Microchip Technology 24LC256-I/MS

Overview

24LC256-I/MS from Microchip Technology is a 256-Kbit I²C-compatible serial EEPROM in an 8-lead MSOP package, operating from 2.5V to 5.5V with 400 kHz max clock frequency and industrial temperature range (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protection via WP pin, and >1 million erase/write cycles - deployed in embedded systems for parameter storage, calibration data retention, and firmware configuration.

For engineers reviewing the 24LC256-I/MS datasheet, 24LC256-I/MS pinout, 24LC256-I/MS application, or 24LC256-I/MS equivalent, key selection criteria include VCC min/max compliance, I²C timing at 400 kHz, WP pin behavior during write cycles, and MSOP package footprint compatibility with space-constrained PCB layouts.

Technical Context

The 24LC256-I/MS implements a two-wire I²C interface with Schmitt-trigger inputs on SDA/SCL for noise immunity and slope-controlled outputs to suppress ground bounce. Its internal address pointer supports sequential reads across the full 32K × 8 memory array, with automatic rollover from address 7FFFh to 0000h.

Unlike the 24AA256 and 24FC256 variants, the 24LC256-I/MS requires minimum VCC = 2.5V and supports only up to 400 kHz clock frequency - not 1 MHz - and uses A2 as the sole chip-select bit in MSOP packages (A0/A1 are no-connects), limiting bus scalability to two devices.

Key Specifications

Pinout & Package

8-lead MSOP (Micro Small Outline Package), 3.0 mm × 3.0 mm body, 0.65 mm pitch, exposed pad optional (not electrically connected). Pin 1 marked by bevelled corner or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC256-I/MS, the 24AA256-I/MS extends voltage range downward for ultra-low-power operation, while the AT24C256-MAHM-T trades broader vendor support for higher speed and endurance - both require no PCB changes but demand validation of timing and qualification alignment.

Availability

24LC256-I/MS is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, medical diagnostic equipment, and smart energy meters requiring stable component supply across extended production lifecycles.

Supply support for 24LC256-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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and memory solutions for embedded control applications.

The 24LC256 belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power nonvolatile data storage in space- and cost-constrained industrial and automotive systems.

FAQ

What is the minimum supply voltage required for reliable operation of the 24LC256-I/MS?

The 24LC256-I/MS requires a minimum VCC of 2.5V for guaranteed functionality across its specified industrial temperature range. Operation below 2.5V may result in incomplete writes, read errors, or failure to acknowledge I²C commands - unlike the 24AA256 variant, which supports down to 1.7V. Always verify VCC stability during brownout conditions in your design.

Does the 24LC256-I/MS support 1 MHz I²C communication?

No, the 24LC256-I/MS supports a maximum I²C clock frequency of 400 kHz. The 24FC256 variant supports 1 MHz, but the 24LC256-I/MS is explicitly rated for 400 kHz only - attempting 1 MHz operation will violate setup/hold timing and cause communication failures. Use the AC characteristics table (DS20001203Y, page 4) to validate timing margins at your target clock rate.

How many devices can be connected on the same I²C bus using the 24LC256-I/MS in MSOP package?

Only two 24LC256-I/MS devices can share the same I²C bus when using the MSOP package, because pins A0 and A1 are not connected - only A2 is functional for chip addressing. This limits the device address space to two combinations (1010000 and 1010001), unlike SOIC or TSSOP packages that support up to eight devices via A2/A1/A0.

What happens when the WP pin is held high during a write command to the 24LC256-I/MS?

When the WP pin is tied to VCC, the 24LC256-I/MS acknowledges the write command but performs no memory programming - data remains unchanged, and the internal write cycle does not initiate. The device immediately accepts subsequent commands, enabling safe command stream execution without risk of unintended writes during initialization or fault recovery.

Is the 24LC256-I/MS qualified for automotive applications under AEC-Q100?

No, the 24LC256-I/MS carries the "I" (Industrial) temperature grade (–40°C to +85°C) and is not AEC-Q100 qualified. For automotive use, Microchip offers the 24LC256-E/MS (Extended temp, –40°C to +125°C) or AEC-Q100 qualified variants like the 24AA256-E/MNY - always verify qualification status in the official Microchip part marking and packaging documentation.