My Inquiry
My Account
Microchip Technology 25LC640/WF
- Part No.:
- 25LC640/WF
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- Die
- Datasheet:
-
25LC640/WF.pdf
- Description:
- IC EEPROM 64KBIT SPI 2MHZ DIE
- Quantity:
- Payment:
- Shipping:
Inventory:1,193
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
25LC640/WF from Microchip Technology Inc. is a 64 Kbit SPI Serial EEPROM with 8192 × 8-bit organization, 32-byte page write capability, and industrial temperature range (–40°C to +85°C). It operates at 2.5–5.5 V supply, supports up to 2 MHz clock frequency, and delivers ultra-low standby current of 500 nA - ideal for battery-backed data logging in embedded control systems.
For engineers reviewing the 25LC640/WF datasheet, 25LC640/WF pinout, 25LC640/WF application, or 25LC640/WF equivalent, this page provides verified electrical parameters, SPI timing constraints, hardware write-protection behavior, endurance (1 million cycles), and package-specific pin mapping for SOIC-8 (WF = SOIC package per Microchip's identification system).
Technical Context
The 25LC640/WF implements a standard SPI Mode 0,0 interface with separate SI (data in) and SO (data out) lines, CS-controlled selection, and HOLD pin for transaction suspension without reset. Its internal architecture includes a status register with WIP, WEL, BP0/BP1, and WPEN bits enabling configurable block protection (none/¼/½/all array) and hardware write-disable via WP pin.
It uses self-timed erase/write cycles (max 5 ms), supports sequential read with automatic address rollover, and integrates power-on data protection via write-enable latch reset and built-in voltage monitoring - ensuring reliable nonvolatile storage in power-critical applications without external supervision circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8192 × 8-bit), sufficient for firmware parameter tables or calibration data in resource-constrained microcontrollers |
| Interface | SPI-compatible serial bus (Mode 0,0), requiring only CS, SCK, SI, SO, HOLD, WP - minimal GPIO footprint |
| Max Clock Frequency | 2 MHz at VCC ≥ 2.5V; enables fast configuration loading in real-time systems |
| Write Cycle Time | 5 ms max internal write time; deterministic latency for critical save operations |
| Endurance | 1 million erase/write cycles - validated for high-frequency logging (e.g., sensor sampling every 100 ms) |
| Data Retention | >200 years at +25°C - ensures long-term reliability in unattended equipment |
| Supply Voltage Range | 2.5–5.5 V - compatible with 3.3 V and 5 V logic domains without level shifting |
| Standby Current | 500 nA typical - extends battery life in always-on IoT edge nodes |
Pinout & Package
25LC640/WF is supplied in an 8-pin SOIC package (150 mil body width), marked per Microchip's standard SOIC-8 pinout: Pin 1 = CS, Pin 2 = SO, Pin 3 = WP, Pin 4 = VSS, Pin 5 = SI, Pin 6 = SCK, Pin 7 = HOLD, Pin 8 = VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable; forces SO into high-impedance when deasserted, enabling multi-device SPI bus sharing |
| SO | Serial Data Output | Tri-state output updated on SCK falling edge; requires external pull-up for open-drain compatibility |
| WP | Write-Protect Input | Hardware lock for STATUS register when WPEN=1; prevents accidental firmware corruption during field updates |
| VSS | Ground Reference | Primary return path for all internal logic and memory array; must be low-impedance for stable read/write margins |
| SI | Serial Data Input | Latches instruction/address/data on SCK rising edge; tolerant of slow edges due to Schmitt-trigger input |
| SCK | Serial Clock Input | Synchronizes all SPI transactions; max 2 MHz rate defines minimum command execution time (~500 ns period) |
| HOLD | Transaction Pause Control | Halts ongoing SPI transfer while preserving internal state; allows host MCU to service higher-priority interrupts |
| VCC | Supply Voltage | 2.5–5.5 V operating range; internal voltage regulator enables consistent timing across rail variations |
Key Features
| Feature | Design Value |
|---|---|
| Block Write Protection | Configurable via STATUS register (BP0/BP1) to protect none, upper 1/4, upper 1/2, or entire 64 Kbit array - prevents overwrite of boot code or security keys |
