Microchip Technology 24FC256T-I/MF

Overview

24FC256T-I/MF from Microchip Technology is a 256-Kbit (32K × 8) I²C-compatible serial EEPROM with 1.7V–5.5V single-supply operation, 1 MHz maximum clock frequency at V_CC ≥ 2.5V, and industrial temperature range (–40°C to +85°C). It features a 64-byte page write buffer, hardware write-protection via WP pin, and Schmitt-trigger inputs for noise immunity - deployed in embedded system configuration storage, sensor calibration data retention, and power-fail-safe parameter logging.

For engineers reviewing the 24FC256T-I/MF datasheet, 24FC256T-I/MF pinout, 24FC256T-I/MF application, or 24FC256T-I/MF equivalent, key selection criteria include its 1 MHz I²C speed capability (vs. 400 kHz for 24AA256/24LC256), low 1 µA standby current, 5 ms max page write time, and MF package (8-lead DFN) footprint compatibility with space-constrained PCB layouts.

Technical Context

The 24FC256T-I/MF implements a two-wire I²C interface with programmable device addressing via A0–A2 pins, 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.

It uses Schmitt-trigger inputs on SDA/SCL for robust noise suppression and slope-controlled outputs to minimize ground bounce. Write protection is implemented via dedicated WP pin sampled at Stop condition, and ACK polling is supported to detect write cycle completion without fixed delays.

Key Specifications

Pinout & Package

24FC256T-I/MF is packaged in an 8-lead DFN (MF) with exposed thermal pad (optional V_SS connection). Pin numbering follows standard DFN orientation (pin 1 = top-left corner, counterclockwise).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA256T-I/MF and AT24C256-SSHL-T, the 24FC256T-I/MF uniquely delivers 1 MHz I²C speed *with* AEC-Q100 qualification and 1 million write cycles - making it the only option for automotive or industrial designs requiring both high throughput and long-term reliability under stress.

Availability

24FC256T-I/MF is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, and smart energy metering requiring stable component supply across extended product lifecycles.

Supply support for 24FC256T-I/MF 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, and communications markets with vertically integrated silicon and tools.

The 24FC256 belongs to Microchip's 24XX256 family of I²C EEPROMs designed specifically for low-power, high-reliability nonvolatile data storage in resource-constrained embedded systems.

FAQ

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

The 24FC256T-I/MF supports up to 1 MHz I²C clock frequency when V_CC is 2.5V or higher. At V_CC < 2.5V, the maximum clock rate drops to 400 kHz. This dual-speed capability ensures compatibility with both legacy 400 kHz systems and modern high-throughput designs - a key differentiator from the 24AA256T-I/MF and 24LC256T-I/MF variants.

Does the 24FC256T-I/MF require external pull-up resistors on the I²C bus lines?

Yes, the 24FC256T-I/MF requires external pull-up resistors on both SDA and SCL lines because its I/O pins are open-drain. Recommended values are 2 kΩ for 1 MHz operation and 10 kΩ for 100 kHz - selected based on bus capacitance and rise-time requirements specified in the datasheet. The 24FC256T-I/MF itself does not integrate pull-ups.

How does hardware write-protection work on the 24FC256T-I/MF?

Hardware write-protection on the 24FC256T-I/MF is controlled by the WP pin: when tied to V_CC, all write operations (byte and page) are inhibited while reads remain fully functional. The WP state is sampled only at the Stop condition of each write command - ensuring atomic protection that cannot be overridden mid-transaction. This behavior is identical across all 24XX256 variants.

What package type does the 24FC256T-I/MF use, and what are its key mechanical features?

The 24FC256T-I/MF uses the MF package: an 8-lead DFN (Dual Flat No-lead) measuring 2 mm × 3 mm with 0.5 mm pitch and an exposed thermal pad. The pad may be connected to V_SS for improved thermal performance or left floating. This compact footprint is ideal for space-constrained PCBs in wearables and IoT endpoints - distinct from SOIC, TSSOP, or MSOP variants in the same family.

Can the 24FC256T-I/MF be used in automotive applications?

The 24FC256T-I/MF is rated for Industrial temperature range (–40°C to +85°C) and is not AEC-Q100 qualified. While it shares the same die as AEC-Q100-qualified versions (e.g., 24FC256T-E/MF), the I-temp. variant lacks automotive qualification documentation and screening. For automotive body control or infotainment modules, the E-temp. version with AEC-Q100 certification must be selected instead of the 24FC256T-I/MF.