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Microchip Technology AT24C256W-10SI
- Part No.:
- AT24C256W-10SI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
AT24C256W-10SI.pdf
- Description:
- IC EEPROM 256KBIT I2C 1MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,481
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Product details
Overview
AT24C256W-10SI from Microchip Technology (formerly Atmel) is a 256 Kbit (32,768 × 8) I²C-compatible serial EEPROM with low-voltage operation (2.7V to 5.5V), 400 kHz bus speed at 2.7V, and industrial temperature range (–40°C to +85°C). It features hardware write protection via WP pin, 64-byte page write capability, and 100,000 write cycles endurance - deployed in embedded control modules, sensor calibration storage, and power meter firmware retention.
For engineers reviewing the AT24C256W-10SI datasheet, AT24C256W-10SI pinout, AT24C256W-10SI application, or AT24C256W-10SI equivalent, key selection criteria include VCC operating range (2.7–5.5V), industrial-grade temperature rating, 8-pin SOIC package compatibility, and I²C timing compliance at 400 kHz under 2.7V supply.
Technical Context
The AT24C256W-10SI implements a standard two-wire I²C interface with open-drain SDA and Schmitt-triggered SCL inputs for noise immunity. Its memory array is organized as 32,768 words of 8 bits, internally segmented into 512 pages of 64 bytes each, supporting both byte and page write modes with automatic address incrementing within pages.
Write protection is enforced via the dedicated WP pin: tied high to VCC, it disables all write operations including page writes; left unconnected, it defaults to GND enabling full write access. The device enters low-power standby mode after STOP condition receipt and supports acknowledge polling to detect write cycle completion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8 bits), sufficient for storing configuration tables, calibration coefficients, or boot parameters in resource-constrained systems. |
| Supply Voltage Range | 2.7V to 5.5V - enables direct integration with 3.3V microcontrollers and legacy 5V logic without level-shifting. |
| I²C Clock Frequency | 400 kHz at 2.7V - ensures reliable communication in industrial environments while maintaining compatibility with standard I²C peripherals. |
| Page Write Capacity | 64-byte page writes - reduces firmware update time by up to 64× versus byte writes, critical for field-upgradable devices. |
| Endurance & Retention | 100,000 write cycles and 40-year data retention - meets long-life requirements for utility meters, medical diagnostics, and automotive subsystems. |
| Operating Temperature | –40°C to +85°C - qualified for industrial control cabinets, outdoor telemetry units, and factory automation nodes. |
| Write Protect Logic | Hardware-enabled via WP pin: logic-high inhibits all writes; floating defaults to enabled - simplifies secure firmware update workflows. |
Pinout & Package
AT24C256W-10SI is supplied in an 8-pin JEDEC SOIC (8S2) package, 0.200" wide, with gull-wing leads and standard 1.27 mm pitch. Pin 1 is marked with an index notch; package dimensions are 4.90 mm × 6.00 mm × 1.75 mm (L × W × H).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Device Address Input | Hardwired low/high to configure one of four possible I²C slave addresses (0x50–0x53); floating defaults to logic 0. |
| A1 | Device Address Input | Second address bit; used with A0 to support up to four AT24C256W-10SI devices on a shared I²C bus without address conflict. |
| NC | No Connect | Internally unconnected; must be left floating or tied to GND - no electrical function or signal routing required. |
| GND | Ground Reference | Primary return path for VCC and I/O signals; requires low-impedance connection to system ground plane for noise immunity. |
| VCC | Power Supply | Accepts 2.7–5.5V DC; decoupling capacitor (0.1 µF ceramic) recommended within 10 mm of pin for stable I²C timing. |
| WP | Write Protect Control | Active-high enable: logic high (≥0.7×VCC) locks entire memory array against accidental or malicious writes. |
| SCL | I²C Clock Input | Input-only clock line with Schmitt trigger and filtering - tolerates slow rise/fall times and EMI common in industrial wiring. |
| SDA | I²C Data I/O | Open-drain bidirectional line requiring external pull-up (typically 2.2–10 kΩ to VCC); supports multi-master arbitration. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Voltage Operation | Functional down to 2.7V - eliminates need for separate 5V rail in mixed-voltage systems using 3.3V MCUs. |
| Hardware Write Protection | WP pin provides tamper-resistant memory lockdown during firmware updates or field service - no software overhead required. |
| 64-Byte Page Writes | Reduces I²C transaction count per 64-byte block from 64 to 1, cutting bus occupancy and host CPU load in logging applications. |
| Industrial Temperature Rating | Validated operation from –40°C to +85°C - suitable for deployment in uncontrolled ambient environments like streetlight controllers or HVAC panels. |
| Noise-Immune Inputs | Schmitt-triggered SCL and filtered inputs suppress transients from relay switching or motor drives - improves reliability in electrically noisy plants. |
Applications
| Smart Energy Metering | Industrial PLC Configuration |
|---|---|
Use Scenario: Storing tariff schedules, pulse-count history, and cryptographic keys in DIN-rail mounted electricity meters exposed to wide ambient swings. IC Role / Device Role / Timing Role: Nonvolatile parameter store interfaced via I²C to an ARM Cortex-M3 MCU; retains data across mains outages and brownouts. Use Value: 40-year data retention and 100K write cycles ensure lifetime compliance with IEC 62056 standards without field replacement. | Use Scenario: Holding ladder logic configuration, I/O mapping, and calibration offsets in programmable logic controllers operating in factory-floor enclosures. IC Role / Device Role / Timing Role: Dedicated configuration EEPROM accessed during cold boot; isolated from main program flash to prevent corruption during firmware updates. Use Value: Hardware WP pin prevents runtime overwrites during ESD events or power glitches - critical for deterministic control loop behavior. |
| Medical Diagnostic Calibration | Automotive Body Control Module |
