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Microchip Technology 25C040/P
- Part No.:
- 25C040/P
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
25C040/P.pdf
- Description:
- IC EEPROM 4KBIT SPI 3MHZ 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:450
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Product details
Overview
25C040/P from Microchip Technology Inc. is a 4 Kbit (512 × 8) SPI-compatible serial EEPROM designed for nonvolatile data storage in embedded control and automotive systems. It operates at 4.5–5.5 V, supports up to 3 MHz clock frequency, features 16-byte page write capability, 5 ms max internal write cycle time, and automotive-grade temperature range (−40°C to +125°C). It is used in engine control units, battery management systems, and industrial sensor calibration storage.
For engineers reviewing the 25C040/P datasheet, 25C040/P pinout, 25C040/P application, or 25C040/P equivalent, this page delivers verified electrical specs, automotive-qualified timing behavior, hardware write protection logic, HOLD/CS/SO/SI/SCK/WP/VCC/VSS pin roles, and real-world EEPROM integration considerations for high-reliability designs.
Technical Context
The 25C040/P implements a standard SPI Mode 0,0 interface with separate SI (data-in) and SO (data-out) lines, requiring CS activation and SCK synchronization. Its architecture includes an 8-bit instruction register, internal address pointer, and STATUS register with WIP, WEL, BP0/BP1 bits for write status and block protection control.
It supports sequential read, byte/page write, RDSR/WRSR operations, and hardware-based data protection via WP pin assertion and power-on write-disable latch reset. All write cycles are self-timed and internally managed without external timing constraints beyond AC timing limits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit array), sufficient for firmware flags, calibration coefficients, or configuration registers in compact microcontroller systems |
| Supply voltage | 4.5–5.5 V - compatible with legacy 5 V logic rails and automotive 5 V supply domains |
| Max clock frequency | 3 MHz at VCC = 4.5–5.5 V - enables fast parameter loading without requiring high-speed MCU peripherals |
| Write cycle time | 5 ms maximum - defines minimum interval between successive page writes; impacts logging latency in real-time systems |
| Endurance & retention | 1 million erase/write cycles and >200 years data retention - validated for lifetime operation in automotive ECUs and industrial controllers |
| Temperature range | −40°C to +125°C (Automotive E grade) - qualified for under-hood and powertrain applications per AEC-Q100 stress requirements |
| ESD protection | >4000 V HBM - ensures robustness against handling and board-level electrostatic discharge events |
Pinout & Package
25C040/P is available in 8-pin PDIP (Plastic Dual In-line Package), with 300 mil body width and through-hole mounting. Pin 1 is CS (Chip Select), pin 2 is SO (Serial Output), pin 3 is WP (Write-Protect), pin 4 is VSS (Ground), pin 5 is SI (Serial Input), pin 6 is SCK (Serial Clock), pin 7 is HOLD (Hold Input), and pin 8 is VCC (Supply Voltage).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select input | Active-low enable signal; deselecting forces SO into high-impedance state and enters Standby mode (500 nA ICCS) |
| SO (Pin 2) | Serial Output | Data output line synchronized to SCK falling edge; tri-stated when CS high or HOLD low |
| WP (Pin 3) | Hardware write-protect | Low level disables all writes to memory and STATUS register; overrides WREN latch state |
| VSS (Pin 4) | Ground reference | Primary return path for all I/O and core logic; must be low-impedance connection in automotive PCB layouts |
| SI (Pin 5) | Serial Input | Instruction, address, and data input latched on SCK rising edge; supports MSB-first SPI framing |
| SCK (Pin 6) | Serial Clock | Master-generated clock synchronizing all SPI transactions; timing critical for AC compliance at 3 MHz |
| HOLD (Pin 7) | Communication suspend | Pauses ongoing SPI sequence without resetting internal state; requires SCK low before assertion |
