My Inquiry
My Account
Microchip Technology 25LC640-I/P
- Part No.:
- 25LC640-I/P
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
25LC640-I/P.pdf
- Description:
- IC EEPROM 64KBIT SPI 2MHZ 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,739
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
25LC640-I/P 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 from 2.5V–5.5V VCC, supports up to 2 MHz clock frequency, and delivers 5 ms max internal write cycle time. It is used for nonvolatile parameter storage in microcontroller-based embedded systems requiring low-power, reliable data retention.
For engineers reviewing the 25LC640-I/P datasheet, 25LC640-I/P pinout, 25LC640-I/P application, or 25LC640-I/P equivalent, key selection criteria include SPI interface compatibility, write-protection granularity (none/¼/½/all), hold functionality for interrupt servicing, standby current (500 nA typical), and PDIP-8 package suitability for prototyping and legacy board designs.
Technical Context
The 25LC640-I/P implements a standard SPI Mode 0,0 (CPOL=0, CPHA=0) serial interface with separate SI (data in) and SO (data out) lines, CS-controlled device selection, and HOLD pin for pausing ongoing transfers without sequence reset. Its internal architecture includes an 8-bit instruction register, STATUS register with WIP/WEL/BP0/BP1 bits, and hardware write protection enabled via WP pin and WPEN bit.
It features self-timed erase/write cycles, block write protection covering configurable memory segments (0x0000–0x1FFF), sequential read with automatic address rollover, and built-in power-on data protection via write-enable latch reset. Endurance is rated at 1 million erase/write cycles, with >200 years data retention under industrial conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 64 Kbit (8192 × 8-bit), enabling storage of firmware parameters, calibration data, or configuration settings in resource-constrained systems |
| Interface | SPI-compatible serial bus (Mode 0,0), requiring only CS, SCK, SI, SO - simplifies MCU integration and reduces PCB routing complexity |
| VCC range | 2.5V to 5.5V, supporting direct connection to 3.3V or 5V logic domains without level-shifting circuitry |
| Max clock frequency | 2 MHz (at VCC ≥ 2.5V), enabling ~256 KB/s effective read throughput for rapid configuration loading |
| Write cycle time | 5 ms maximum per page (up to 32 bytes), defining worst-case latency for persistent state updates |
| Standby current | 500 nA typical, critical for battery-powered devices where quiescent power must be minimized between writes |
| Data retention | >200 years at +85°C, ensuring long-term reliability in industrial control and metering applications |
| Endurance | 1 million erase/write cycles, supporting frequent logging or counter increment operations over product lifetime |
Pinout & Package
25LC640-I/P is supplied in an 8-pin Plastic Dual In-line Package (PDIP) with 300-mil body width, suitable for through-hole prototyping, socket-based testing, and legacy industrial PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select input | Active-low enable signal; deselecting places SO in high-impedance state, allowing multi-device SPI bus sharing |
| SO (Pin 2) | Serial Output | Tri-state output delivering read data on falling edge of SCK; enters high-Z when CS is high or HOLD is asserted |
| WP (Pin 3) | Write-Protect input | Hardware lock for STATUS register when WPEN=1; grounded to prevent accidental writes during power transitions |
| VSS (Pin 4) | Ground reference | Primary return path for all internal circuitry and I/O signals; must be low-impedance for noise immunity |
| SI (Pin 5) | Serial Input | Accepts instructions, addresses, and write data on rising edge of SCK; latched synchronously for timing robustness |
| SCK (Pin 6) | Serial Clock input | Master-generated clock synchronizing all SPI transactions; rise/fall times ≤2 μs required for reliable operation |
| HOLD (Pin 7) | Hold input | Pauses active SPI transfer without resetting state; allows host MCU to service higher-priority interrupts mid-sequence |
| VCC (Pin 8) | Supply voltage | Power source for core logic and EEPROM array; bypass capacitor (0.1 μF) recommended near pin for transient suppression |
Key Features
| Feature | Design Value |
|---|---|
| Page write capability | 32-byte burst writes within same page boundary (e.g., 0x0000–0x001F), reducing total write cycles needed for multi-byte updates |
| Configurable block protection | BP0/BP1 bits allow selective write-lock of none, upper 1/4 (0x1800–0x1FFF), upper 1/2 (0x1000–0x1FFF), or full array (0x0000–0x1FFF) |
| HOLD function | Enables interruption of ongoing SPI reads/writes without losing position; resumes from exact byte count upon HOLD deassertion |
| Power-on write protection | Write enable latch resets at power-up, preventing spurious writes during supply ramp; explicit WREN instruction required before any write |
| Low-voltage operation | Functional down to 2.5V VCC, enabling use in brown-out tolerant systems and mixed-voltage designs without regulators |
| ESD robustness | >4000V HBM rating ensures resilience against handling and system-level ESD events in industrial environments |
Applications
| Industrial Sensor Calibration | Medical Device Configuration |
|---|---|
|
Use Scenario: Storing factory-calibrated sensor offset/gain coefficients and user-adjusted trim values in programmable pressure or temperature transmitters. IC Role / Device Role / Timing Role: Nonvolatile parameter storage element interfaced to an 8-bit or 16-bit MCU via SPI; accessed during boot and on-demand recalibration. Use Value: Enables field-upgradable calibration without firmware changes; 500 nA standby current extends battery life in wireless sensor nodes. |
Use Scenario: Retaining patient-specific therapy settings, device ID, and usage logs in portable infusion pumps or diagnostic handhelds. IC Role / Device Role / Timing Role: Secure configuration store with hardware write-protection (WP pin + BP bits) to prevent unauthorized parameter modification. Use Value: Meets IEC 62304 safety requirements by isolating critical settings from runtime software faults; >200-year data retention ensures lifetime validity. |
