Microchip Technology 24LC256T-E/ST16KVAO

Overview

24LC256T-E/ST16KVAO from Microchip Technology is a 256-Kbit (32K × 8) I²C-compatible serial EEPROM with hardware write-protection, 64-byte page write buffer, and operation across 2.5V–5.5V supply. It supports up to eight devices on one bus via A0–A2 address pins, features Schmitt-trigger inputs for noise immunity, and delivers 400 kHz clock frequency at V_CC ≥ 2.5V. It is used in industrial sensor calibration storage and embedded system configuration retention.

For engineers reviewing the 24LC256T-E/ST16KVAO datasheet, 24LC256T-E/ST16KVAO pinout, 24LC256T-E/ST16KVAO application, or 24LC256T-E/ST16KVAO equivalent, this page provides verified electrical specs, package mapping to 8-lead SOIC, confirmed I²C timing compliance, endurance (1M cycles), and real-world use cases in automotive-grade data logging and power-meter firmware storage.

Technical Context

The 24LC256T-E/ST16KVAO implements a two-wire I²C interface with open-drain SDA/SCL requiring external pull-ups, and uses internal address pointer logic for sequential reads across the full 0000h–7FFFh memory space. Its write-protection is controlled solely by the WP pin state at Stop condition sampling - no software lock or register-based protection is present.

It employs a self-timed erase/write cycle with 5 ms maximum page write time, and supports byte and page write modes. The device uses Schmitt-trigger inputs on SDA/SCL (hysteresis ≥ 0.05 V_CC) and slope control to suppress ground bounce, meeting I²C standard timing requirements for THD:STA, TSU:DAT, and TAA at both 100 kHz and 400 kHz.

Key Specifications

Pinout & Package

24LC256T-E/ST16KVAO is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with standard 1.27 mm pitch and JEDEC MS-012AC footprint. Pin 1 is marked with a beveled corner or dot; pin numbering follows counter-clockwise convention from pin 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC256T-E/ST16KVAO, the 24AA256-I/SN offers broader supply flexibility but sacrifices extended temperature capability, while the AT24C256-10PU-2.7 delivers faster write cycles at the cost of tighter timing constraints and different vendor-specific ACK behavior - both require PCB layout reuse but firmware validation.

Availability

24LC256T-E/ST16KVAO is available at Aetrix Electronics and suitable for industrial sensor calibration storage, automotive ECU configuration retention, and smart energy meter firmware parameters requiring stable component supply across multi-year production cycles.

Supply support for 24LC256T-E/ST16KVAO 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 nonvolatile memory solutions for industrial, automotive, and consumer markets.

The 24LC256T-E/ST16KVAO belongs to Microchip's 24XX256 family of I²C EEPROMs, designed specifically for robust, low-power, multi-device configuration storage in harsh environments with guaranteed data integrity and long-term reliability.

FAQ

What is the maximum I²C clock frequency supported by the 24LC256T-E/ST16KVAO?

The 24LC256T-E/ST16KVAO supports up to 400 kHz I²C clock frequency when V_CC is 2.5V or higher. At voltages below 2.5V, the maximum clock rate drops to 100 kHz. This specification is confirmed in Table 1-2 of the DS20001203Y datasheet and applies directly to the 24LC256 variant, including the 24LC256T-E/ST16KVAO part number.

Does the 24LC256T-E/ST16KVAO support page write operations, and what is the buffer size?

Yes, the 24LC256T-E/ST16KVAO supports page write operations with a 64-byte page buffer. This allows up to 64 bytes to be loaded into the internal latch before initiating the self-timed write cycle. Page boundaries align to 64-byte intervals (e.g., 0000h–003Fh), and crossing a boundary causes wraparound within the same page - a constraint explicitly documented for the 24LC256T-E/ST16KVAO in Section 6.3 of the datasheet.

How does the Write-Protect (WP) pin function on the 24LC256T-E/ST16KVAO?

The WP pin on the 24LC256T-E/ST16KVAO is sampled at the Stop condition of each write command. When tied to VCC, it disables all write operations (including byte and page writes) while permitting unlimited reads. When tied to VSS, full read/write access is enabled. This hardware-level protection requires no firmware intervention and is validated for the 24LC256T-E/ST16KVAO in Section 6.3 and Figure 1-1 of the official datasheet.

What temperature range is guaranteed for the 24LC256T-E/ST16KVAO?

The 24LC256T-E/ST16KVAO is rated for the Extended temperature range of −40°C to +125°C, as indicated by the "E" suffix in the part number and confirmed in the Device Selection Table on page 1 of DS20001203Y. This qualification includes AEC-Q100 stress testing, making it suitable for under-hood automotive and high-ambient industrial applications.

Is the 24LC256T-E/ST16KVAO pin-compatible with other 24XX256 family members in SOIC-8 packaging?

Yes, the 24LC256T-E/ST16KVAO shares identical pinout and SOIC-8 footprint with all 24XX256 variants in that package, including 24AA256 and 24FC256. Pin functions (A0–A2, SDA, SCL, WP, VSS, VCC) are electrically and physically identical, enabling direct substitution in designs using the same package - though voltage range and clock speed differences must be verified per application.