| VCC (Pin 8) | Power supply | 4.5–5.5 V nominal supply; decoupling capacitor required near pin per automotive EMC guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Block write protection | Selectable protection of none / upper 1/4 / upper 1/2 / full array via BP0/BP1 bits - enables secure storage partitioning for boot code vs. runtime parameters |
| Self-timed write cycles | No external wait-state logic required; internal timing eliminates MCU polling overhead during 5 ms write completion |
| HOLD pin functionality | Enables interrupt servicing mid-transaction without losing SPI context - critical for deterministic response in real-time safety-critical firmware |
| Power-on data protection | Write enable latch resets at power-up and after WRDI/WRSR/program completion - prevents accidental writes during brown-out or reset recovery |
| Automotive temperature qualification | Validated operation from −40°C to +125°C - meets extended thermal requirements for engine control, transmission, and ADAS subsystems |
Applications
| Engine Control Unit (ECU) Calibration Storage | Industrial Sensor Configuration Memory |
|---|---|
Use Scenario: Storing fuel map coefficients, ignition timing offsets, and adaptive learning values that must survive vehicle shutdown and retain accuracy over 15+ years. IC Role / Device Role / Timing Role: Nonvolatile parameter store interfaced directly to PIC or dsPIC MCU via SPI; accessed during boot and periodic recalibration. Use Value: 1M endurance and >200-year retention ensure calibration integrity across full vehicle lifecycle without field updates. | Use Scenario: Holding factory-trimmed offset/gain values, linearization tables, and communication protocol settings for pressure/temperature sensors in factory automation equipment. IC Role / Device Role / Timing Role: SPI-configurable memory mapped by ARM Cortex-M4 host; written once at production test, read at power-on. Use Value: Hardware WP pin prevents runtime corruption during EMI-heavy plant-floor operation; 5 ms write time enables batch programming during test. |
| Automotive Body Control Module (BCM) Settings | Battery Management System (BMS) Fault Logs |
Use Scenario: Retaining user preferences (window position, mirror angle, lighting profiles) and diagnostic trouble codes (DTCs) across ignition cycles in BCMs. IC Role / Device Role / Timing Role: Low-power SPI EEPROM accessed intermittently by 8-bit MCU; standby current of 500 nA minimizes parasitic drain. Use Value: Automotive-grade −40°C to +125°C rating ensures reliable operation inside door modules and junction boxes exposed to ambient extremes. | Use Scenario: Recording cell voltage imbalances, thermal excursions, and overcurrent events for post-failure analysis in EV traction battery packs. IC Role / Device Role / Timing Role: Write-on-event memory triggered by BMS microcontroller; uses HOLD to pause logging during high-priority cell balancing interrupts. Use Value: HOLD pin preserves transaction state during 100+ μs interrupt latency, preventing log corruption without software re-synchronization. |
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 supply, 1 MHz max clock, Industrial (−40°C to +85°C) grade only | Lacks automotive temperature qualification and 3 MHz speed; suitable for commercial-grade consumer electronics | Select only if system operates below 85°C and uses 1.8–3.3 V logic; not drop-in for 25C040/P in automotive designs |
| 25LC040T-I/P | 2.5–5.5 V supply, 2 MHz max clock, Industrial grade only | Intermediate voltage and speed; no 125°C support; lower ESD rating (not specified as >4 kV) | Use where 2.5 V minimum rail exists and 125°C operation is unnecessary; verify WP/HOLD timing margins at 2.5 V |
Compared with 25AA040T-I/P and 25LC040T-I/P, the 25C040/P uniquely delivers 5 V compatibility, 3 MHz throughput, and AEC-Q100-aligned −40°C to +125°C operation - making it the only choice for legacy 5 V automotive modules requiring guaranteed high-temp reliability and fast parameter writes.
Availability
25C040/P is available at Aetrix Electronics and suitable for automotive control units, industrial sensor nodes, and battery management systems requiring stable component supply, long-term lifecycle support, and traceable sourcing for safety-critical applications.
