Microchip Technology 24LC256T-E/SN

Overview

24LC256T-E/SN 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 64-byte page write buffer, hardware write-protect (WP pin), and Schmitt-trigger inputs for noise immunity - deployed in embedded system configuration storage, sensor calibration data retention, and power-fail-safe parameter logging.

For engineers reviewing the 24LC256T-E/SN datasheet, 24LC256T-E/SN pinout, 24LC256T-E/SN application, or 24LC256T-E/SN equivalent, key selection considerations include VCC min/max compliance (2.5–5.5V), I²C timing at 400 kHz, WP-enabled hardware protection, 1 µA standby current, and SOIC-8 package compatibility with legacy board layouts.

Technical Context

The 24LC256T-E/SN implements a two-wire I²C-compatible interface with open-drain SDA/SCL requiring external pull-ups, and uses internal address pointer logic to support current-address, random, and sequential reads across its full 0000h–7FFFh memory map. Its cascading architecture allows up to eight devices on one bus via A0/A1/A2 address pins.

Write operations are self-timed with maximum 5 ms byte/page cycle duration; page writes buffer up to 64 bytes before initiating erase/write, while acknowledge polling enables host-driven completion detection without fixed delays. The WP pin samples at the Stop bit to enable/disable writes independently of read access.

Key Specifications

Pinout & Package

24LC256T-E/SN is supplied in an 8-lead SOIC (Small Outline Integrated Circuit) package with standard 150-mil body width and gull-wing leads. Pin 1 is marked by a beveled corner or notch; orientation follows JEDEC MS-012.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA256-I/SN and AT24C256-10PU-2.7, the 24LC256T-E/SN offers optimal balance of industrial temperature rating, 1-million-cycle endurance, and guaranteed 400 kHz performance at 2.5V - making it the preferred choice for mission-critical embedded systems where reliability trumps ultra-low-voltage operation or raw speed.

Availability

24LC256T-E/SN 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 sourcing.

Supply support for 24LC256T-E/SN 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 microcontroller, analog, FPGA, and memory solutions, serving industrial, automotive, communications, and consumer markets with vertically integrated silicon and development tools.

The 24LC256T-E/SN belongs to Microchip's 24XX256 family of I²C EEPROMs, designed specifically for low-power, high-reliability nonvolatile data storage in embedded systems where firmware simplicity, bus efficiency, and long-term data integrity are essential.

FAQ

What is the minimum supply voltage required for reliable operation of the 24LC256T-E/SN?

The 24LC256T-E/SN requires a minimum VCC of 2.5V for guaranteed operation across its full temperature range (–40°C to +85°C). Unlike the 24AA256 variant, it is not specified for operation below 2.5V - attempting to power it at 1.8V or 2.2V may result in unpredictable read/write behavior or failure to acknowledge I²C commands.

Does the 24LC256T-E/SN support page write operations, and what is the maximum buffer size?

Yes, the 24LC256T-E/SN supports page write operations with a 64-byte internal buffer. This allows up to 64 data bytes to be loaded into the buffer before issuing a Stop condition, after which the device performs a single self-timed write cycle - significantly improving throughput compared to individual byte writes.

How does the Write-Protect (WP) pin function on the 24LC256T-E/SN?

The WP pin on the 24LC256T-E/SN is sampled only at the Stop bit of each write command. When tied to VCC, it disables all write operations (byte and page) while permitting unrestricted reads; when tied to VSS, writes are enabled. This design prevents partial writes during power transitions or noise glitches.

Can multiple 24LC256T-E/SN devices share the same I²C bus, and how is addressing managed?

Yes, up to eight 24LC256T-E/SN devices can share one I²C bus using the A0, A1, and A2 address pins. Each device is assigned a unique 3-bit chip address by hardwiring these pins to VSS or VCC; the host includes this address in the control byte's upper bits to select the target device.

What is the typical standby current consumption of the 24LC256T-E/SN at room temperature?

The 24LC256T-E/SN draws a maximum standby current of 1 µA under industrial temperature conditions (–40°C to +85°C) when SDA, SCL, A0–A2, and WP are held at valid logic levels and VCC = 3.6V. This ultra-low quiescent current makes it ideal for battery-powered or energy-harvesting applications requiring persistent memory with minimal drain.