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Microchip Technology 25AA640A-E/MS
- Part No.:
- 25AA640A-E/MS
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
25AA640A-E/MS.pdf
- Description:
- IC EEPROM 64KBIT SPI 10MHZ 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,964
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Product details
Overview
25AA640A-E/MS from Microchip Technology Inc. is a 64-Kbit SPI Serial EEPROM with 8192 × 8-bit organization, 32-byte page size, and 1.8V–5.5V supply range. It supports up to 10 MHz clock frequency at 4.5–5.5V, offers 1 million erase/write cycles, and features hardware write protection via WP pin and STATUS register control. It is used in embedded systems for nonvolatile parameter storage in industrial controllers and sensor nodes.
For engineers reviewing the 25AA640A-E/MS datasheet, 25AA640A-E/MS pinout, 25AA640A-E/MS application, or 25AA640A-E/MS equivalent, key selection criteria include voltage compatibility (1.8V min), page-write boundary handling, HOLD functionality for interrupt-safe SPI transactions, and AEC-Q100-qualified extended temperature operation.
Technical Context
The 25AA640A-E/MS implements a standard SPI Mode 0,0/Motorola-compatible interface with separate SI (data in) and SO (data out) lines, requiring CS, SCK, SI, SO, WP, HOLD, and VCC/VSS. Its internal architecture includes a 32-byte page latch, status register with BP0/BP1 block protection bits, and hardware-controlled write-enable logic that resets on power-up or WRDI.
It supports sequential read with automatic address increment, byte/page write with self-timed 5 ms max internal write cycle, and HOLD pin suspension of ongoing SPI transfers without sequence restart. The device maintains high-impedance SO during CS high or HOLD low, enabling multi-device SPI bus sharing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8192 × 8-bit array), sufficient for firmware configuration tables or calibration data in resource-constrained microcontrollers. |
| Interface | SPI-compatible serial bus (Mode 0,0), requiring only four signal lines (CS, SCK, SI, SO) plus optional WP/HOLD - minimizes MCU GPIO usage. |
| Page Size | 32 bytes; write operations crossing physical page boundaries wrap within the same page - requires firmware alignment checks before page writes. |
| Write Endurance | 1,000,000 erase/write cycles per memory location, enabling reliable logging or counter applications over product lifetime. |
| Data Retention | Greater than 200 years at +25°C, ensuring long-term integrity of stored calibration or security keys without refresh. |
| Operating Voltage | 1.8V to 5.5V supply range - interoperable with both 3.3V and 5V systems, including battery-powered IoT edge nodes. |
| Temperature Range | −40°C to +125°C (Extended grade), qualified per AEC-Q100 - suitable for under-hood automotive modules and industrial motor drives. |
Pinout & Package
25AA640A-E/MS is packaged in an 8-lead MSOP (150 mil body), with exposed pad optionally connected to VSS. Pin functions are electrically identical across all 8-lead variants (SOIC, TSSOP, DFN, etc.) per Microchip's device selection table.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable; deselecting forces standby mode and tri-states SO - enables multi-device SPI bus sharing. |
| SO | Serial Data Output | CMOS output driven after falling SCK edge; high-impedance when CS high or HOLD low - prevents bus contention. |
| WP | Write-Protect Pin | Hardware lock for STATUS register nonvolatile bits when WPEN=1; grounded to disable writes - provides tamper-resistant configuration lockdown. |
| VSS | Ground Reference | Primary return path for all I/O and core logic; must be low-impedance to ensure noise immunity during fast SPI transfers. |
| SI | Serial Data Input | Latches instruction/address/data on rising SCK edge - timing-critical input requiring clean clock synchronization. |
| SCK | Serial Clock Input | Master-generated clock; rising edge clocks SI, falling edge updates SO - defines maximum 10 MHz interface speed at 5.5V. |
| HOLD | Serial Transfer Suspend | Pauses active SPI sequence when pulled low while SCK is low - allows host MCU to service higher-priority interrupts without retransmission. |
| VCC | Supply Voltage | 1.8V–5.5V core and I/O supply; powers internal HV generator for EEPROM programming - decoupling capacitor required near pin. |
Key Features
| Feature | Design Value |
|---|---|
| Block Write Protection | Configurable via BP0/BP1 bits to protect none, upper 1/4 (1800h–1FFFh), upper 1/2 (1000h–1FFFh), or entire array - enables secure partitioning of user vs. factory data. |
| Power-On Write Protection | Automatic reset of write enable latch at power-up, combined with WREN/WRDI commands - prevents accidental writes during brown-out or reset conditions. |
| Self-Timed Internal Write Cycle | Max 5 ms duration; no external timing control needed - simplifies firmware by eliminating busy-wait loops for write completion. |
| HOLD Functionality | Tri-states SI/SO/SCK during pause and resumes from exact point - eliminates need for transaction buffering or state reconstruction in interrupt-driven hosts. |
| Low Standby Current | 1 µA at 5.5V and +85°C - extends battery life in always-on sensor nodes or energy-harvesting applications. |
Applications
| Industrial PLC Configuration Storage | Automotive ECU Calibration Data |
|---|---|
Use Scenario: Storing I/O mapping, PID tuning parameters, and alarm thresholds in programmable logic controllers operating in harsh factory environments. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed via SPI during boot and runtime updates; HOLD pin enables safe parameter reload during motion-control interrupts. Use Value: AEC-Q100 qualification and −40°C to +125°C operation ensure reliability in uncontrolled cabinet temperatures; 1M endurance supports decades of field recalibration. |
Use Scenario: Holding engine trim values, sensor offset corrections, and diagnostic fault logs in powertrain control units subject to thermal cycling and EMI. IC Role / Device Role / Timing Role: Secure, write-protected storage for safety-critical calibration data; WP pin + BP bits prevent unauthorized modification during dealership reprogramming. Use Value: Hardware write protection and >200-year data retention guarantee integrity of emission-critical parameters across vehicle lifetime without backup power. |
