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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Microchip Technology 24AA256-E/SN

Name: 24AA256-E/SN
Brand: Microchip Technology
SKU: 24AA256-E/SN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 24AA256-E/SN

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: 24AA256-E/SN.pdf

Description:: IC EEPROM 256KBIT I2C 8SOIC

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Inventory:2,650

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Product details

Overview

24AA256-E/SN from Microchip Technology is a 256-Kbit (32K × 8) I²C-compatible serial EEPROM with 1.7V–5.5V single-supply operation, 400 kHz maximum clock frequency, and industrial temperature range (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protect (WP), Schmitt-trigger inputs, and >1 million erase/write cycles - deployed in embedded sensor calibration, power supply configuration, and industrial control firmware storage.

For engineers reviewing the 24AA256-E/SN datasheet, 24AA256-E/SN pinout, 24AA256-E/SN application, or 24AA256-E/SN equivalent, key selection criteria include low-voltage operation down to 1.7V, I²C bus compatibility up to 400 kHz, hardware write protection via dedicated WP pin, and SOIC-8 package compatibility with legacy PCB layouts.

Technical Context

The 24AA256-E/SN implements a two-wire I²C interface with open-drain SDA/SCL pins requiring external pull-ups, and uses three address pins (A0–A2) to support up to eight devices on one bus. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and memory control logic enabling byte- and page-write operations with self-timed erase/write cycles.

It supports random and sequential reads across the full 256-Kbit address space (0x0000–0x7FFF), with automatic address pointer incrementation and wraparound at boundary. Write protection is enforced by sampling the WP pin state at the Stop condition - no writes occur when WP = VCC, while reads remain fully functional.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	256 Kbit (32K × 8), providing nonvolatile storage for configuration data, calibration tables, or boot parameters without external backup power.
Supply Voltage	1.7V–5.5V - enables direct integration into ultra-low-power systems (e.g., battery-powered sensors) and compatibility with 3.3V/5V host controllers.
I²C Clock Frequency	Up to 400 kHz (at VCC ≥ 2.5V); ensures reliable communication with standard microcontrollers while maintaining noise immunity via Schmitt-trigger inputs.
Page Write Buffer	64 bytes - reduces total write time vs. byte-write mode and minimizes bus occupancy during bulk data updates (e.g., firmware patch storage).
Endurance & Retention	1,000,000 write cycles and >200 years data retention - suitable for field-deployed equipment requiring long-term reliability without maintenance.
Write Protection	Hardware-enabled via dedicated WP pin - prevents accidental overwrites during power-up/down or firmware updates without software intervention.
Operating Temperature	–40°C to +85°C (Industrial grade) - validated for use in factory automation, motor drives, and outdoor metering applications.

Pinout & Package

24AA256-E/SN is supplied in an 8-lead SOIC (Small Outline Integrated Circuit) package with 150 mil body width, surface-mount compatible footprint, and JEDEC-standard pinout. The package is RoHS-compliant and rated for industrial temperature operation.

Pin/Terminal	Circuit Role	Design Meaning
A0	Chip Address Input	User-configurable LSB of device address; hardwired to VSS or VCC to select one of eight possible I²C addresses on shared bus.
A1	Chip Address Input	Mid-bit of device address; determines unique client address alongside A0 and A2 for multi-device I²C topology.
A2	Chip Address Input	MSB of device address; enables cascading up to eight 24AA256-E/SN devices on same I²C bus for extended storage capacity.
VSS	Ground Reference	Primary return path for all internal circuitry and I/O signals; must be connected to system ground plane for stable operation.
SDA	Serial Data I/O	Open-drain bidirectional bus line; requires external pull-up resistor (e.g., 2–10 kΩ) and supports ACK/NACK signaling per I²C protocol.
SCL	Serial Clock Input	Master-generated clock signal synchronizing all data transfers; rising edge samples SDA, falling edge allows SDA transitions.
WP	Write-Protect Control	Active-high enable/disable for all write operations; tied to VCC to lock memory contents during critical runtime phases.
VCC	Power Supply	Single positive supply input (1.7–5.5V); powers EEPROM array, interface logic, and charge pump for write/erase functions.

Key Features

Feature	Design Value
Low-Voltage Operation	Functional down to 1.7V - eliminates need for level shifters in 1.8V/2.5V microcontroller systems and extends battery life in portable designs.
Noise-Immune Interface	Schmitt-trigger inputs on SDA/SCL with 50 ns spike suppression and 0.05×VCC hysteresis - rejects EMI in motor-driven or switching-power environments.
Page Write Efficiency	64-byte buffer enables single-stop bulk writes - cuts typical 256-byte update time from ~1.3s (byte mode) to ~5ms, improving system responsiveness.
Hardware Write Lock	Dedicated WP pin sampled only at Stop condition - prevents partial writes during brown-out or reset, ensuring data integrity without firmware overhead.
High Reliability	1M endurance cycles and >200-year data retention - certified for mission-critical storage in industrial PLCs, medical diagnostics, and energy meters.

