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Microchip Technology AT25256-10PI
- Part No.:
- AT25256-10PI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
AT25256-10PI.pdf
- Description:
- IC EEPROM 256KBIT SPI 3MHZ 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,248
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Product details
Overview
AT25256-10PI from Atmel (now Microchip) is a 256 Kbit SPI serial EEPROM organized as 32,768 × 8-bit memory array, operating from 2.7V to 5.5V with 3 MHz max clock rate, 5 ms typical write cycle time, and industrial temperature range (–40°C to +85°C). It serves as nonvolatile configuration/data storage in microcontroller-based systems requiring low-power, byte- or page-level writes and hardware/software write protection.
For engineers reviewing the AT25256-10PI datasheet, AT25256-10PI pinout, AT25256-10PI application, or AT25256-10PI equivalent, key selection criteria include VCC voltage range compatibility (2.7–5.5 V), SPI Mode 0/3 support, block write protection granularity (1/4, 1/2, or full array), HOLD/CS timing behavior, and industrial-grade reliability metrics (100K write cycles, >200-year data retention).
Technical Context
The AT25256-10PI implements a synchronous slave SPI interface with separate SI (input) and SO (output) pins, supporting MSB-first transmission and op-code–driven command execution (e.g., WREN, WRITE, RDSR, WRSR). It uses an internal 8-bit instruction register and auto-incrementing address counter during sequential reads.
Write operations require explicit Write Enable (WREN) prior to WRITE or WRSR commands; the device remains in write-disable state at power-up. Block protection is controlled via nonvolatile BP0/BP1 bits in the status register, while WPEN enables or disables hardware write protection via the WP pin - both configurable only when write-enabled.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8-bit array) - supports firmware parameter storage, calibration data, and event logs without external memory controller. |
| Supply Voltage Range | 2.7 V to 5.5 V - interoperable with 3.3 V and 5 V logic domains, eliminating level-shifting in mixed-voltage designs. |
| Max Clock Frequency | 3 MHz - enables fast read/write throughput (up to 64-byte page writes) while maintaining timing margins across industrial temperature range. |
| Write Cycle Time | 5 ms typical - defines minimum interval between write commands; self-timed, no external erase cycle required. |
| Endurance & Retention | 100,000 write cycles / >200 years data retention - suitable for applications with frequent field updates (e.g., metering, industrial logging). |
| Operating Temperature | –40°C to +85°C - qualified for industrial control, automotive body electronics, and outdoor embedded systems. |
| ESD Protection | >4000 V HBM - reduces need for external ESD protection on SPI lines in harsh environments. |
Pinout & Package
AT25256-10PI is housed in an 8-pin EIAJ SOIC (0.200" wide) package, pin-compatible with JEDEC SOIC-8 footprints but with distinct lead pitch and body dimensions per Atmel specification 8S2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 CS | Chip Select | Active-low enable; must be low for all SPI transactions; high-Z SO output when CS high. |
| 2 SCK | Serial Clock Input | Master-generated clock; timing-critical for setup/hold of SI/SO; supports up to 3 MHz. |
| 3 SI | Serial Data Input | Receives op-codes, addresses, and write data; MSB-first; ignored during HOLD or write cycle. |
| 4 SO | Serial Data Output | Drives read data and status bits; tri-stated when CS high or during HOLD assertion. |
| 5 GND | Ground Reference | Primary return path for VCC and I/O; requires low-impedance PCB connection to minimize noise coupling. |
| 6 VCC | Power Supply | 2.7–5.5 V supply; decoupling capacitor (0.1 µF) recommended within 10 mm of pin. |
| 7 WP | Write Protect | Hardware lock for status register and protected memory blocks when WPEN = 1 and WP = low. |
| 8 HOLD | Communication Suspend | Pauses ongoing SPI transfer without resetting sequence; requires SCK low before assertion. |
Key Features
| Feature | Design Value |
|---|---|
| SPI Mode 0 & 3 Support | Compatible with dominant microcontroller families (e.g., STM32, PIC, MSP430) without protocol translation logic. |
| 64-byte Page Write | Reduces write overhead vs. byte-write: 64× faster bulk programming; address auto-increments within page boundary. |
| Configurable Block Protection | BP0/BP1 bits allow selective locking of top 1/4, 1/2, or entire memory - preserves critical boot/config data during field updates. |
| HOLD Pin Functionality | Enables multi-master arbitration or CPU interrupt servicing without losing SPI context - no re-synchronization needed. |
| Nonvolatile Status Register | BP0, BP1, and WPEN retain settings across power cycles - eliminates boot-time configuration code in host firmware. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
|
Use Scenario: Storing I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed via SPI during boot and runtime; HOLD used during real-time task preemption. Use Value: Ensures deterministic startup after power loss; block protection prevents accidental overwrite of safety-critical settings during firmware updates. |
Use Scenario: Retaining sensor calibration coefficients, usage counters, and audit logs in portable diagnostic equipment (e.g., blood glucose meters, pulse oximeters). IC Role / Device Role / Timing Role: Low-power data logger interfaced to ARM Cortex-M0+ MCU; operates at 3.3 V with <2 µA standby current. Use Value: >200-year data retention guarantees calibration validity over product lifetime; 100K endurance supports daily recalibration cycles for 27 years. |
| Automotive Body Control Module | Smart Energy Meter Firmware Parameters |
|
Use Scenario: Saving seat/mirror position presets, lighting profiles, and error codes in 12 V automotive body control units with local 3.3 V regulation. IC Role / Device Role / Timing Role: SPI EEPROM co-located with CAN/LIN transceiver MCU; withstands –40°C to +85°C ambient and load-dump transients. Use Value: Industrial temp grade ensures reliability under hood conditions; WP pin hardwired to chassis ground provides fail-safe write lock during ECU reset. |
