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Microchip Technology 25AA256T-E/MF
- Part No.:
- 25AA256T-E/MF
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-VDFN Exposed Pad
- Datasheet:
-
25AA256T-E/MF.pdf
- Description:
- IC EEPROM 256KBIT SPI 10MHZ 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,934
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Product details
Overview
25AA256T-E/MF from Microchip Technology Inc. is a 256 Kbit (32,768 × 8) SPI Serial EEPROM with 1.8–5.5 V supply range, 64-byte page write capability, and automotive-grade AEC-Q100 qualification for extended temperature operation (−40°C to +125°C). It features hardware write protection via WP pin and STATUS register, HOLD functionality for interrupt-safe bus suspension, and operates up to 10 MHz at 4.5–5.5 V.
For engineers reviewing the 25AA256T-E/MF datasheet, 25AA256T-E/MF pinout, 25AA256T-E/MF application, or 25AA256T-E/MF equivalent, this device serves as a drop-in replacement for legacy 25XX256-family EEPROMs in automotive control modules, industrial sensor nodes, and medical data loggers requiring high-reliability nonvolatile storage with low standby current (≤1 µA) and 1M endurance cycles.
Technical Context
The 25AA256T-E/MF implements a standard SPI Mode 0,0 or Mode 1,1 interface with separate SI/SO lines and CS-controlled selection. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and status register with WIP/WEL/BP0/BP1 bits enabling configurable block protection (none, 1/4, 1/2, or full array).
It supports sequential read with automatic address rollover, byte/page write with CS-driven internal write cycle initiation (TWC ≤ 5 ms), and HOLD pin assertion during active transfers to pause communication without sequence loss - all while maintaining SO tri-state integrity and input sampling on SCK rising edge.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8) organized as contiguous address space 0000h–7FFFh |
| Interface | SPI-compatible serial bus (Mode 0,0 / Mode 1,1); no I²C or UNI/O support |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5 V; de-rates to 5 MHz (2.5–4.5 V) and 3 MHz (1.8–2.5 V) |
| Write Cycle Time | ≤5 ms internal self-timed erase/write; no external timing control required |
| Endurance & Retention | 1,000,000 write/erase cycles; >200 years data retention at 25°C |
| Supply Voltage Range | 1.8 V to 5.5 V - enables direct interfacing with 1.8 V logic and mixed-voltage systems |
| Standby Current | ≤1 µA at VCC = 5.5 V and TA = 125°C - critical for battery-backed applications |
Pinout & Package
25AA256T-E/MF is packaged in an 8-lead DFN (Dual Flat No-lead) with wettable flank leads, measuring 2.0 mm × 3.0 mm × 0.55 mm (height), RoHS-compliant matte tin finish, and thermal pad exposed on underside for enhanced heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable; must be low for instruction/address/data transfer; rising edge initiates internal write cycle |
| SO | Serial Data Output | Tri-state output; data shifted out MSB-first on SCK falling edge; high-impedance when CS high or HOLD asserted |
| WP | Write-Protect Pin | Hardware lock for STATUS register writes when WPEN bit = 1; no effect on memory writes unless BP bits configured |
| VSS | Ground Reference | Primary return path for all internal circuitry and I/O; must be connected before VCC during power-up |
| SI | Serial Data Input | Instruction/address/data input; latched on SCK rising edge; requires setup/hold timing per AC specs |
| SCK | Serial Clock Input | Master-generated clock; defines timing for SI sampling and SO updates; max frequency depends on VCC |
| HOLD | Hold Input | Pauses ongoing SPI transaction when pulled low (SCK must be low); resumes on rising edge with SCK low |
| VCC | Supply Voltage | 1.8–5.5 V operating range; powers internal charge pump for EEPROM programming |
Key Features
| Feature | Design Value |
|---|---|
| Automotive Qualification | AEC-Q100 Grade 1 (−40°C to +125°C) - validated for engine control units and ADAS subsystems |
| Configurable Block Protection | BP0/BP1 bits allow selective write-protection of none, upper 1/4 (6000h–7FFFh), upper 1/2 (4000h–7FFFh), or full array |
| HOLD Functionality | Enables host MCU to service higher-priority interrupts mid-transfer without reinitializing SPI sequence |
| Low-Voltage Operation | Full functionality down to 1.8 V - supports integration with ultra-low-power microcontrollers and energy-harvesting systems |
| Power-On Write Protection | Write enable latch resets at power-up; prevents accidental writes during brown-out or reset conditions |
Applications
| Automotive Engine Control Unit | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing calibration tables, fault logs, and adaptive learning parameters in ECU firmware that survive ignition cycles and thermal stress. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed via SPI during boot and runtime; retains data across 15-year vehicle lifetime. Use Value: AEC-Q100 qualification ensures reliability under −40°C cold cranking and +125°C under-hood operation; 1M endurance supports frequent recalibration. |
Use Scenario: Holding user-defined I/O mapping, PID tuning constants, and firmware update metadata in modular programmable logic controllers. IC Role / Device Role / Timing Role: SPI-configurable parameter store updated infrequently but requiring guaranteed retention during factory power loss events. Use Value: Hardware WP pin + BP bits prevent corruption during firmware upload; ≤1 µA standby current extends backup battery life in mains-fail scenarios. |
| Medical Infusion Pump Data Logger | Smart Meter Firmware Patch Storage |
Use Scenario: Recording dose history, error timestamps, and maintenance alerts in Class II medical devices with strict data integrity requirements. IC Role / Device Role / Timing Role: Secure, tamper-resistant event log memory with verified write completion via RDSR polling of WIP bit. Use Value: >200-year data retention meets FDA long-term archival mandates; ESD >4 kV protects against handling damage during field servicing. |
Use Scenario: Storing encrypted firmware patches and cryptographic keys in utility meters deployed in remote, unattended locations. IC Role / Device Role / Timing Role: Trusted nonvolatile storage for secure OTA updates; accessed only during authenticated bootloader execution. Use Value: Page-write efficiency (64 bytes/burst) reduces update time over legacy 1-byte writes; HOLD support maintains bus integrity during RF interference bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25LC256T-E/MF | Same 256 Kbit SPI EEPROM, but 2.5–5.5 V VCC range; lacks 1.8 V compatibility | Not suitable for 1.8 V logic systems; otherwise identical pinout, timing, and feature set | Select when system VCC ≥ 2.5 V and AEC-Q100 compliance is required |
| AT25DF256A-MHN-T | 256 Mbit (not Kbit) SPI DataFlash with sector erase; different command set and no HOLD pin | Designed for firmware code storage, not parameter logging; incompatible page structure and protection model | Choose only for high-density code shadowing; not a functional substitute for 25AA256T-E/MF's EEPROM behavior |
Compared with 25LC256T-E/MF and AT25DF256A-MHN-T, the 25AA256T-E/MF uniquely supports 1.8 V operation and delivers deterministic 5 ms write cycles ideal for real-time parameter logging - whereas the former excludes low-voltage systems and the latter introduces erase latency and command incompatibility.