| Hardware Write-Disable | WP pin + WPEN bit combination disables STATUS register writes even during active programming - eliminates risk of misconfigured protection |
| Hold Function | HOLD pin suspends SPI communication mid-sequence without resetting address pointer - preserves context during interrupt-driven host operation |
| Low-Power Operation | 500 nA standby current and 3 mA write current enable use in energy-harvesting or coin-cell-powered devices |
| High Reliability | ESD rating >4 kV HBM and >200-year data retention meet industrial equipment longevity requirements |
Applications
| Industrial Sensor Node | Medical Device Calibration Storage |
|---|---|
Use Scenario: Storing temperature-compensated sensor offsets and linearization coefficients in a wireless environmental monitor. IC Role / Device Role / Timing Role: Nonvolatile configuration storage accessed via SPI during boot and periodic recalibration; HOLD used to pause reads during RF transmission. Use Value: 32-byte page writes allow atomic update of multi-parameter calibration sets; 1M endurance supports daily recalibration over 27 years. | Use Scenario: Retaining factory-set calibration constants and usage logs in a portable blood glucose meter. IC Role / Device Role / Timing Role: Secure parameter storage with hardware WP enabled; STATUS register monitored to prevent concurrent access during measurement cycles. Use Value: WP pin grounding + WPEN=1 blocks unauthorized reprogramming; 500 nA standby current extends single-CR2032 battery life beyond 5 years. |
| PLC I/O Module Configuration | Smart Energy Meter Firmware Parameters |
Use Scenario: Holding channel-specific scaling factors and alarm thresholds in a DIN-rail mounted programmable logic controller module. IC Role / Device Role / Timing Role: SPI EEPROM interfaced to ARM Cortex-M4 host; CS toggled per parameter group; RDSR polled to confirm write completion before next command. Use Value: Block protection (BP1/BP0=1,1) locks critical safety thresholds; 2 MHz interface enables full 64 Kbit reload in <100 ms during firmware upgrade. | Use Scenario: Storing tariff schedules, demand-response settings, and tamper-event timestamps in ANSI C12.22-compliant electricity meters. IC Role / Device Role / Timing Role: High-reliability data logger with sequential read for rapid parameter fetch; HOLD asserted during metrology interrupt servicing. Use Value: >200-year data retention satisfies utility 20+ year deployment mandates; SO tri-state behavior prevents bus contention with other SPI peripherals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA640-I/SN | Wider VCC range (1.8–5.5 V); supports 1 MHz up to 1.8 V; identical pinout and timing | Better suited for 1.8 V logic systems or mixed-voltage designs where 25LC640/WF's 2.5 V min would require level translation | Select 25AA640-I/SN if operating below 2.5 V or needing guaranteed 1 MHz performance at 1.8 V. |
| 25LC640A-I/SN | Enhanced revision with improved ESD robustness (>6 kV HBM); same electrical specs and pin compatibility | Preferred for new designs requiring extended lifecycle support and higher immunity to handling damage | Choose 25LC640A-I/SN for production builds where long-term availability and enhanced reliability are prioritized. |
Compared with 25LC640/WF, 25AA640-I/SN offers lower-voltage flexibility but reduced speed at 1.8 V, while 25LC640A-I/SN provides identical functionality with upgraded process reliability - making it the recommended drop-in replacement for new designs.
Availability
25LC640/WF is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, PLC I/O module configuration, and smart energy meter firmware parameter management requiring stable component supply across extended product lifecycles.
Supply support for 25LC640/WF 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 memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25LC640 belongs to Microchip's serial EEPROM product line, engineered for robust, low-power nonvolatile data storage in industrial, automotive, and medical applications where SPI interface simplicity and long-term data integrity are critical.
FAQ
What is the maximum clock frequency supported by the 25LC640/WF?
