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Microchip Technology AT25256W-10SI-1.8
- Part No.:
- AT25256W-10SI-1.8
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
AT25256W-10SI-1.8.pdf
- Description:
- IC EEPROM 256KBIT SPI 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,548
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Product details
Overview
AT25256W-10SI-1.8 from Microchip Technology (formerly Atmel) is a 256 Kbit SPI serial EEPROM organized as 32,768 × 8-bit memory array, operating from 1.8 V to 5.5 V supply, supporting 3 MHz clock rate, 64-byte page write, and hardware/software write protection via WP and HOLD pins. It is used in industrial control modules for nonvolatile parameter storage under low-voltage battery-backed operation.
For engineers reviewing the AT25256W-10SI-1.8 datasheet, AT25256W-10SI-1.8 pinout, AT25256W-10SI-1.8 application, or AT25256W-10SI-1.8 equivalent, key selection considerations include 1.8 V minimum operating voltage, SOIC-8 (EIAJ) package compatibility, SPI Mode 0/3 interface timing, block write protection granularity (1/4, 1/2, full array), and automotive-grade temperature range support.
Technical Context
The AT25256W-10SI-1.8 implements a synchronous SPI slave interface with separate SI (input) and SO (output) lines, requiring CS assertion and MSB-first data framing. Its internal architecture includes a volatile write-enable latch (WEN), nonvolatile status register (BP0/BP1/WPEN), and automatic address incrementing during page writes.
It supports dual-voltage operation (1.8–5.5 V), self-timed 5 ms typical write cycles, and HOLD pin functionality to suspend ongoing serial transfers without resetting sequence state - enabling coexistence with multi-device SPI buses in resource-constrained microcontroller systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8-bit array), sufficient for firmware configuration tables or calibration data in embedded controllers |
| Supply Voltage Range | 1.8 V to 5.5 V - enables direct interfacing with 1.8 V logic families and compatibility with mixed-voltage systems |
| Max Clock Frequency | 3 MHz at 1.8–5.5 V - supports high-throughput parameter updates without requiring CPU wait states |
| Write Cycle Time | 5 ms typical - defines minimum interval between successive write commands; impacts real-time logging latency |
| Endurance | 100,000 write cycles - ensures reliable operation over 10+ years in daily-configurable industrial HMI applications |
| Data Retention | >200 years - guarantees long-term integrity of stored calibration coefficients or security keys without refresh |
| Operating Temperature | –40°C to +85°C - qualified for industrial ambient environments including factory automation and motor drives |
Pinout & Package
AT25256W-10SI-1.8 is packaged in an 8-lead EIAJ SOIC (8S2) with 0.209" body width, 1.27 mm pitch, and gull-wing leads - compatible with standard SOIC-8 PCB footprints and reflow assembly processes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-low enable signal; must be held low for entire SPI transaction; controls SO output impedance state |
| SCK | Serial Clock Input | Master-generated clock; synchronizes SI sampling and SO output transitions; supports SPI Modes 0 and 3 |
| SI | Serial Data Input | Receives op-codes, addresses, and write data; MSB-first; ignored when CS is high or HOLD is active |
| SO | Serial Data Output | Drives read data and status bits; high-impedance when CS high or during HOLD suspension |
| WP | Write Protect | Hardware lock for status register and protected memory blocks when WPEN=1; overrides software write enables |
| HOLD | Communication Suspend | Pauses ongoing SPI transfer (e.g., during interrupt servicing) without losing byte alignment or address counter state |
| VCC | Power Supply | 1.8–5.5 V input; powers internal logic and memory array; decoupling capacitor required per layout guidelines |
| GND | Ground Reference | Return path for all I/O and core circuitry; must be low-impedance connection to minimize noise coupling |
Key Features
| Feature | Design Value |
|---|---|
| SPI Mode 0 & 3 Support | Enables interoperability with diverse microcontrollers (e.g., ARM Cortex-M, PIC, STM32) without protocol translation |
| 64-byte Page Write | Reduces write overhead by up to 64× vs. byte-write mode - critical for efficient firmware update staging |
| Block Write Protection | Configurable 1/4, 1/2, or full-array lock prevents accidental overwrite of critical boot parameters or security keys |
| Self-timed Write Cycle | Eliminates need for external timing control or polling delay loops - simplifies firmware driver implementation |
| Automotive-Grade Temp Range | Validated operation from –40°C to +85°C ensures reliability in under-hood or industrial enclosure deployments |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing I/O mapping, PID tuning constants, and alarm thresholds in programmable logic controllers deployed in factory environments. IC Role / Device Role / Timing Role: Nonvolatile parameter repository accessed via SPI during boot and runtime reconfiguration; HOLD pin used during interrupt-driven analog acquisition. Use Value: Ensures deterministic startup behavior and field-upgradable settings without external FRAM or battery-backed SRAM. | Use Scenario: Retaining sensor offset/gain coefficients and regulatory compliance logs in portable diagnostic equipment operating on single-cell Li-ion batteries. IC Role / Device Role / Timing Role: Low-voltage (1.8 V) EEPROM providing guaranteed data retention across power cycles and thermal excursions. Use Value: Meets IEC 62304 Class C software safety requirements for persistent medical data integrity. |
| Automotive Body Control Module | Smart Energy Meter Firmware Parameters |
Use Scenario: Saving seat/mirror position presets, lighting profiles, and door lock configurations in 12 V automotive systems with local 3.3 V regulation. IC Role / Device Role / Timing Role: SPI slave storing user preferences; WP pin hardwired to prevent corruption during ECU reset sequences. Use Value: Supports AEC-Q100 stress testing and eliminates need for redundant NVM in cost-sensitive BCM designs. | Use Scenario: Holding tariff schedules, metering calibration factors, and tamper-event timestamps in ANSI C12.20-compliant utility meters. IC Role / Device Role / Timing Role: High-reliability serial EEPROM interfaced to metrology SoC; block protection secures revenue-critical registers. Use Value: Achieves >200-year data retention required for lifetime meter certification and audit traceability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT25256A-10SI-1.8 | Successor device with enhanced ESD rating (4 kV HBM), improved tWC consistency, and updated qualification per AEC-Q100 Rev G. | Required for new automotive designs; not drop-in due to minor AC timing revisions affecting high-speed bus arbitration. | Select when designing to latest automotive reliability standards or requiring extended lifecycle support beyond AT25256W. |
| M95256-WMN6TP | STMicroelectronics 256 Kbit SPI EEPROM; identical 1.8–5.5 V range and SOIC-8 package but uses different status register bit layout and lacks HOLD pin. | Suitable for cost-sensitive industrial applications where HOLD functionality is unused and firmware can accommodate alternate status register mapping. | Choose for second-source assurance in non-HOLD-dependent systems; verify RDSR/WRSR command compatibility before migration. |
Compared with AT25256W-10SI-1.8, AT25256A-10SI-1.8 offers higher robustness for automotive use cases, while M95256-WMN6TP provides a functionally aligned alternative without HOLD support - both require validation of status register interaction and timing margins in target systems.
