Microchip Technology AT24C256W-10SC

Overview

AT24C256W-10SC from Microchip Technology (formerly Atmel) is a 256 Kbit (32,768 × 8) I²C-compatible serial EEPROM with low-voltage operation (2.7V to 5.5V), 400 kHz bus speed at 2.7V, and hardware write protection via the WP pin. It supports 64-byte page writes, features Schmitt-trigger inputs for noise immunity, and delivers 100,000 write cycles with 40-year data retention - deployed in industrial control modules requiring nonvolatile parameter storage across power cycles.

For engineers reviewing the AT24C256W-10SC datasheet, AT24C256W-10SC pinout, AT24C256W-10SC application, or AT24C256W-10SC equivalent, key selection criteria include its 2.7V–5.5V supply range, 8-pin SOIC (8S2) package, 400 kHz I²C timing compliance at 2.7V, WP-enabled hardware data protection, and cascading support for up to four devices on one bus.

Technical Context

The AT24C256W-10SC implements a standard two-wire I²C interface with open-drain SDA/SCL pins, internal address latching via A0/A1 pins, and a dedicated Write Protect (WP) input that disables all write operations when driven high. Its memory is organized as 512 pages of 64 bytes each, enabling efficient partial-page writes without cross-page rollover.

It uses an internally timed 10 ms typical write cycle (tWR), supports acknowledge polling for write completion detection, and incorporates Schmitt-triggered inputs with filtered logic to suppress system-level noise - critical for reliable operation in electrically noisy industrial environments where VCC may dip near 2.7V.

Key Specifications

Pinout & Package

AT24C256W-10SC is supplied in an 8-lead, 0.200" wide Plastic Gull Wing Small Outline Package (EIAJ SOIC), designated as 8S2 per Microchip's ordering guide. This surface-mount package measures 4.90 mm × 6.00 mm with 1.27 mm lead pitch and is RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M24C256-WMN6TP and BR24G256FJ-WE2, the AT24C256W-10SC offers guaranteed pin-compatible replacement within the Atmel/Microchip 8S2 SOIC family, integrated hardware WP, and validated 400 kHz performance at 2.7V - making it optimal for industrial designs requiring proven noise immunity and layout continuity.

Availability

AT24C256W-10SC is available at Aetrix Electronics and suitable for industrial automation, smart metering, medical device configuration, and automotive body electronics requiring stable component supply across extended product lifecycles.

Supply support for AT24C256W-10SC 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 is a global semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with a focus on reliability and long-term product availability for industrial and automotive markets.

The AT24C256W-10SC belongs to Microchip's legacy AT24C serial EEPROM product line, engineered for robust nonvolatile data storage in resource-constrained embedded systems operating across wide voltage and temperature ranges.

FAQ

What is the maximum I²C clock frequency supported by the AT24C256W-10SC at 2.7V?

The AT24C256W-10SC supports up to 400 kHz I²C clock frequency when operated at 2.7V, as specified in Microchip's AC Characteristics table. This is lower than its 1 MHz rating at 5.0V but ensures reliable timing margin under low-voltage conditions typical in battery-backed or energy-harvesting systems. The AT24C256W-10SC maintains full functionality across its 2.7V–5.5V range without mode switching.

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

Yes, the AT24C256W-10SC requires external pull-up resistors on both SDA and SCL lines because these pins are open-drain. Typical values range from 2.2 kΩ to 10 kΩ depending on bus capacitance and speed; Microchip recommends 4.7 kΩ for 400 kHz operation with ≤400 pF total bus capacitance. The AT24C256W-10SC does not include internal pull-ups.

How does the Write Protect (WP) pin function on the AT24C256W-10SC?

The WP pin on the AT24C256W-10SC is an active-high hardware lock: when pulled to VCC, it disables all write operations including byte, page, and erase commands - even if correct I²C addresses and data are sent. When grounded or left floating (internally pulled down), writes are enabled. This provides fail-safe protection against unintended memory corruption during power-up or firmware errors in the AT24C256W-10SC system.

What package type is used for the AT24C256W-10SC, and is it RoHS-compliant?

The AT24C256W-10SC uses an 8-lead, 0.200" wide Plastic Gull Wing Small Outline Package (EIAJ SOIC), designated 8S2 in Microchip's ordering nomenclature. Its dimensions are 4.90 mm × 6.00 mm with 1.27 mm lead pitch. Yes, this package is RoHS-compliant and halogen-free, meeting JEDEC standard MS-012AB, and is compatible with standard reflow soldering profiles.

Can multiple AT24C256W-10SC devices share the same I²C bus?

Yes, up to four AT24C256W-10SC devices can share a single I²C bus using hardware address configuration via the A0 and A1 pins. Each device responds to a unique 7-bit address (0x50–0x53) based on A0/A1 logic levels. The AT24C256W-10SC supports this cascading natively without additional logic, enabling compact multi-parameter storage in space-constrained designs.