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Microchip Technology 25LC040/P
- Part No.:
- 25LC040/P
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
25LC040/P.pdf
- Description:
- IC EEPROM 4KBIT SPI 2MHZ 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:555
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Product details
Overview
25LC040/P from Microchip Technology Inc. is a 4 Kbit (512 × 8) SPI-compatible serial EEPROM with 2.5–5.5 V supply range, 2 MHz max clock frequency, and industrial temperature rating (–40°C to +85°C). It features hardware write protection (WP), HOLD suspend functionality, and 16-byte page write capability - deployed in embedded systems for firmware parameter storage, calibration data retention, and configuration backup.
For engineers reviewing the 25LC040/P datasheet, 25LC040/P pinout, 25LC040/P application, or 25LC040/P equivalent, key selection criteria include VCC operating range compatibility, SPI timing margins at 2 MHz, WP/HOLD signal integration, and endurance requirements for field-updatable systems.
Technical Context
The 25LC040/P implements a standard SPI Mode 0,0 interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, SI, SO, WP, HOLD, VCC, and VSS. Its internal architecture includes an 8-bit instruction register, auto-incrementing address pointer, and STATUS register with WIP/WEL/BP bits for real-time write status and block protection control.
Write operations are gated by both the volatile write-enable latch (set via WREN) and the hardware WP pin; self-timed internal write cycles complete in ≤5 ms, and sequential reads roll over from address 01FFh to 0000h. Block protection supports four configurations: none, upper 1/4 (0180h–01FFh), upper 1/2 (0100h–01FFh), or full array (0000h–01FFh).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit array), sufficient for small firmware patches or device-specific configuration sets |
| Interface | SPI Mode 0,0 (CPOL=0, CPHA=0) with dedicated SI/SO lines - no shared bidirectional data line required |
| Max clock frequency | 2 MHz at VCC ≥ 2.5 V - enables fast read/write in microcontroller-based systems with moderate bus loading |
| Write cycle time | ≤5 ms internal self-timed erase/write - eliminates need for external timeout logic or polling overhead beyond WIP bit check |
| Endurance & retention | 1 million write/erase cycles and >200 years data retention - validated for long-life industrial logging and calibration storage |
| VCC range | 2.5–5.5 V - compatible with 3.3 V and 5 V logic domains without level shifting |
| Operating temperature | –40°C to +85°C (Industrial grade) - qualified for deployment in non-automotive embedded control environments |
Pinout & Package
8-pin PDIP (300 mil) package with through-hole mounting; 0.300" width, 0.373" length, 0.130" thickness; JEDEC MS-001 compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select input | Active-low enable: pulls device out of standby; rising edge after write sequence initiates internal write cycle |
| SO (Pin 2) | Serial Output | Data-out only; tri-states when CS high or HOLD low - enables multi-device SPI bus sharing |
| WP (Pin 3) | Write-Protect input | Hardware lock: disables all writes to memory and STATUS register when low; overrides WREN state |
| VSS (Pin 4) | Ground reference | Return path for all I/O and core logic; must be low-impedance connection to system GND plane |
| SI (Pin 5) | Serial Input | Data-in only; latches instruction/address/data on SCK rising edge - no internal pull-up/pull-down |
| SCK (Pin 6) | Serial Clock input | Synchronizes all transfers; rising edge clocks SI, falling edge updates SO - requires monotonic edges |
| HOLD (Pin 7) | Communication suspend | Pauses ongoing SPI sequence without reset; SO goes high-Z; resumes from exact byte position on HOLD high |
| VCC (Pin 8) | Supply voltage | 2.5–5.5 V power input; decoupling capacitor (0.1 μF ceramic) required within 10 mm of pin |
Key Features
| Feature | Design Value |
|---|---|
| 16-byte page write | Enables burst programming of up to 16 contiguous bytes per write cycle - reduces total write time vs. byte-by-byte |
| Block write protection | Configurable via STATUS register (BP1/BP0): protects none, upper 1/4, upper 1/2, or entire 512-byte array |
| Power-on write disable | Write enable latch resets at power-up; prevents inadvertent writes during brown-out or cold-start conditions |
| Low-power operation | 500 nA standby current and 500 μA active read current - suitable for battery-backed or energy-constrained nodes |
| HOLD suspend mode | Allows host MCU to service higher-priority interrupts mid-transfer without losing SPI context or reinitializing sequence |
Applications
| Industrial Sensor Node | Medical Device Calibration |
|---|---|
Use Scenario: Storing sensor offset/gain coefficients and runtime fault logs in a wireless temperature/humidity node. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed via SPI during boot and periodic calibration updates. Use Value: 1M endurance ensures >10 years of daily recalibration cycles; 200-year retention guarantees data integrity across product lifetime. |
Use Scenario: Retaining factory-set calibration constants and user-adjusted therapy parameters in portable infusion pumps. IC Role / Device Role / Timing Role: Secure, WP-protected memory for safety-critical settings that must survive power loss and ESD events. Use Value: Hardware WP pin prevents accidental overwrite during firmware updates; >4 kV ESD rating meets IEC 61000-4-2 Level 4 requirements. |
| Smart Energy Meter | PLC I/O Module |
