Microchip Technology 24FC256-I/SM

Overview

24FC256-I/SM from Microchip Technology is a 256-Kbit (32K × 8) I²C-compatible serial EEPROM with 1.7V–5.5V 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 firmware parameter backup.

For engineers reviewing the 24FC256-I/SM datasheet, 24FC256-I/SM pinout, 24FC256-I/SM application, or 24FC256-I/SM equivalent, key selection criteria include its 1 MHz I²C speed capability, 1 µA standby current, 5 ms max page write time, and compatibility with cascaded multi-device bus topologies up to eight units.

Technical Context

The 24FC256-I/SM implements a two-wire I²C interface with open-drain SDA/SCL lines requiring external pull-ups, supporting standard (100 kHz), fast (400 kHz), and fast-plus (1 MHz) modes depending on V_CC. Its internal address counter enables sequential reads across the full 0000h–7FFFh memory space, while hardware write-protection is controlled solely by the WP pin state at Stop bit sampling.

It uses a self-timed erase/write cycle with on-chip charge pump, supports byte and page writes (up to 64 bytes within a single physical page boundary), and incorporates input hysteresis (≥0.05 V_CC) and output slope control to suppress ground bounce and EMI - critical for noisy industrial environments.

Key Specifications

Pinout & Package

24FC256-I/SM is supplied in an 8-lead SOIJ (Small Outline J-Lead) package with gull-wing leads, 5.28 mm body width, and JEDEC MS-012AC compliant footprint. Pin 1 is marked with a notch or dot; pin numbering follows standard SOIC/SOIJ convention (counterclockwise from notch).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA256-I/SM and AT24C256-10PU-2.7, the 24FC256-I/SM uniquely delivers 1 MHz I²C performance across the full 1.7–5.5V range and automotive qualification - making it optimal for next-generation low-power, high-reliability embedded systems requiring rapid configuration writes.

Availability

24FC256-I/SM is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 24FC256-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 components, 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 specifically for low-voltage, high-speed configuration storage in resource-constrained embedded systems demanding robustness and long-term data integrity.

FAQ

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

The 24FC256-I/SM 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 seamless integration across both legacy and high-performance I²C systems without redesign. The 24FC256-I/SM datasheet specifies timing parameters like THIGH and TLOW explicitly for both conditions.

Does the 24FC256-I/SM require an external high-voltage programming supply?

No, the 24FC256-I/SM does not require an external high-voltage supply. It uses an internal charge pump to generate the necessary programming voltage from the standard 1.7–5.5V V_CC rail. All write operations - including byte and page writes - are executed using only the main supply, simplifying board design and eliminating need for VPP circuitry or level translators.

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

Hardware write-protection on the 24FC256-I/SM is controlled exclusively by the WP (Write-Protect) pin. When WP is tied to V_CC, all write operations (byte, page, and erase) are inhibited - though read operations remain fully functional. The pin state is sampled only at the Stop condition of each write command, ensuring reliable lockout even during power transients. This behavior is confirmed in the DS20001203Y datasheet Section 6.3.

Can multiple 24FC256-I/SM devices share the same I²C bus?

Yes, up to eight 24FC256-I/SM devices can be cascaded on a single I²C bus using the A0, A1, and A2 address pins to configure unique 3-bit chip addresses. Each device responds only to its assigned address (1010+A2A1A0), enabling expansion of total addressable memory to 2 Mbit. The SOIJ package used in 24FC256-I/SM fully supports all three address pins, unlike MSOP or SOT-23 variants.

What is the page size and maximum page write length for the 24FC256-I/SM?

The 24FC256-I/SM has a fixed 64-byte page size and supports page writes of up to 64 bytes in a single transaction. Writes crossing physical page boundaries (e.g., starting at address 0x003F) wrap around to the beginning of the same page rather than advancing to the next - a behavior documented in Section 6.2 of the datasheet. Firmware must align page writes to 64-byte boundaries (0x0000, 0x0040, etc.) to avoid unintended data overwrite.