Availability
25AA256T-E/MF is available at Aetrix Electronics and suitable for automotive control units, industrial PLCs, and medical data loggers requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for 25AA256T-E/MF 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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25AA256T-E/MF belongs to Microchip's serial EEPROM product line, engineered specifically for automotive and industrial applications demanding extended temperature operation, high endurance, and robust data integrity under electrical stress.
FAQ
What is the minimum supply voltage for reliable operation of the 25AA256T-E/MF?
The 25AA256T-E/MF operates reliably from 1.8 V to 5.5 V. At 1.8 V, maximum clock frequency is 3 MHz, and DC characteristics including VOL/VOL remain within spec. Below 1.8 V, functionality is not guaranteed - the device will not power up or respond to commands. This 1.8 V threshold enables direct interfacing with modern ultra-low-power MCUs without level-shifting.
Does the 25AA256T-E/MF support SPI Mode 3,3 (CPOL=1, CPHA=1)?
No, the 25AA256T-E/MF supports only SPI Mode 0,0 (CPOL=0, CPHA=0) and Mode 1,1 (CPOL=1, CPHA=1) as defined in the datasheet. It does not support Mode 2,2 or Mode 3,3. The SO output updates after the falling edge of SCK, and SI is sampled on the rising edge - confirming strict adherence to Mode 0,0/1,1 timing. Attempting Mode 3,3 will result in corrupted reads/writes.
How does the HOLD pin function during an active write cycle in the 25AA256T-E/MF?
The HOLD pin has no effect once an internal write cycle (TWC) has begun - it cannot pause or abort an ongoing 5 ms EEPROM programming operation. HOLD is only effective during active SPI communication (instruction/address/data transfer) prior to CS rising edge initiation of TWC. During TWC, the device ignores all inputs except CS, and SO remains high-impedance until completion.
Can the 25AA256T-E/MF be used as a direct replacement for the 25AA256-I/MF in automotive designs?
Yes - the 25AA256T-E/MF is a temperature-extended (−40°C to +125°C) and automotive-qualified (AEC-Q100) variant of the industrial-grade 25AA256-I/MF. It shares identical pinout, timing, command set, and package (MF = 8-lead DFN). The "T-E" suffix denotes tape-and-reel packaging and extended temp grade, making it fully compatible in form, fit, and function for automotive deployments where wider thermal margin is required.
What happens if a page write crosses a 64-byte boundary in the 25AA256T-E/MF?
If a page write command attempts to cross a 64-byte physical page boundary (e.g., writing bytes starting at address 0x003F), data wraps around to the start of the same page (0x0000) instead of advancing to the next page. This overwrites previously written data within that page. The datasheet explicitly warns against crossing boundaries; software must enforce alignment checks or split writes across page boundaries to prevent unintended corruption.
25AA256T-E/MF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-VDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- 10 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN-S (6x5)
25AA256T-E/MF FAQ
1.How can I place an order for 25AA256T-E/MF through Aetrix?
Please submit a Request for Quotation (RFQ) for 25AA256T-E/MF 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 25AA256T-E/MF reliable?
The price and inventory of 25AA256T-E/MF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25AA256T-E/MF is usually 5 days.
3.What payment methods are accepted for 25AA256T-E/MF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25AA256T-E/MF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25AA256T-E/MF?
25AA256T-E/MF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25AA256T-E/MF 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 25AA256T-E/MF?
For technical support, including 25AA256T-E/MF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25AA256T-E/MF requirements.
6.How does Aetrix verify that 25AA256T-E/MF is sourced from the original manufacturer or authorized distributors?
All 25AA256T-E/MF 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 25AA256T-E/MF meets industry standards.
7.What is the process for return or replacement of 25AA256T-E/MF?
All 25AA256T-E/MF units undergo pre-shipment inspection (PSI). If there is an issue with 25AA256T-E/MF, 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 25AA256T-E/MF part is unused and in its original packaging.
Return procedure for 25AA256T-E/MF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25AA256T-E/MF Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
Microchip Technology
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AT24C02C-SSHM-T
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24LC01BT-I/OT
Microchip Technology
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M24C02-FMC6TG
STMicroelectronics
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AT24CS02-SSHM-T
Microchip Technology
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93LC46BT-I/OT
Microchip Technology
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AT24C04C-SSHM-T
Microchip Technology
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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AT24C08C-STUM-T
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