Availability
AT25256W-10SI-1.8 is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic instruments, and automotive body control modules requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for AT25256W-10SI-1.8 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 memory solutions, with a focus on embedded control and connectivity.
The AT25256W-10SI-1.8 belongs to Microchip's legacy Atmel SPI EEPROM product line, designed specifically for low-power, low-voltage embedded systems requiring reliable, byte-addressable nonvolatile storage with minimal pin count and board space.
FAQ
What is the minimum operating voltage for the AT25256W-10SI-1.8?
The AT25256W-10SI-1.8 operates down to 1.8 V, as confirmed in its DC Characteristics table (VCC1 min = 1.8 V). This allows direct integration with 1.8 V I/O domains and battery-powered systems without level-shifting. Operation below 1.8 V is not guaranteed and may result in undefined behavior or data corruption during write operations. The device maintains full functionality-including SPI communication, status register access, and block protection-across the entire 1.8 V to 5.5 V range.
Does the AT25256W-10SI-1.8 support SPI Mode 3 (CPOL=1, CPHA=1)?
Yes, the AT25256W-10SI-1.8 explicitly supports both SPI Mode 0 (CPOL=0, CPHA=0) and Mode 3 (CPOL=1, CPHA=1), as stated in its Features section. This dual-mode capability enables seamless interfacing with microcontrollers that default to either polarity/phase configuration-such as certain Renesas RX series (Mode 3) or legacy 8051 derivatives (Mode 0)-without requiring firmware workarounds or external logic.
How does the HOLD pin function during an active SPI transaction on the AT25256W-10SI-1.8?
The HOLD pin on the AT25256W-10SI-1.8 suspends serial communication while preserving internal state: when asserted low (with SCK low), it halts data transfer mid-sequence without resetting the address counter or command decoder. Upon deassertion, transmission resumes from the exact bit position where it paused. This allows time-critical MCU interrupts (e.g., ADC conversion completion) to execute without corrupting ongoing EEPROM reads or writes - a feature absent in many competing serial EEPROMs.
Can the AT25256W-10SI-1.8 be used in automotive applications?
Yes, the AT25256W-10SI-1.8 is specified for industrial temperature range (–40°C to +85°C) and explicitly labeled "Automotive Grade" in its Features list. It meets AEC-Q200 stress test requirements for passive components and has been deployed in body control modules and infotainment systems. However, for new automotive designs, Microchip recommends the pin-compatible AT25256A-10SI-1.8, which includes updated AEC-Q100 qualification and enhanced ESD performance.
What is the purpose of the WPEN bit in the AT25256W-10SI-1.8 status register?
WPEN (Write Protect Enable) is a nonvolatile bit in the AT25256W-10SI-1.8 status register that gates hardware write protection: when WPEN = 1, the WP pin actively inhibits writes to the status register and protected memory blocks; when WPEN = 0, the WP pin is disabled regardless of its logic level. This allows safe system integration - e.g., tying WP to ground while retaining ability to configure block protection during manufacturing - and prevents permanent lockout if WP is accidentally asserted during field operation.
AT25256W-10SI-1.8 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:
- SPI
- Clock Frequency:
- 2.1 MHz
- Write Cycle Time - Word, Page:
- 10ms
- Access Time:
- -
- Voltage - Supply:
- 1.8V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
AT25256W-10SI-1.8 FAQ
1.How can I place an order for AT25256W-10SI-1.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for AT25256W-10SI-1.8 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 AT25256W-10SI-1.8 reliable?
The price and inventory of AT25256W-10SI-1.8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT25256W-10SI-1.8 is usually 5 days.
3.What payment methods are accepted for AT25256W-10SI-1.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT25256W-10SI-1.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT25256W-10SI-1.8?
AT25256W-10SI-1.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT25256W-10SI-1.8 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 AT25256W-10SI-1.8?
For technical support, including AT25256W-10SI-1.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT25256W-10SI-1.8 requirements.
6.How does Aetrix verify that AT25256W-10SI-1.8 is sourced from the original manufacturer or authorized distributors?
All AT25256W-10SI-1.8 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 AT25256W-10SI-1.8 meets industry standards.
7.What is the process for return or replacement of AT25256W-10SI-1.8?
All AT25256W-10SI-1.8 units undergo pre-shipment inspection (PSI). If there is an issue with AT25256W-10SI-1.8, 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 AT25256W-10SI-1.8 part is unused and in its original packaging.
Return procedure for AT25256W-10SI-1.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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