Microchip Technology 24LC256-E/ST16KVAO

Overview

24LC256-E/ST16KVAO 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 with low-power I²C interface.

For engineers reviewing the 24LC256-E/ST16KVAO datasheet, 24LC256-E/ST16KVAO pinout, 24LC256-E/ST16KVAO application, or 24LC256-E/ST16KVAO equivalent, key selection considerations include VCC min/max compliance (2.5V–5.5V), 400 kHz I²C timing at full voltage, industrial-grade temperature operation, SOIC-8 package footprint, and hardware write-protect functionality.

Technical Context

The 24LC256-E/ST16KVAO implements a two-wire I²C-compatible interface with open-drain SDA/SCL pins requiring external pull-ups. Its internal address counter 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), enabling up to eight devices on one bus.

Write operations are self-timed and internally managed: byte writes complete in ≤5 ms; page writes (up to 64 bytes within a single 64-byte physical page boundary) also require ≤5 ms. The WP pin is sampled at the Stop bit of each write command to enable or disable array programming - no effect if toggled mid-cycle.

Key Specifications

Pinout & Package

24LC256-E/ST16KVAO is supplied in an 8-lead SOIC (Small Outline Integrated Circuit) package with 150-mil body width and standard 1.27 mm pitch. Pin 1 is marked by a beveled corner or notch; orientation follows JEDEC MS-012AA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA256-I/ST and AT24C256-10PU-2.7, the 24LC256-E/ST16KVAO provides guaranteed 2.5V operation, industrial temperature validation, and Microchip's enhanced noise immunity - making it optimal for robust embedded systems where voltage margin and EMI resilience are critical.

Availability

24LC256-E/ST16KVAO is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, and automotive body control modules requiring stable component supply with long-term lifecycle support.

Supply support for 24LC256-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 leading provider of microcontrollers, analog, FPGA, and memory solutions, serving automotive, industrial, consumer, and communications markets with vertically integrated silicon and software platforms.

The 24LC256 belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power, I²C-based nonvolatile data storage in resource-constrained embedded systems requiring long-term data integrity.

FAQ

What is the minimum operating voltage for the 24LC256-E/ST16KVAO?

The 24LC256-E/ST16KVAO operates down to 2.5V - unlike the 24AA256 variant which supports 1.7V. This makes it suitable for 3.3V systems but not for sub-2.5V battery-powered designs. Operation below 2.5V may result in unreliable writes or communication failures, as confirmed by Microchip's DS20001203Y electrical specifications.

Does the 24LC256-E/ST16KVAO support 1 MHz I²C operation?

No, the 24LC256-E/ST16KVAO supports up to 400 kHz I²C clock frequency at VCC ≥ 2.5V. Only the 24FC256 variant in the same family supports 1 MHz. Attempting 1 MHz operation on the 24LC256-E/ST16KVAO will violate AC timing parameters including THIGH, TLOW, and TSU:DAT, causing communication errors.

How many devices can be connected on the same I²C bus using the 24LC256-E/ST16KVAO?

Up to eight 24LC256-E/ST16KVAO devices can share one I²C bus using unique combinations of A0, A1, and A2 address pins. Each pin must be hardwired to VSS or VCC to set a distinct 3-bit chip address (1010xxx0), enabling a total addressable space of 2 Mbit across the bus.

What happens when the WP pin is tied high on the 24LC256-E/ST16KVAO?

When WP is tied to VCC, all write and erase operations to the EEPROM array are inhibited - reads continue normally. The device acknowledges write commands but performs no internal programming. This hardware-level protection prevents accidental overwrites during power transitions or firmware faults, and is sampled only at the Stop condition of each command.

Is the 24LC256-E/ST16KVAO RoHS compliant and AEC-Q100 qualified?

Yes, the 24LC256-E/ST16KVAO is RoHS compliant and AEC-Q100 qualified for automotive applications. Per Microchip's DS20001203Y documentation, it meets Grade 2 (–40°C to +105°C) and Grade 3 (–40°C to +125°C) stress testing - though the -E suffix denotes Industrial (–40°C to +85°C) grade, its underlying qualification supports automotive deployment.