Supply support for 25C040/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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25C040/P belongs to Microchip's legacy 25XX040 serial EEPROM product line, engineered specifically for 5 V automotive and industrial applications requiring high reliability, hardware write protection, and SPI interoperability with legacy MCUs.
FAQ
What is the maximum clock frequency supported by the 25C040/P?
The 25C040/P supports a maximum clock frequency of 3 MHz when operated within its specified VCC range of 4.5–5.5 V. This value is confirmed in Table 1-2 of the DS21204E datasheet under FCLK parameter for VCC = 4.5V to 5.5V. At lower supply voltages, the maximum clock rate decreases - e.g., 2 MHz at 2.5–4.5 V - but those conditions do not apply to the 25C040/P, which is rated exclusively for 4.5–5.5 V operation. The 25C040/P must not be operated outside this voltage window to guarantee 3 MHz timing compliance.
Does the 25C040/P support hardware write protection?
Yes, the 25C040/P provides dedicated hardware write protection via the WP (Write-Protect) pin (Pin 3). When WP is held low, all writes to both the memory array and STATUS register are disabled - even if the internal write-enable latch is set. This function is independent of software commands and remains active across power cycles. The 25C040/P datasheet explicitly confirms this behavior in Section 2.3 and Table 3-3, stating that WP low forces protected blocks and protected STATUS register regardless of WEL state. This makes the 25C040/P suitable for safety-critical storage where accidental firmware overwrite must be physically prevented.
What package type does the 25C040/P use?
The 25C040/P uses an 8-pin Plastic Dual In-line Package (PDIP) with 300 mil body width, as documented in Section 4.1 and Figure C04-018 of the DS21204E datasheet. 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. This through-hole package is intended for prototyping, legacy board assembly, and applications where socketing or manual rework is required. It is distinct from SOIC and TSSOP variants denoted by suffixes like "SN" or "ST".
Is the 25C040/P qualified for automotive applications?
Yes, the 25C040/P is explicitly qualified for automotive applications with an operating temperature range of −40°C to +125°C (E grade), as stated in the Device Selection Table on page 1 of DS21204E. This rating satisfies extended thermal requirements for under-hood and powertrain control modules. While not formally AEC-Q100 certified in this revision, its characterization across the full E-grade range - including endurance, retention, and AC timing validation at 125°C - aligns with automotive reliability expectations. The 25C040/P is the only member of the 25XX040 family specified for +125°C operation.
How many bytes can be written in a single page write operation on the 25C040/P?
The 25C040/P supports 16-byte page write operations, as specified in the Features section on page 1 of DS21204E. Each page spans addresses ending in 0000–1111 (i.e., aligned to 16-byte boundaries), and attempting to cross a page boundary during a single write sequence causes the internal address counter to roll over to the start of the same page - potentially overwriting previously written data. Therefore, firmware must enforce 16-byte alignment and limit burst writes to ≤16 bytes within one page. This constraint directly affects buffer management in host MCU drivers for the 25C040/P.
25C040/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:
- 3 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
25C040/P FAQ
1.How can I place an order for 25C040/P through Aetrix?
Please submit a Request for Quotation (RFQ) for 25C040/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 25C040/P reliable?
The price and inventory of 25C040/P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25C040/P is usually 5 days.
3.What payment methods are accepted for 25C040/P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25C040/P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25C040/P?
25C040/P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25C040/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 25C040/P?
For technical support, including 25C040/P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25C040/P requirements.
6.How does Aetrix verify that 25C040/P is sourced from the original manufacturer or authorized distributors?
All 25C040/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 25C040/P meets industry standards.
7.What is the process for return or replacement of 25C040/P?
All 25C040/P units undergo pre-shipment inspection (PSI). If there is an issue with 25C040/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 25C040/P part is unused and in its original packaging.
Return procedure for 25C040/P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25C040/P Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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AT24C08C-STUM-T
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