Use Scenario: Storing tariff schedules, demand-response flags, and tamper-event timestamps in ANSI C12.22-compliant smart electricity meters. IC Role / Device Role / Timing Role: Secure parameter store with software-controlled block protection; RDSR polling used to verify write completion before metering resume. Use Value: 5 ms write time enables fast parameter updates during communication windows; >4 kV HBM ESD rating survives utility-grade surge events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| M95256-DRMN6TP/K | STMicroelectronics 256 Kbit SPI EEPROM; identical 8-pin SOIC package, same 2.7–5.5 V range, but rated for 5 MHz clock and 4 ms write time. | Higher speed suits burst-read telemetry; lacks HOLD pin - requires software-managed transaction suspension. | Select when system demands faster throughput and can accommodate software-based hold emulation. |
| 25AA256-I/P | Microchip 256 Kbit SPI EEPROM; pin-compatible 8-pin PDIP package, same voltage range and 3 MHz clock, but only offers 1/4 or full-array protection (no 1/2 option). | PDIP variant eases prototyping; reduced protection granularity limits flexible partitioning of config vs. log regions. | Select for through-hole evaluation or legacy board reuse where 1/2-array protection is not required. |
Compared with M95256-DRMN6TP/K and 25AA256-I/P, AT25256-10PI uniquely combines HOLD functionality, three-tier block protection (1/4, 1/2, full), and industrial temperature qualification in a compact SOIC-8 footprint - making it optimal for space-constrained, real-time embedded systems requiring robust data integrity.
Availability
AT25256-10PI is available at Aetrix Electronics and suitable for industrial control systems, medical diagnostics equipment, automotive body electronics, and smart energy metering applications requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for AT25256-10PI 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
Atmel Corporation, now part of Microchip Technology, is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and secure authentication ICs for industrial, automotive, and consumer markets.
The AT25xxx family was designed specifically for reliable, low-power serial data storage in resource-constrained embedded systems - emphasizing SPI simplicity, robust write protection, and extended temperature operation without external support circuitry.
FAQ
What voltage range does the AT25256-10PI support, and how does it affect system design?
The AT25256-10PI supports 2.7 V to 5.5 V, enabling direct interface with both 3.3 V and 5 V microcontrollers without level shifters. This simplifies power domain partitioning and reduces BOM count. Its guaranteed operation down to 2.7 V also supports brown-out resilience in battery-powered applications - critical for maintaining data integrity during voltage sag events in the AT25256-10PI.
Does the AT25256-10PI require an external erase cycle before writing?
No. The AT25256-10PI performs fully self-timed write cycles: once CS goes high after transmitting address and data, the internal write begins automatically and completes in ≤10 ms. No separate erase command or delay is needed - unlike flash memory, each byte or page is written directly, which streamlines firmware development for the AT25256-10PI.
How does the HOLD pin function differ from simply deasserting CS on the AT25256-10PI?
HOLD suspends SPI communication mid-sequence without resetting the internal state machine - allowing the master to service interrupts or switch tasks and resume exactly where it left off. In contrast, deasserting CS terminates the transaction, requiring full reinitialization (op-code + address) upon next access. This deterministic resumption is essential for real-time systems using the AT25256-10PI.
Can the AT25256-10PI's block protection be configured to protect only the last 1 KB of memory?
No. Block protection is fixed to top 1/4 (8 KB), top 1/2 (16 KB), or full (32 KB) of the 32 KB array - defined by BP0/BP1 bits. There is no granularity below 8 KB. To safeguard smaller regions like a 1 KB parameter sector, users must allocate it within a protected block and manage unprotected areas separately - a constraint inherent to the AT25256-10PI architecture.
Is the AT25256-10PI compatible with SPI Mode 1 or Mode 2 interfaces?
No. The AT25256-10PI explicitly supports only SPI Modes 0 (CPOL = 0, CPHA = 0) and 3 (CPOL = 1, CPHA = 1), as confirmed in its functional description and timing diagrams. Attempting Mode 1 or 2 will result in misaligned sampling and corrupted data transfers - firmware must configure the host SPI peripheral accordingly for reliable AT25256-10PI operation.
AT25256-10PI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- 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:
- 3 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
AT25256-10PI FAQ
1.How can I place an order for AT25256-10PI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT25256-10PI 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 AT25256-10PI reliable?
The price and inventory of AT25256-10PI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT25256-10PI is usually 5 days.
3.What payment methods are accepted for AT25256-10PI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT25256-10PI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT25256-10PI?
AT25256-10PI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT25256-10PI 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 AT25256-10PI?
For technical support, including AT25256-10PI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT25256-10PI requirements.
6.How does Aetrix verify that AT25256-10PI is sourced from the original manufacturer or authorized distributors?
All AT25256-10PI 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 AT25256-10PI meets industry standards.
7.What is the process for return or replacement of AT25256-10PI?
All AT25256-10PI units undergo pre-shipment inspection (PSI). If there is an issue with AT25256-10PI, 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 AT25256-10PI part is unused and in its original packaging.
Return procedure for AT25256-10PI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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