Microchip Technology 24FC256T-I/SM

Overview

24FC256T-I/SM from Microchip Technology is a 256-Kbit I²C serial EEPROM with 32K × 8 organization, supporting 1.7V–5.5V supply and 1 MHz clock (at V_CC ≥ 2.5V). It features 64-byte page write buffer, hardware write-protect (WP), Schmitt-trigger inputs, and operates across industrial temperature range (–40°C to +85°C) in 8-lead SOIJ package. Used for nonvolatile parameter storage in embedded controllers and sensor calibration systems.

For engineers reviewing the 24FC256T-I/SM datasheet, 24FC256T-I/SM pinout, 24FC256T-I/SM application, or 24FC256T-I/SM equivalent, key selection criteria include I²C speed compatibility (1 MHz at 2.5–5.5V), low-voltage operation down to 1.7V, page write timing (≤5 ms), WP pin behavior, and SOIJ package footprint for space-constrained PCBs.

Technical Context

The 24FC256T-I/SM implements a two-wire I²C-compatible interface with dedicated SDA (open-drain bidirectional data) and SCL (input clock) pins, plus hardware write-protection via the WP pin. Its internal address counter supports current-address, random, and sequential reads across the full 0000h–7FFFh memory map.

It uses on-chip charge-pump high-voltage generation for EEPROM programming, enabling self-timed erase/write cycles without external V_PP. The device incorporates Schmitt-trigger inputs on SDA/SCL and output slope control to suppress ground bounce and improve noise immunity in noisy industrial environments.

Key Specifications

Pinout & Package

24FC256T-I/SM is packaged in an 8-lead SOIJ (Small Outline J-Lead) surface-mount package, 5.28 mm wide, with gull-wing leads suitable for automated assembly and reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA256T-I/SM, the 24FC256T-I/SM delivers higher throughput via 1 MHz I²C, while AT24C256-10PU-2.7 trades voltage flexibility for legacy packaging - making 24FC256T-I/SM optimal for modern low-voltage, high-speed embedded designs requiring SOIJ footprint.

Availability

24FC256T-I/SM is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration, automotive body control modules, and smart energy meters requiring stable component supply, long-term data retention, and AEC-Q100-aligned reliability.

Supply support for 24FC256T-I/SM 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 microcontrollers, analog, FPGA, and memory solutions, serving industrial, automotive, and consumer markets with vertically integrated design and manufacturing.

The 24FC256 belongs to Microchip's 24XX256 family of I²C EEPROMs, engineered for low-power, high-reliability nonvolatile storage in resource-constrained embedded systems where voltage flexibility and noise immunity are critical.

FAQ

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

The 24FC256T-I/SM supports up to 1 MHz I²C clock frequency when V_CC is 2.5V or higher. At V_CC < 2.5V, maximum clock frequency drops to 400 kHz. This dual-speed capability allows the 24FC256T-I/SM to operate efficiently across both 1.8V and 3.3V systems without sacrificing performance where voltage permits.

How does the WP pin function on the 24FC256T-I/SM?

The WP (Write-Protect) pin on the 24FC256T-I/SM is an active-high input: when tied to V_CC, it disables all write operations (including byte and page writes) while permitting unrestricted reads. When tied to V_SS, full read/write access is enabled. The pin is sampled at the Stop condition of each write command, ensuring reliable protection even during partial bus transactions.

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

The 24FC256T-I/SM uses an 8-lead SOIJ (Small Outline J-Lead) package, 5.28 mm wide, with gull-wing leads optimized for surface-mount reflow assembly. This package matches the footprint of standard SOIC-8 but offers improved thermal dissipation and mechanical stability in vibration-prone environments.

Can multiple 24FC256T-I/SM devices share the same I²C bus?

Yes - up to eight 24FC256T-I/SM devices can be cascaded on a single I²C bus using hardware-configurable A0, A1, and A2 address pins. Each device is assigned a unique 3-bit chip address (1010xxx0), allowing independent addressing without software arbitration. The SOIJ package supports this via fully bonded A0–A2 pins.

What is the page write buffer size of the 24FC256T-I/SM?

The 24FC256T-I/SM features a 64-byte page write buffer, enabling up to 64 bytes of data to be loaded into the on-chip latch before initiating the internal write cycle. This reduces I²C transaction overhead significantly versus byte-write mode and improves effective write throughput, especially for structured configuration data.