Use Scenario: Recording sensor gain/offset values and self-test results in portable ultrasound or blood glucose analyzers requiring traceable calibration logs. IC Role / Device Role / Timing Role: I²C-connected calibration vault; written once per manufacturing calibration, read at every power-on. Use Value: 2.7V minimum VCC allows direct use with single-cell Li-ion supplies (3.0–3.6V), eliminating voltage regulation overhead. | Use Scenario: Storing seat position presets, mirror angles, and lighting profiles in automotive body control units subject to automotive-grade thermal cycling. IC Role / Device Role / Timing Role: Persistent settings storage accessed by 8-bit or 32-bit MCU over I²C; survives battery disconnects and ignition cycles. Use Value: Industrial temperature grade (–40°C to +85°C) exceeds AEC-Q200 Grade 2 requirements, enabling cost-effective qualification without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STMicroelectronics M24256-BWMN6TP | Same 256 Kbit size, 2.5–5.5V supply, 400 kHz max I²C speed, but uses different device addressing (A0/A1 pins active only in 128K variant; 256K fixed address 0x50). | Requires PCB-level verification of I²C address collision if multiple devices present; lacks explicit 2.7V min spec in datasheet. | Select when sourcing ST-qualified supply chains or when leveraging existing M24xxx design libraries. |
| ON Semiconductor CAT24C256WI-GT3 | Identical 256 Kbit organization, 2.5–5.5V range, and 400 kHz speed, but rated only for commercial temperature (0°C to 70°C) and lacks industrial-grade qualification documentation. | Not suitable for deployments outside controlled indoor environments; may require thermal derating in enclosure designs. | Choose for cost-sensitive consumer electronics where extended temperature operation is not required. |
Compared with M24256-BWMN6TP and CAT24C256WI-GT3, AT24C256W-10SI uniquely combines guaranteed 2.7V operation, industrial temperature qualification, and explicit 400 kHz timing validation at that voltage - making it the preferred choice for ruggedized embedded systems demanding consistent performance across voltage and thermal margins.
Availability
AT24C256W-10SI is available at Aetrix Electronics and suitable for smart energy metering, industrial PLC configuration, and medical diagnostic calibration requiring stable component supply across extended product lifecycles.
Supply support for AT24C256W-10SI 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 is a global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions, with a focus on embedded control and connectivity.
The AT24C256W-10SI belongs to Microchip's legacy AT24C serial EEPROM family, designed specifically for robust, low-power, I²C-based parameter and configuration storage in industrial, automotive, and medical equipment.
FAQ
What is the maximum I²C clock frequency supported by AT24C256W-10SI at 2.7V?
The AT24C256W-10SI supports up to 400 kHz I²C clock frequency when operated at 2.7V, as validated in the official Microchip datasheet (Rev. 0670E). This is lower than its 1 MHz capability at 5V but ensures timing margin and noise resilience in low-voltage industrial systems where AT24C256W-10SI is commonly deployed.
Does AT24C256W-10SI support page write operations, and what is the page size?
Yes, AT24C256W-10SI supports 64-byte page write operations. Each page spans 64 consecutive bytes, and the internal address counter wraps within the page boundary - allowing efficient bulk writes without host-side address management. This feature is fully functional across the 2.7–5.5V supply range and is documented in the "Write Operations" section of the AT24C256W-10SI datasheet.
What is the function of the WP pin on AT24C256W-10SI, and how should it be connected?
The WP (Write Protect) pin on AT24C256W-10SI is an active-high input that disables all write operations when driven to VCC. When left unconnected, it is internally pulled down to GND, enabling normal writes. For secure operation, tie WP to VCC during critical firmware updates or leave it floating for default write-enable behavior - no external pull-down resistor is needed.
Is AT24C256W-10SI qualified for industrial temperature operation?
Yes, AT24C256W-10SI is explicitly rated for industrial temperature operation from –40°C to +85°C, as confirmed in the "Ordering Information" table (page 14) of the Microchip AT24C128/256 datasheet. The "-SI" suffix denotes the industrial-grade version, distinguishing it from commercial-grade variants like "-SC".
What package type is used for AT24C256W-10SI, and what are its key mechanical dimensions?
AT24C256W-10SI uses an 8-pin EIAJ SOIC package (designated 8S2), 0.200" wide, with 1.27 mm lead pitch. Its footprint measures 4.90 mm × 6.00 mm, height is 1.75 mm max, and it complies with JEDEC MS-012 standards - enabling drop-in compatibility with existing SOIC-8 layouts designed for similar serial EEPROMs.
AT24C256W-10SI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- I2C
- Clock Frequency:
- 1 MHz
- Write Cycle Time - Word, Page:
- 10ms
- Access Time:
- 550 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
AT24C256W-10SI FAQ
1.How can I place an order for AT24C256W-10SI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT24C256W-10SI 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 AT24C256W-10SI reliable?
The price and inventory of AT24C256W-10SI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT24C256W-10SI is usually 5 days.
3.What payment methods are accepted for AT24C256W-10SI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT24C256W-10SI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT24C256W-10SI?
AT24C256W-10SI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT24C256W-10SI 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 AT24C256W-10SI?
For technical support, including AT24C256W-10SI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT24C256W-10SI requirements.
6.How does Aetrix verify that AT24C256W-10SI is sourced from the original manufacturer or authorized distributors?
All AT24C256W-10SI 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 AT24C256W-10SI meets industry standards.
7.What is the process for return or replacement of AT24C256W-10SI?
All AT24C256W-10SI units undergo pre-shipment inspection (PSI). If there is an issue with AT24C256W-10SI, 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 AT24C256W-10SI part is unused and in its original packaging.
Return procedure for AT24C256W-10SI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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