Use Scenario: Recording tariff schedules, demand-response commands, and tamper-event timestamps in ANSI C12.20-compliant meters. IC Role / Device Role / Timing Role: SPI EEPROM interfaced to metering SoC for secure, timestamped event logging and firmware patch storage. Use Value: 2 MHz SPI speed enables rapid log writes during peak load events; industrial temp range supports outdoor meter enclosures. |
Use Scenario: Holding module identification, channel configuration, and diagnostic history in DIN-rail mounted I/O expansion units. IC Role / Device Role / Timing Role: Configuration memory mapped to controller's SPI peripheral for plug-and-play module recognition. Use Value: HOLD pin allows PLC CPU to pause EEPROM access during cyclic interrupt servicing - maintains deterministic scan times. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA040T-I/P | 1.8–5.5 V VCC range; 1 MHz max clock; same 8-pin PDIP package and pinout | Better suited for mixed-voltage systems with 1.8 V logic; lower speed margin acceptable for infrequent config writes | Select when wider supply flexibility is needed and 2 MHz timing is not required |
| AT25040B-PU | 4 Kbit SPI EEPROM; 1.8–5.5 V; 20 MHz max clock; same PDIP-8 footprint but different pin mapping (SO/SI swapped) | Higher-speed interface available; requires PCB layout change due to SI/SO pin swap vs. 25LC040/P | Choose only if board redesign is feasible and >2 MHz throughput is critical |
Compared with 25AA040T-I/P and AT25040B-PU, the 25LC040/P offers optimal balance of 2 MHz performance, 2.5–5.5 V compatibility, and drop-in PDIP-8 placement - making it ideal for legacy 3.3 V/5 V industrial controllers where pinout stability and proven reliability are prioritized over ultra-high speed or ultra-low voltage operation.
Availability
25LC040/P is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, smart energy metering, and PLC I/O modules requiring stable component supply and long-term obsolescence management.
Supply support for 25LC040/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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and memory products for embedded control applications.
The 25LC040/P belongs to Microchip's legacy 25XX040 serial EEPROM family, designed specifically for reliable, low-power, SPI-based nonvolatile storage in cost-sensitive industrial and commercial equipment.
FAQ
What is the maximum clock frequency supported by the 25LC040/P?
The 25LC040/P supports a maximum SPI clock frequency of 2 MHz when VCC is ≥2.5 V. This specification is validated across the full industrial temperature range (–40°C to +85°C) and enables efficient data transfer in microcontroller-based systems without requiring external clock dividers or timing compensation.
Does the 25LC040/P require external pull-up resistors on its SPI lines?
The 25LC040/P does not integrate internal pull-up or pull-down resistors on SI, SO, SCK, CS, WP, or HOLD pins. External pull-ups are recommended on CS and WP for robust noise immunity in noisy industrial environments, while SO may require a pull-up if driving long traces or multiple loads - per Microchip's layout guidelines in DS21204E.
How does the HOLD function operate during an active SPI transaction on the 25LC040/P?
When HOLD is pulled low during an active SPI sequence, the 25LC040/P immediately suspends communication: SO enters high-impedance, and SI/SCK inputs are ignored. The device retains full context (address pointer, instruction state) and resumes precisely where it left off upon HOLD returning high - enabling deterministic interrupt handling in real-time systems using the 25LC040/P.
Can the 25LC040/P be used in a 1.8 V system?
No - the 25LC040/P has a minimum VCC rating of 2.5 V and is not specified for operation below that threshold. For 1.8 V systems, Microchip recommends the 25AA040 series (e.g., 25AA040T-I/P), which is explicitly characterized down to 1.8 V and shares identical pinout and instruction set with the 25LC040/P.
What is the purpose of the Write-Protect (WP) pin on the 25LC040/P?
The WP pin on the 25LC040/P provides hardware-level write inhibition: when held low, it disables all writes to both memory array and STATUS register regardless of WREN state or software commands. This ensures fail-safe protection against corruption during power transitions, firmware bugs, or ESD events - a critical feature for safety- and mission-critical deployments of the 25LC040/P.
25LC040/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:
- 4Kbit
- Memory Organization:
- 512 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
25LC040/P FAQ
1.How can I place an order for 25LC040/P through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC040/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 25LC040/P reliable?
The price and inventory of 25LC040/P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC040/P is usually 5 days.
3.What payment methods are accepted for 25LC040/P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC040/P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC040/P?
25LC040/P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC040/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 25LC040/P?
For technical support, including 25LC040/P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC040/P requirements.
6.How does Aetrix verify that 25LC040/P is sourced from the original manufacturer or authorized distributors?
All 25LC040/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 25LC040/P meets industry standards.
7.What is the process for return or replacement of 25LC040/P?
All 25LC040/P units undergo pre-shipment inspection (PSI). If there is an issue with 25LC040/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 25LC040/P part is unused and in its original packaging.
Return procedure for 25LC040/P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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