The 25LC640/WF supports up to 2 MHz clock frequency when VCC is 2.5 V or higher. At VCC = 4.5–5.5 V, it can operate at 3 MHz in industrial temperature range, but datasheet DS21223H specifies 2 MHz as the guaranteed maximum for the 25LC640 variant. This timing constraint directly affects command throughput - for example, a full 64 Kbit read completes in under 260 ms at 2 MHz.
Does the 25LC640/WF support hardware write protection?
Yes, the 25LC640/WF supports hardware write protection via its WP pin combined with the WPEN bit in the STATUS register. When WP is held low and WPEN = 1, writes to nonvolatile STATUS register bits are disabled - preventing accidental changes to block protection settings. This dual-control mechanism ensures that critical configuration data remains immutable even during firmware updates.
What package type does the /WF suffix indicate for the 25LC640/WF?
The /WF suffix in 25LC640/WF denotes Microchip's standard 8-pin SOIC package (150 mil body width), also designated as /SN in their part numbering system. This package has a 1.27 mm pitch, surface-mount footprint, and is RoHS-compliant. Pin 1 is CS, Pin 2 is SO, Pin 3 is WP, Pin 4 is VSS, Pin 5 is SI, Pin 6 is SCK, Pin 7 is HOLD, and Pin 8 is VCC - matching industry-standard SOIC-8 layout.
How many write/erase cycles is the 25LC640/WF rated for?
The 25LC640/WF is rated for 1 million write/erase cycles per memory location, as specified in Table 1-2 Note 3 of DS21223H. This endurance level is established through characterization and supports applications such as daily parameter logging for over 27 years. Real-world wear leveling is not implemented internally, so system-level software must avoid repeated writes to fixed addresses to achieve rated lifetime.
Can the 25LC640/WF be used in automotive applications?
The base 25LC640/WF is qualified for industrial temperature range (–40°C to +85°C) only. While Microchip offers an automotive-grade variant (25LC640-E/ST) rated to +125°C, the /WF suffix specifically identifies the SOIC package in industrial grade. Using 25LC640/WF in under-hood automotive environments exceeds its specified operating limits and risks data retention failure or parametric shift.
25LC640/WF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- Die
- Packaging:
- Tray
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 64Kbit
- Memory Organization:
- 8K x 8
- Memory Interface:
- SPI
- Clock Frequency:
- 2 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- Die
25LC640/WF FAQ
1.How can I place an order for 25LC640/WF through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC640/WF 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 25LC640/WF reliable?
The price and inventory of 25LC640/WF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC640/WF is usually 5 days.
3.What payment methods are accepted for 25LC640/WF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC640/WF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC640/WF?
25LC640/WF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC640/WF 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 25LC640/WF?
For technical support, including 25LC640/WF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC640/WF requirements.
6.How does Aetrix verify that 25LC640/WF is sourced from the original manufacturer or authorized distributors?
All 25LC640/WF 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 25LC640/WF meets industry standards.
7.What is the process for return or replacement of 25LC640/WF?
All 25LC640/WF units undergo pre-shipment inspection (PSI). If there is an issue with 25LC640/WF, 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 25LC640/WF part is unused and in its original packaging.
Return procedure for 25LC640/WF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25LC640/WF Tags
-
M24C02-WMN6TP
STMicroelectronics
-
AT24C02C-XHM-T
Microchip Technology
-
AT21CS01-STUM10-T
Microchip Technology
-
AT24C02C-SSHM-T
Microchip Technology
-
24LC01BT-I/OT
Microchip Technology
-
M24C02-FMC6TG
STMicroelectronics
-
AT24CS02-SSHM-T
Microchip Technology
-
93LC46BT-I/OT
Microchip Technology
-
AT24C04C-SSHM-T
Microchip Technology
-
24LC01BT-I/SN
Microchip Technology
-
24AA02UIDT-I/OT
Microchip Technology
-
AT24C08C-STUM-T
Microchip Technology
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