| Automotive Body Control Module | Smart Energy Metering |
|
Use Scenario: Saving seat/mirror position presets, lighting profiles, and error codes in 12V automotive BCMs operating across −40°C to +85°C. IC Role / Device Role / Timing Role: SPI EEPROM co-located with MCU for fast access to user preferences; HOLD pin used to pause writes during CAN interrupt handling. Use Value: Industrial temp grade and 2.5V–5.5V operation tolerate automotive battery fluctuations; 1M endurance supports daily reprogramming over 10+ years. |
Use Scenario: Recording tariff schedules, tamper events, and accumulated kWh in ANSI C12.20-compliant electricity meters with 10+ year field life. IC Role / Device Role / Timing Role: High-reliability data logger storing time-stamped events; write-protected status bits prevent corruption of billing-critical registers. Use Value: 5 ms write time enables rapid event capture during power loss; >200-year retention exceeds utility deployment mandates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SPI EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA640-I/P | 1.8V–5.5V VCC, 1 MHz max clock, identical 8192×8 organization and PDIP-8 package | Broader voltage range enables direct use with 1.8V MCUs; lower speed acceptable where throughput not critical | Select when interfacing with low-voltage microcontrollers or where 1 MHz SPI bandwidth suffices |
| 25LC640-I/SN | Same electrical specs and functionality, but in 8-lead SOIC (150-mil) surface-mount package | SOIC variant targets automated assembly and space-constrained PCBs; no through-hole mounting support | Choose for volume production with pick-and-place; avoid if manual prototyping or socketing required |
Compared with 25AA640-I/P and 25LC640-I/SN, the 25LC640-I/P offers optimal trade-off of 2 MHz speed and PDIP-8 mechanical compatibility for development and industrial retrofits, while maintaining identical memory architecture and protection features.
Availability
25LC640-I/P is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control modules, and smart energy metering requiring stable component supply and long-term obsolescence management.
Supply support for 25LC640-I/P 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 components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing infrastructure.
The 25LC640 belongs to Microchip's legacy SPI Serial EEPROM product line, designed specifically for cost-sensitive, low-power embedded systems needing reliable nonvolatile storage with simple serial interface and robust data integrity features.
FAQ
What is the maximum SPI clock frequency supported by the 25LC640-I/P?
The 25LC640-I/P supports up to 2 MHz SPI clock frequency when VCC is 2.5V or higher. At VCC = 4.5–5.5V, it can operate up to 3 MHz, but the industrial-grade 25LC640-I/P variant is specified for 2 MHz maximum per the DS21223H datasheet. This defines the upper limit for reliable read/write timing margins in your MCU firmware.
How does the HOLD pin function during an active SPI transaction on the 25LC640-I/P?
The HOLD pin on the 25LC640-I/P suspends ongoing SPI communication without resetting the internal address pointer or command state. When pulled low while SCK is low, SI/SO/SCK enter high-impedance and are ignored until HOLD is raised again with SCK low. This allows the host MCU to service urgent interrupts and resume exactly where it left off - a key feature confirmed in Section 2.6 of the 25LC640-I/P datasheet.
Can the 25LC640-I/P be used with a 1.8V microcontroller?
No, the 25LC640-I/P requires a minimum VCC of 2.5V and is not guaranteed to operate correctly at 1.8V. For 1.8V systems, Microchip specifies the 25AA640-I/P instead, which supports 1.8V–5.5V operation. Using 25LC640-I/P below 2.5V may result in unreliable reads, failed writes, or undefined STATUS register behavior.
What write protection options are available on the 25LC640-I/P?
The 25LC640-I/P provides dual-layer write protection: (1) hardware via the WP pin (when WPEN=1 in STATUS register), and (2) software-configurable block protection using BP0/BP1 bits to lock none, upper 1/4, upper 1/2, or the entire 64 Kbit array. These features are fully documented in Tables 3-2 and 3-3 of the 25LC640-I/P datasheet and operate independently of VCC level.
Is the 25LC640-I/P still recommended for new designs?
No - Microchip explicitly states "Not recommended for new designs" in DS21223H (Revision H, June 2008), advising migration to the enhanced 25LC640A or 25AA640A variants. These successors offer improved AC characteristics, updated qualification, and extended lifecycle support, while maintaining pin and functional compatibility with the 25LC640-I/P.
25LC640-I/P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- 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:
- 2 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
25LC640-I/P FAQ
1.How can I place an order for 25LC640-I/P through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC640-I/P 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-I/P reliable?
The price and inventory of 25LC640-I/P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC640-I/P is usually 5 days.
3.What payment methods are accepted for 25LC640-I/P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC640-I/P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC640-I/P?
25LC640-I/P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC640-I/P 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-I/P?
For technical support, including 25LC640-I/P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC640-I/P requirements.
6.How does Aetrix verify that 25LC640-I/P is sourced from the original manufacturer or authorized distributors?
All 25LC640-I/P 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-I/P meets industry standards.
7.What is the process for return or replacement of 25LC640-I/P?
All 25LC640-I/P units undergo pre-shipment inspection (PSI). If there is an issue with 25LC640-I/P, 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-I/P part is unused and in its original packaging.
Return procedure for 25LC640-I/P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25LC640-I/P 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…
