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Microchip Technology 25LC640A-H/SN
- Part No.:
- 25LC640A-H/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
25LC640A-H/SN.pdf
- Description:
- IC EEPROM 64KBIT SPI 5MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:741
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Product details
Overview
25LC640A-H/SN from Microchip Technology Inc. is a 64 Kbit (8,192 × 8) SPI serial EEPROM with extended temperature operation (–40°C to +150°C), 5 MHz max clock speed, 32-byte page size, and built-in hardware write protection via WP pin and STATUS register control. It supports byte- and page-write operations with self-timed 6 ms internal write cycles and is AEC-Q100 qualified for automotive under-hood applications.
For engineers reviewing the 25LC640A-H/SN datasheet, 25LC640A-H/SN pinout, 25LC640A-H/SN application, or 25LC640A-H/SN equivalent, key selection criteria include high-temp SPI EEPROM compatibility, block-level write protection granularity (none/¼/½/all), endurance (>1M cycles), data retention (>200 years), and SOIC-8 packaging with RoHS compliance.
Technical Context
The 25LC640A-H/SN implements a standard SPI Mode 0,0 interface with separate SI (data in) and SO (data out) lines, requiring CS, SCK, and HOLD for full protocol support. Its internal architecture includes an 8-bit instruction register, page latches, HV generator, and EEPROM array with X/Y decoding and sense amplifiers.
It features dual-layer write protection: volatile WEL latch (set/reset via WREN/WRDI) and nonvolatile BP0/BP1 bits controlling 0%, 25%, 50%, or 100% array protection; WPEN bit enables/disables hardware write-protection via the WP pin. HOLD pin suspends ongoing SPI transfers without resetting the sequence.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Density | 64 Kbit (8,192 × 8 organization) - supports firmware parameter storage or calibration data logging in space-constrained systems |
| Max Clock Speed | 5 MHz at VCC ≥ 4.5V - enables fast read/write in high-throughput microcontroller interfaces |
| Page Size | 32 bytes - defines maximum contiguous write length before internal write cycle initiation |
| Write Cycle Time | 6 ms max - determines minimum time between write commands; impacts real-time logging latency |
| Endurance | >1,000,000 erase/write cycles - ensures long-term reliability in frequently updated configuration storage |
| Data Retention | >200 years at +150°C - guarantees data integrity over full automotive lifetime under extreme thermal stress |
| Temp Range | –40°C to +150°C (H grade) - validated for engine control units, transmission modules, and powertrain sensors |
Pinout & Package
8-Lead SOIC (SN) package, 3.90 mm body width, RoHS-compliant matte tin finish, JEDEC MS-012AC standard footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select Input | Active-low enable; must go high after final data bit to trigger internal write cycle; deselects device and tri-states SO |
| SO (Pin 2) | Serial Data Output | Tri-state open-drain output; data shifted out on SCK falling edge; high-impedance when CS high or HOLD low |
| WP (Pin 3) | Write-Protect Input | Hardware lock for STATUS register nonvolatile bits when WPEN=1; no effect if WPEN=0 |
| VSS (Pin 4) | Ground Reference | Primary return path for all I/O and core logic; requires low-impedance PCB connection to minimize noise coupling |
| SI (Pin 5) | Serial Data Input | CMOS input; latches instruction/address/data on SCK rising edge; accepts SPI Mode 0,0 protocol only |
| SCK (Pin 6) | Serial Clock Input | Master-generated clock; timing-critical for setup/hold compliance; rise/fall times ≤2 μs required |
| HOLD (Pin 7) | Hold Input | Pauses active SPI transfer when pulled low during SCK low phase; resumes on rising edge of HOLD while SCK low |
| VCC (Pin 8) | Supply Voltage | 2.5V–5.5V operation; decoupling capacitor (0.1 μF ceramic) required within 5 mm of pin for stable read/write margins |
Key Features
| Feature | Design Value |
|---|---|
| Block Write Protection | Selectable 0%, 25%, 50%, or 100% array protection via BP0/BP1 bits - prevents accidental overwrite of critical calibration or safety parameters |
| Power-On Write Protection | WEL latch resets at power-up and after every write - eliminates spurious writes during brown-out or reset conditions |
| HOLD Functionality | Non-disruptive SPI pause/resume without retransmission - enables host MCU to service higher-priority interrupts mid-sequence |
| AEC-Q100 Qualification | Qualified for automotive Grade 0 (–40°C to +150°C) - meets reliability requirements for engine control, braking, and ADAS subsystems |
| ESD Robustness | 4 kV HBM ESD rating on all pins - reduces risk of field failure in handling-sensitive manufacturing or service environments |
Applications
| Engine Control Unit (ECU) | Advanced Driver Assistance Systems (ADAS) |
|---|---|
Use Scenario: Storing adaptive fuel trim tables, knock sensor learning values, and emission calibration constants subject to frequent updates during vehicle operation. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced directly to PIC® MCU SPI port; retains data across ignition cycles and thermal cycling. Use Value: >200-year data retention at +150°C ensures calibration persistence over full vehicle lifetime without refresh; 64 Kbit capacity accommodates multi-map tuning tables. | Use Scenario: Logging radar sensor calibration offsets and camera alignment parameters updated during factory calibration and periodic field recalibration. IC Role / Device Role / Timing Role: SPI EEPROM used for secure, tamper-resistant storage of sensor-specific coefficients; accessed during boot and maintenance mode. Use Value: Hardware write protection (WP + WPEN) prevents unauthorized modification of safety-critical calibration data; AEC-Q100 qualification validates operation in vibration-prone mounting locations. |
| Industrial Motor Drives | Commercial HVAC Controllers |
