Microchip Technology 24LC256T-I/MF

Overview

24LC256T-I/MF from Microchip Technology is a 256-Kbit I²C serial EEPROM with 32K × 8 organization, operating from 2.5V to 5.5V, supporting up to 400 kHz clock frequency, and rated for industrial temperature range (−40°C to +85°C). It features hardware write-protection via the WP pin, 64-byte page write buffer, and Schmitt-trigger inputs for noise immunity - deployed in embedded systems requiring nonvolatile parameter storage.

For engineers reviewing the 24LC256T-I/MF datasheet, 24LC256T-I/MF pinout, 24LC256T-I/MF application, or 24LC256T-I/MF equivalent, key selection criteria include VCC min/max compliance, I²C timing at target bus speed, page write capability, WP pin behavior, and package footprint compatibility with 8-lead MSOP (MF).

Technical Context

The 24LC256T-I/MF implements a two-wire I²C-compatible interface with open-drain SDA/SCL pins requiring external pull-ups. Its internal address pointer supports current-address, random, and sequential reads across the full 0000h–7FFFh memory space. Device addressing uses a fixed 4-bit control code (1010b) plus three user-configurable chip-select bits (A2/A1/A0), though A0 and A1 are not connected in the MF package.

Write operations are self-timed: byte writes complete in ≤5 ms, and page writes (up to 64 bytes within a single 64-byte-aligned physical page) also require ≤5 ms. During active write cycles, the device does not acknowledge I²C commands - enabling reliable ACK polling for host synchronization without fixed delay timers.

Key Specifications

Pinout & Package

24LC256T-I/MF is packaged in an 8-lead MSOP (MF) with exposed pad. Pin 1 is marked by a beveled corner; A0 and A1 are not connected (NC) per datasheet Note on page 7. The package is lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC256T-I/MF, the 24AA256-I/MF offers broader supply voltage support but identical functionality and package; the AT24C256-MAHM-T provides functional equivalence in SOIC but lacks automotive qualification and requires mechanical redesign.

Availability

24LC256T-I/MF is available at Aetrix Electronics and suitable for smart energy metering, industrial PLC configuration, and automotive body control modules requiring stable component supply, long-term data retention, and industrial-temperature reliability.

Supply support for 24LC256T-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 microcontrollers, analog components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24LC256T-I/MF belongs to Microchip's 24XX256 family of I²C serial EEPROMs, designed specifically for low-power, space-constrained embedded systems needing reliable nonvolatile storage with simple two-wire interface integration.

FAQ

What is the minimum supply voltage required for 24LC256T-I/MF operation?

The 24LC256T-I/MF requires a minimum VCC of 2.5V, as specified in the Device Selection Table on page 1 of DS20001203Y. Unlike the 24AA256 variant, it is not rated for operation below 2.5V - attempting to power it at 1.8V or 2.3V will result in undefined behavior or failure to respond on the I²C bus. Always verify VCC stability within 2.5V–5.5V during system power-up and brownout conditions.

Does 24LC256T-I/MF support page writes across memory boundaries?

No, the 24LC256T-I/MF does not support page writes across physical page boundaries. Each page is 64 bytes wide, aligned to addresses 0000h, 0040h, 0080h, etc. If a page write command attempts to write past the end of the current page (e.g., starting at 003Fh with 64 bytes), data wraps to the start of the same page instead of advancing to the next. Application firmware must enforce boundary checks before initiating page writes to prevent unintended overwrites.

How does the WP pin function on 24LC256T-I/MF?

The WP (Write-Protect) pin on 24LC256T-I/MF is sampled at the STOP bit of every I²C write command. When tied to VCC, it inhibits all write operations (byte and page) while allowing unrestricted reads. When tied to VSS (or left floating with pull-down), writes are enabled. WP has no effect on read cycles, and its state cannot be changed mid-write - toggling WP after STOP has no impact on an ongoing internal write cycle.

Can multiple 24LC256T-I/MF devices share the same I²C bus?

Yes, up to two 24LC256T-I/MF devices can share the same I²C bus when using the MF (MSOP) package, because A0 and A1 are not connected - only A2 is used for chip select. This yields two possible client addresses: 1010 0 0 0 R/W and 1010 1 0 0 R/W. For more than two devices, a different package (e.g., SOIC with A0/A1/A2 accessible) or alternate part number (e.g., 24AA256) is required.

What is the maximum write endurance specification for 24LC256T-I/MF?

The 24LC256T-I/MF is rated for 1,000,000 erase/write cycles per memory page (not per byte), as confirmed in Table 1-2, Parameter 18 of DS20001203Y. This endurance applies under +25°C and 5.5V conditions using page-mode writes. Real-world endurance may vary with temperature, voltage, and pattern - but the 1M-cycle guarantee ensures robustness for applications involving daily configuration updates over 10+ years.