Microchip Technology 24FC256-I/MS

Overview

24FC256-I/MS from Microchip Technology is a 256-Kbit I²C serial EEPROM in an 8-lead MSOP package, operating from 1.7V to 5.5V with 1 MHz I²C clock support (at V_CC ≥ 2.5V), 64-byte page write buffer, and hardware write-protection via the WP pin. It delivers 1 µA standby current and supports up to eight devices on one bus for expanded memory addressing in embedded control systems.

For engineers reviewing the 24FC256-I/MS datasheet, 24FC256-I/MS pinout, 24FC256-I/MS application, or 24FC256-I/MS equivalent, key selection criteria include its 1 MHz high-speed I²C interface at low voltage, industrial temperature range (–40°C to +85°C), MSOP package footprint compatibility, and page-write endurance of 1 million cycles.

Technical Context

The 24FC256-I/MS implements a two-wire I²C-compatible interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. Its internal address pointer enables sequential, random, and current-address read modes across the full 32K × 8 memory array.

Write operations are self-timed and support byte or page writes (up to 64 bytes per page); the WP pin provides hardware-level protection of the entire 256-Kbit array. Acknowledge polling allows host firmware to detect write completion without fixed delay timing.

Key Specifications

Pinout & Package

24FC256-I/MS uses an 8-lead MSOP (Mini Small Outline Package) with 3.0 mm × 3.0 mm body and 0.65 mm lead pitch. Pins A0 and A1 are not connected in this package variant; only A2, SDA, SCL, WP, VCC, and VSS are functional.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA256-I/MS, the 24FC256-I/MS delivers 2.5× faster I²C writes without layout changes; versus AT24C256-MAHM-T, it adds AEC-Q100 qualification and lower standby current-critical for battery-powered automotive modules.

Availability

24FC256-I/MS is available at Aetrix Electronics and suitable for smart metering, automotive body control, and industrial PLC I/O modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for 24FC256-I/MS 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 automotive, industrial, and communications markets with vertically integrated silicon and tools.

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

FAQ

What is the maximum I²C clock frequency supported by the 24FC256-I/MS?

The 24FC256-I/MS 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 allows flexible integration across 1.8V, 3.3V, and 5V systems while maintaining optimal performance within each voltage domain. The 24FC256-I/MS datasheet specifies timing parameters including THIGH, TLOW, and TAA for both conditions.

Does the 24FC256-I/MS require external pull-up resistors on SDA and SCL lines?

Yes, the 24FC256-I/MS requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. Typical values are 2 kΩ for 1 MHz operation and 10 kΩ for 100 kHz. The exact value depends on bus capacitance and desired rise time; the 24FC256-I/MS AC characteristics specify maximum TR/TF limits that must be met to ensure reliable communication.

How does hardware write-protection work on the 24FC256-I/MS?

Hardware write-protection on the 24FC256-I/MS is controlled by the WP pin: when tied to V_CC, all write operations (byte and page) are inhibited, though read operations remain fully functional. The pin state is sampled at the Stop condition of each write command. This feature prevents accidental or malicious overwrites during power transitions or firmware errors, and is independent of software locks.

What is the page write capability of the 24FC256-I/MS?

The 24FC256-I/MS features a 64-byte page write buffer, allowing up to 64 bytes to be written in a single I²C transaction. This reduces bus overhead and host CPU load compared to byte-wise writes. Page boundaries align to 64-byte intervals (e.g., 0x0000–0x003F), and crossing a boundary causes wraparound-so software must manage address alignment to avoid unintended overwrites.

Is the 24FC256-I/MS qualified for automotive applications?

Yes, the 24FC256-I/MS is AEC-Q100 qualified for automotive applications and rated for the industrial temperature range (–40°C to +85°C). This qualification covers stress testing for reliability under thermal cycling, humidity, and vibration-making it suitable for body control modules, infotainment systems, and other non-powertrain automotive subsystems where robust nonvolatile memory is required.