Applications

Smart Energy Metering	Industrial PLC Configuration
Use Scenario: Storing tariff schedules, meter calibration constants, and tamper-event logs in utility-grade electricity meters operating unattended for 15+ years. IC Role / Device Role / Timing Role: Nonvolatile configuration register holding time-critical calibration data accessed at power-on and updated infrequently via secure I²C commands. Use Value: Eliminates need for battery-backed SRAM; leverages 200-year retention and 1M-cycle endurance to meet ANSI C12.20 and IEC 62056 compliance.	Use Scenario: Persisting I/O mapping, PID loop parameters, and safety interlock states in programmable logic controllers deployed in harsh factory environments. IC Role / Device Role / Timing Role: Field-programmable memory storing user-defined control logic variables that survive power loss and firmware upgrades. Use Value: Hardware write-protection (WP pin) prevents corruption during voltage transients common in 24V DC industrial buses.
Medical Sensor Calibration	Automotive Body Control Module
Use Scenario: Holding factory-trimmed offset/gain coefficients for analog front-end sensors (e.g., temperature, pressure) in portable diagnostic devices. IC Role / Device Role / Timing Role: Precision parameter store read once at startup, written only during manufacturing calibration or field service using authenticated I²C commands. Use Value: 1.7V operation enables direct interface with low-power MCU sleep modes, reducing standby current to <1 µA.	Use Scenario: Storing seat position presets, mirror adjustment profiles, and lighting configuration in automotive BCMs subjected to –40°C cold cranking and 85°C under-hood thermal stress. IC Role / Device Role / Timing Role: AEC-Q100 qualified nonvolatile memory retaining user preferences across ignition cycles and battery disconnect events. Use Value: Industrial temperature rating (–40°C to +85°C) and 400 kHz I²C speed ensure deterministic access timing within CAN-based vehicle networks.

Smart Energy Metering

Industrial PLC Configuration

Use Scenario: Storing tariff schedules, meter calibration constants, and tamper-event logs in utility-grade electricity meters operating unattended for 15+ years.

IC Role / Device Role / Timing Role: Nonvolatile configuration register holding time-critical calibration data accessed at power-on and updated infrequently via secure I²C commands.

Use Value: Eliminates need for battery-backed SRAM; leverages 200-year retention and 1M-cycle endurance to meet ANSI C12.20 and IEC 62056 compliance.

Use Scenario: Persisting I/O mapping, PID loop parameters, and safety interlock states in programmable logic controllers deployed in harsh factory environments.

IC Role / Device Role / Timing Role: Field-programmable memory storing user-defined control logic variables that survive power loss and firmware upgrades.

Use Value: Hardware write-protection (WP pin) prevents corruption during voltage transients common in 24V DC industrial buses.

Medical Sensor Calibration

Automotive Body Control Module

Use Scenario: Holding factory-trimmed offset/gain coefficients for analog front-end sensors (e.g., temperature, pressure) in portable diagnostic devices.

IC Role / Device Role / Timing Role: Precision parameter store read once at startup, written only during manufacturing calibration or field service using authenticated I²C commands.

Use Value: 1.7V operation enables direct interface with low-power MCU sleep modes, reducing standby current to <1 µA.

Use Scenario: Storing seat position presets, mirror adjustment profiles, and lighting configuration in automotive BCMs subjected to –40°C cold cranking and 85°C under-hood thermal stress.

IC Role / Device Role / Timing Role: AEC-Q100 qualified nonvolatile memory retaining user preferences across ignition cycles and battery disconnect events.

Use Value: Industrial temperature rating (–40°C to +85°C) and 400 kHz I²C speed ensure deterministic access timing within CAN-based vehicle networks.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
24LC256-I/SN	Requires minimum 2.5V VCC; identical pinout, timing, and memory architecture but higher voltage floor limits ultra-low-power use cases.	Not suitable for 1.8V systems; otherwise drop-in replacement in 3.3V/5V industrial controls where voltage margin exceeds 2.5V.	Select 24LC256-I/SN only if system VCC is guaranteed ≥2.5V and cost sensitivity outweighs low-voltage flexibility.
AT24C256-10PU-2.7	Same 256-Kbit capacity and SOIC-8 package; operates at 2.7–5.5V, lacks AEC-Q100 qualification, and has 400 kHz max clock (no 100 kHz fallback below 2.5V).	Valid for commercial-grade consumer electronics but not certified for automotive or extended-temperature industrial deployment.	Choose AT24C256-10PU-2.7 for cost-sensitive, non-automotive applications where AEC-Q100 and sub-2.5V operation are unnecessary.

