Microchip Technology 24FC256T-I/OT

Overview

24FC256T-I/OT from Microchip Technology Inc. is a 256-Kbit (32K × 8) I²C-compatible serial EEPROM with 1 MHz maximum clock frequency, 1.7V–5.5V supply range, and industrial temperature rating (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protect (WP), and Schmitt-trigger inputs for noise immunity-used in embedded system configuration storage, sensor calibration data retention, and firmware parameter backup.

For engineers reviewing the 24FC256T-I/OT datasheet, 24FC256T-I/OT pinout, 24FC256T-I/OT application, or 24FC256T-I/OT equivalent, key selection criteria include its 1 MHz I²C speed at full VCC, 5 ms max page write time, industrial-grade reliability (>1M write cycles, >200 years data retention), and SOT-23-5 package compatibility with space-constrained PCB layouts.

Technical Context

The 24FC256T-I/OT implements a two-wire I²C interface with programmable device addressing via A0–A2 pins (not present in SOT-23 package), supporting up to eight devices on one bus. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and memory control logic enabling self-timed erase/write cycles without external timing components.

Unlike 24AA256 and 24LC256 variants, the 24FC256T-I/OT supports 1 MHz I²C operation across the full 2.5V–5.5V VCC range and achieves 400 ns TAA (output valid from clock) at 5.5V-enabling faster read throughput in high-speed microcontroller interfaces while maintaining backward compatibility with 100 kHz/400 kHz systems.

Key Specifications

Pinout & Package

24FC256T-I/OT uses the 5-lead SOT-23 package (3.0 mm × 1.7 mm × 1.3 mm), optimized for high-density PCB layouts. Chip address pins A0, A1, and A2 are not available in this variant; device addressing defaults to fixed 000 binary (7-bit client address = 0x50 for write, 0x51 for read).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24FC256T-I/OT, the 24AA256T-I/OT trades 2.5× lower I²C bandwidth for identical package and voltage flexibility, while the AT24C256-SSH-T offers matching speed but sacrifices low-voltage operation and requires SOIC-8 layout revision-making 24FC256T-I/OT optimal for new 1.8V–5V compact designs demanding maximum throughput.

Availability

24FC256T-I/OT is available at Aetrix Electronics and suitable for smart metering, industrial PLC configuration, automotive body control, and medical diagnostic equipment requiring stable component supply across extended product lifecycles.

Supply support for 24FC256T-I/OT 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 global semiconductor company specializing in microcontrollers, analog devices, and memory solutions for industrial, automotive, and consumer markets.

The 24FC256T-I/OT belongs to Microchip's 24XX256 family of I²C EEPROMs, designed specifically for robust, low-power nonvolatile data storage in space-constrained embedded systems requiring high-speed configuration access and long-term reliability.

FAQ

What is the maximum I²C clock frequency supported by the 24FC256T-I/OT?

The 24FC256T-I/OT supports up to 1 MHz I²C clock frequency when VCC is 2.5V or higher. At VCC < 2.5V, maximum clock frequency drops to 400 kHz. This dual-speed capability ensures interoperability with both legacy and high-performance microcontrollers while maintaining full 1.7V–5.5V supply flexibility. The 24FC256T-I/OT datasheet specifies THIGH and TLOW timing constraints explicitly for 1 MHz operation.

Does the 24FC256T-I/OT have hardware write protection?

Yes, the 24FC256T-I/OT includes a dedicated Write-Protect (WP) pin (Pin 5). When WP is tied to VCC, the entire 256-Kbit memory array (addresses 0x0000–0x7FFF) is locked against write and erase operations, though read access remains fully functional. This hardware-level protection prevents accidental or malicious firmware corruption during system operation or field updates. The 24FC256T-I/OT samples WP at the Stop bit of each write command.

What package type is used for the 24FC256T-I/OT?

The 24FC256T-I/OT uses the 5-lead SOT-23 package (3.0 mm × 1.7 mm × 1.3 mm), making it one of the smallest surface-mount EEPROM options in the 24XX256 family. Unlike SOIC, MSOP, or TSSOP variants, the SOT-23 version omits chip-select pins A0–A2, fixing the I²C client address to 0x50 (write) / 0x51 (read). This simplifies routing in ultra-compact PCBs such as wearable sensors and IoT edge nodes.

How many write/erase cycles does the 24FC256T-I/OT guarantee?

The 24FC256T-I/OT guarantees a minimum of 1,000,000 write/erase cycles per memory location under standard conditions (+25°C, VCC = 5.5V, page-mode writes). This endurance rating is validated per JEDEC standards and applies across the full industrial temperature range (–40°C to +85°C). Endurance is specified per page due to internal refresh behavior during partial-page writes, as documented in the 24FC256T-I/OT datasheet Section 6.3.

Is the 24FC256T-I/OT compatible with standard I²C protocols?

Yes, the 24FC256T-I/OT is fully compliant with the Philips I²C-bus specification, supporting standard, fast, and fast-plus modes (up to 1 MHz). It implements mandatory features including Start/Stop condition detection, 7-bit addressing with R/W bit, ACK/NACK handshaking, and clock stretching avoidance. The 24FC256T-I/OT also includes Schmitt-trigger inputs and slope-controlled outputs to ensure robust bus operation in electrically noisy environments.