Use Scenario: Holding motor thermal model coefficients, current limit thresholds, and fault history logs updated during runtime diagnostics. IC Role / Device Role / Timing Role: High-reliability nonvolatile memory co-located with motor control ASIC; withstands repeated thermal cycling in enclosed drive enclosures. Use Value: >1M endurance cycles support daily firmware updates and parameter tuning over 10+ years; 32-byte page writes optimize update efficiency for multi-parameter sets. | Use Scenario: Storing seasonal setpoint schedules, occupancy profiles, and compressor wear metrics updated weekly via BMS network. IC Role / Device Role / Timing Role: Low-power SPI EEPROM interfaced to HVAC controller MCU; operates continuously in ambient temperatures up to +85°C with margin. Use Value: 10 μA standby current minimizes battery drain in backup-powered controllers; RoHS compliance meets global building equipment regulations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SPI serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT25DF641A-SHN-T | 64 Mbit density, quad SPI interface, 85 MHz max clock, 4-KB sector erase - not pin-compatible; requires firmware rewrite for QSPI support | Targeted at high-speed code shadowing or firmware storage, not parameter/configuration EEPROM use | Choose only if migrating to flash-based storage with faster throughput and larger capacity; not a drop-in replacement |
| 25AA640A-I/SN | Same 64 Kbit density, SOIC-8 package, and SPI interface but rated for –40°C to +85°C (I grade); lacks AEC-Q100 qualification and 150°C operation | Valid for commercial/industrial control panels but unsuitable for under-hood automotive deployment | Select when cost sensitivity outweighs extended temperature requirement and automotive qualification is unnecessary |
Compared with AT25DF641A-SHN-T and 25AA640A-I/SN, the 25LC640A-H/SN uniquely delivers automotive-grade reliability at +150°C with proven EEPROM endurance and deterministic 6 ms write timing-critical for safety-critical parameter storage where predictability trumps raw speed or density.
Availability
25LC640A-H/SN is available at Aetrix Electronics and suitable for automotive powertrain control, ADAS sensor calibration, industrial motor drives, and commercial HVAC systems requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for 25LC640A-H/SN 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 microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25LCxxx family was designed specifically for robust, high-temperature SPI EEPROM applications in automotive, industrial, and aerospace systems where data integrity, endurance, and qualification rigor are mandatory.
FAQ
What is the maximum operating temperature range for the 25LC640A-H/SN?
The 25LC640A-H/SN is rated for operation from –40°C to +150°C (Extended H grade), fully qualified per AEC-Q100 for automotive under-hood applications. This specification is verified across voltage (2.5V–5.5V) and frequency (up to 5 MHz) ranges, with data retention guaranteed >200 years at +150°C. The "H" suffix explicitly denotes this extended temperature capability.
Does the 25LC640A-H/SN support page write operations, and what is its page size?
Yes, the 25LC640A-H/SN supports page write operations with a fixed page size of 32 bytes. Page writes allow up to 32 contiguous bytes to be loaded into the internal page buffer before initiating the 6 ms internal write cycle. Crossing a 32-byte boundary during a page write causes wraparound within the same physical page, so software must enforce alignment to avoid unintended overwrites.
How does hardware write protection work on the 25LC640A-H/SN?
Hardware write protection on the 25LC640A-H/SN requires both the WPEN bit (bit 7 of STATUS register) to be set to '1' and the WP pin (Pin 3) to be held low. When enabled, this configuration blocks writes to nonvolatile STATUS register bits (BP0, BP1, WPEN) but allows normal memory reads and writes. If WPEN = 0, the WP pin has no effect, enabling full STATUS register programmability regardless of WP pin state.
Is the 25LC640A-H/SN pin-compatible with other devices in the 25LCxxx family?
Yes, the 25LC640A-H/SN uses the standard 8-pin SOIC (SN) package and shares identical pinout, SPI protocol, instruction set, and electrical timing with all members of the 25LCxxx family (e.g., 25LC320A, 25LC128). This enables direct substitution within the same package footprint when density, page size, or temperature grade aligns with system requirements.
What is the endurance rating of the 25LC640A-H/SN, and how is it measured?
The 25LC640A-H/SN is specified for >1,000,000 erase/write cycles per memory location, measured under page-mode conditions at 25°C and VCC = 5.5V. This endurance value is ensured by characterization-not 100% tested-and reflects worst-case cycling across the full address space. Real-world endurance in automotive applications remains robust due to built-in wear leveling avoidance and deterministic write timing.
25LC640A-H/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm 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:
- 5 MHz
- Write Cycle Time - Word, Page:
- 6ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 150°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
25LC640A-H/SN FAQ
1.How can I place an order for 25LC640A-H/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC640A-H/SN 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 25LC640A-H/SN reliable?
The price and inventory of 25LC640A-H/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC640A-H/SN is usually 5 days.
3.What payment methods are accepted for 25LC640A-H/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC640A-H/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC640A-H/SN?
25LC640A-H/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC640A-H/SN 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 25LC640A-H/SN?
For technical support, including 25LC640A-H/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC640A-H/SN requirements.
6.How does Aetrix verify that 25LC640A-H/SN is sourced from the original manufacturer or authorized distributors?
All 25LC640A-H/SN 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 25LC640A-H/SN meets industry standards.
7.What is the process for return or replacement of 25LC640A-H/SN?
All 25LC640A-H/SN units undergo pre-shipment inspection (PSI). If there is an issue with 25LC640A-H/SN, 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 25LC640A-H/SN part is unused and in its original packaging.
Return procedure for 25LC640A-H/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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