Compared with 24AA256-E/SN, the 24LC256-I/SN sacrifices low-voltage capability for broader vendor availability, while the AT24C256-10PU-2.7 trades automotive qualification and flexible voltage range for lower unit cost in commercial designs.

Availability

24AA256-E/SN is available at Aetrix Electronics and suitable for smart energy metering, industrial PLC configuration, and medical sensor calibration requiring stable component supply across multi-year production cycles.

Supply support for 24AA256-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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with global manufacturing and quality certifications including ISO 9001 and IATF 16949.

The 24AA256 belongs to Microchip's 24XX256 family of I²C serial EEPROMs designed for robust, low-power nonvolatile data storage in industrial, automotive, and medical systems where reliability and long-term data integrity are critical.

FAQ

What is the minimum operating voltage for the 24AA256-E/SN?

The 24AA256-E/SN operates down to 1.7V, enabling direct integration into 1.8V systems without level-shifting circuitry. This specification is verified across the full industrial temperature range (–40°C to +85°C) and applies to all functions including read, write, and standby modes. Below 1.7V, the device may fail to initialize or retain data reliably.

Does the 24AA256-E/SN support standard I²C addressing and protocol?

Yes, the 24AA256-E/SN implements full I²C compliance with 7-bit addressing (base code 0x50), Start/Stop conditions, ACK/NACK handshaking, and clock stretching support. It accepts standard I²C write/read sequences and is interoperable with any I²C master - including ARM Cortex-M, PIC, and ESP32 microcontrollers - without custom drivers.

How does hardware write-protection work on the 24AA256-E/SN?

The 24AA256-E/SN uses a dedicated WP pin sampled only at the Stop condition of each write command. When WP = VCC, all write operations (byte and page) are inhibited - the device acknowledges the command but performs no memory update. Reads remain fully functional, and no firmware changes are needed to enforce this lock.

What is the maximum write speed for the 24AA256-E/SN?

The 24AA256-E/SN supports up to 400 kHz I²C clock frequency at VCC ≥ 2.5V, enabling theoretical peak write throughput of ~40 KB/s in page mode. Actual sustained speed depends on host controller timing margins and bus capacitance; worst-case page write cycle time remains ≤5 ms regardless of clock rate due to internal self-timed programming.

Is the 24AA256-E/SN qualified for automotive applications?

No - the 24AA256-E/SN carries the "E" suffix denoting Industrial temperature grade (–40°C to +85°C), not Automotive (AEC-Q100). While Microchip offers AEC-Q100-qualified variants like 24AA256T-I/SN, the -E/SN variant is intended for industrial, medical, and commercial applications where extended temperature or automotive qualification is not required.

24AA256-E/SN Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Active

Programmable:: Verified

Memory Type:: Non-Volatile

Memory Format:: EEPROM

Technology:: EEPROM

Memory Size:: 256Kbit

Memory Organization:: 32K x 8

Memory Interface:: I2C

Clock Frequency:: 400 kHz

Write Cycle Time - Word, Page:: 5ms

Access Time:: 900 ns

Voltage - Supply:: 1.7V ~ 5.5V

Operating Temperature:: -40°C ~ 125°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

24AA256-E/SN FAQ

1.How can I place an order for 24AA256-E/SN through Aetrix?

Please submit a Request for Quotation (RFQ) for 24AA256-E/SN on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 24AA256-E/SN reliable?

The price and inventory of 24AA256-E/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 24AA256-E/SN is usually 5 days.

3.What payment methods are accepted for 24AA256-E/SN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24AA256-E/SN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 24AA256-E/SN?

24AA256-E/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 24AA256-E/SN order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 24AA256-E/SN?

For technical support, including 24AA256-E/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24AA256-E/SN requirements.

6.How does Aetrix verify that 24AA256-E/SN is sourced from the original manufacturer or authorized distributors?

All 24AA256-E/SN products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 24AA256-E/SN meets industry standards.

7.What is the process for return or replacement of 24AA256-E/SN?

All 24AA256-E/SN units undergo pre-shipment inspection (PSI). If there is an issue with 24AA256-E/SN, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 24AA256-E/SN part is unused and in its original packaging.

Return procedure for 24AA256-E/SN:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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