| Medical Device Setup Profiles | Smart Meter Firmware Parameters |
Use Scenario: Saving user-defined therapy settings, alarm limits, and device ID in portable infusion pumps and patient monitors requiring regulatory traceability. IC Role / Device Role / Timing Role: Tamper-evident configuration store with STATUS register locking; RDSR polling confirms write readiness before critical updates. Use Value: 1.8V minimum VCC enables direct connection to low-power MCU rails; RoHS compliance and ESD >4 kV support cleanroom assembly and field robustness. |
Use Scenario: Storing tariff schedules, metering constants, and communication credentials in utility smart meters deployed in outdoor enclosures. IC Role / Device Role / Timing Role: Long-life parameter memory interfaced to metrology SoC via SPI; sequential read supports rapid credential verification during AMI network handshakes. Use Value: 5 mA max read current at 10 MHz enables fast credential loading without compromising battery backup runtime during mains failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25LC640A-E/MS | Requires minimum 2.5V VCC; otherwise identical pinout, timing, and feature set. | Not suitable for 1.8V–2.4V systems; otherwise drop-in replacement in 3.3V/5V designs with same temperature grade. | Select 25LC640A-E/MS only if system VCC never falls below 2.5V; verify compatibility with existing 25AA640A-E/MS firmware. |
| AT25DF641A-MAU-T | 8-pin SOIC package only; supports dual/quad SPI modes and faster 80 MHz read; lacks HOLD pin and hardware WP. | Better throughput for firmware read access but no interrupt-safe suspend; requires different driver stack due to command set divergence. | Choose AT25DF641A-MAU-T only when high-speed read performance outweighs need for HOLD/WP; not recommended for legacy 25AA640A-E/MS drop-in use. |
Compared with 25LC640A-E/MS, the 25AA640A-E/MS enables lower-voltage operation down to 1.8V, while the AT25DF641A-MAU-T trades HOLD/WP functionality for higher read bandwidth and quad-SPI capability - making it unsuitable as a functional substitute without firmware redesign.
Availability
25AA640A-E/MS is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical device manufacturing requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 25AA640A-E/MS 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, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25AA640A belongs to Microchip's serial EEPROM product line, designed specifically for robust, low-power nonvolatile data storage in automotive, industrial, and consumer applications demanding high endurance and extended temperature reliability.
FAQ
What is the minimum operating voltage for the 25AA640A-E/MS?
The 25AA640A-E/MS operates from 1.8V to 5.5V, enabling direct integration with 1.8V, 2.5V, 3.3V, and 5V microcontroller systems. This wide VCC range ensures compatibility with mixed-voltage designs and battery-powered applications where supply may dip below 2.5V.
Does the 25AA640A-E/MS support page write operations across address boundaries?
No, the 25AA640A-E/MS restricts page writes to within a single 32-byte physical page. Attempting to write across a page boundary causes data to wrap to the start of the same page, potentially overwriting prior data. Firmware must validate address alignment before initiating page writes.
How does the HOLD pin function during an active SPI transaction on the 25AA640A-E/MS?
When the HOLD pin is pulled low while SCK is low, the 25AA640A-E/MS suspends the ongoing SPI sequence, tri-states SI/SO/SCK, and ignores further input transitions. Resuming requires bringing HOLD high while SCK remains low - the device continues exactly where it left off without reinitialization.
What protection mechanisms prevent accidental writes to the 25AA640A-E/MS?
The 25AA640A-E/MS uses multiple safeguards: a write enable latch reset on power-up, mandatory WREN instruction before writes, automatic latch reset after each write, and hardware WP pin control enabled via the WPEN bit in the STATUS register - collectively preventing spurious writes during noise or reset events.
Is the 25AA640A-E/MS pin-compatible with other Microchip 64-Kbit SPI EEPROMs?
Yes, the 25AA640A-E/MS shares identical pinout, electrical characteristics, and instruction set with 25LC640A-E/MS and other members of the 25XX640A family across all 8-lead packages (MSOP, SOIC, TSSOP, etc.), enabling direct substitution where voltage and temperature requirements align.
25AA640A-E/MS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 64Kbit
- Memory Organization:
- 8K 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-MSOP
25AA640A-E/MS FAQ
1.How can I place an order for 25AA640A-E/MS through Aetrix?
Please submit a Request for Quotation (RFQ) for 25AA640A-E/MS 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 25AA640A-E/MS reliable?
The price and inventory of 25AA640A-E/MS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25AA640A-E/MS is usually 5 days.
3.What payment methods are accepted for 25AA640A-E/MS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25AA640A-E/MS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25AA640A-E/MS?
25AA640A-E/MS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25AA640A-E/MS 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 25AA640A-E/MS?
For technical support, including 25AA640A-E/MS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25AA640A-E/MS requirements.
6.How does Aetrix verify that 25AA640A-E/MS is sourced from the original manufacturer or authorized distributors?
All 25AA640A-E/MS 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 25AA640A-E/MS meets industry standards.
7.What is the process for return or replacement of 25AA640A-E/MS?
All 25AA640A-E/MS units undergo pre-shipment inspection (PSI). If there is an issue with 25AA640A-E/MS, 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 25AA640A-E/MS part is unused and in its original packaging.
Return procedure for 25AA640A-E/MS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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