (<3 pF).

What is the function of the WP pin on the AT24C256W-10SI-2.7-T?

The WP (Write Protect) pin on the AT24C256W-10SI-2.7-T is a hardware-level enable/disable control for all write operations. When WP is tied to VCC, all writes to memory are inhibited - reads remain fully functional. When WP is tied to GND, normal read/write access is enabled. Leaving WP floating is not recommended due to uncertain internal biasing behavior.

Is the AT24C256W-10SI-2.7-T compatible with 1.8 V I²C systems?

No, the AT24C256W-10SI-2.7-T is a 2.7 V–5.5 V device and is not rated for 1.8 V operation. For 1.8 V systems, Microchip offers the AT24C256W-10SI-1.8-T variant, which supports 1.8 V–3.6 V and operates at up to 100 kHz. Mixing voltage grades risks unreliable communication or damage; always match VCC and I²C bus voltage to the specific suffix (-2.7 or -1.8).