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Microchip Technology 25C040T/SN
- Part No.:
- 25C040T/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
25C040T/SN.pdf
- Description:
- IC EEPROM 4KBIT SPI 3MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,931
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Product details
Overview
25C040T/SN from Microchip Technology Inc. is a 4 Kbit (512 × 8) SPI serial EEPROM designed for nonvolatile data storage in automotive and industrial control 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 offers automotive-grade temperature range (−40°C to +125°C).
For engineers reviewing the 25C040T/SN datasheet, 25C040T/SN pinout, 25C040T/SN application, or 25C040T/SN equivalent, key selection criteria include its automotive temperature rating, hardware write-protect (WP) and hold (HOLD) functions, block protection configuration (BP0/BP1), and compatibility with standard SPI master interfaces requiring CS/SI/SO/SCK timing compliance.
Technical Context
The 25C040T/SN implements a standard SPI Mode 0,0 or Mode 1,1 interface with separate SI (data in) and SO (data out) lines, controlled by CS, SCK, WP, and HOLD signals. Its internal architecture includes an 8-bit instruction register, STATUS register with WIP/WEL/BP bits, and page-based write logic enforcing 16-byte alignment within 512-byte memory space.
It integrates power-on reset circuitry that clears the write enable latch, built-in write-protection via WP pin assertion, and automatic roll-over during sequential read. Write operations require explicit WREN instruction followed by CS high transition to initiate self-timed erase-and-write cycles - no external timing control needed.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit array), sufficient for firmware parameter storage or calibration data in ECUs |
| Interface | SPI-compatible serial bus (CS, SCK, SI, SO), no I²C or UART required |
| Max clock frequency | 3 MHz at VCC = 4.5–5.5 V, enabling fast configuration reads in real-time systems |
| Write cycle time | 5 ms maximum internal self-timed write, eliminating need for host polling delay management |
| Endurance & retention | 1 million write/erase cycles and >200 years data retention, validated for long-life automotive deployment |
| Temperature range | −40°C to +125°C (Automotive E grade), qualified for under-hood and transmission control environments |
| VCC operating range | 4.5 V to 5.5 V only, ensuring stable operation in 5 V rail systems without low-voltage brownout risk |
Pinout & Package
25C040T/SN is supplied in 8-pin SOIC (SN) package - narrow body, 150 mil width, JEDEC MS-012 compliant, tape-and-reel format (T suffix). 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; pin 8 is VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select input | Active-low enable: drives device into active mode; high state forces standby and tri-states SO for bus sharing |
| SO (Pin 2) | Serial output | Data-out line synchronized to SCK falling edge; high-impedance when CS high or HOLD low |
| WP (Pin 3) | Hardware write-protect | Low = all writes disabled (array + STATUS); high = normal operation; overrides WREN latch if pulled low mid-cycle |
| VSS (Pin 4) | Ground reference | Return path for all internal circuits; must be connected before VCC for proper power sequencing |
| SI (Pin 5) | Serial input | Data-in line synchronized to SCK rising edge; accepts instructions, addresses, and write data MSB-first |
| SCK (Pin 6) | Serial clock input | Master-generated clock; rising edge latches SI, falling edge updates SO; max 3 MHz at 4.5–5.5 V |
| HOLD (Pin 7) | Communication suspend | Low = pauses ongoing SPI sequence without reset; SO/SI/SCK go high-Z; resumes on HOLD high while SCK low |
| VCC (Pin 8) | Supply voltage | 4.5–5.5 V only; powers EEPROM core, logic, and HV generator; not 1.8 V or 2.5 V compatible |
Key Features
| Feature | Design Value |
|---|---|
| Block write protection | Configurable via STATUS register (BP1/BP0) to protect none, upper 1/4, upper 1/2, or entire 512-byte array |
| Hardware write-enable latch | Must be set via WREN instruction before any write; automatically cleared after WRITE, WRSR, WRDI, power-up, or WP low |
| Hold function | Enables interruption of multi-byte SPI transfers (e.g., during MCU interrupt servicing) without losing sequence context |
| Power-on data protection | Write enable latch resets at power-up; WP pin and internal circuitry prevent spurious writes during supply ramp |
| Page write capability | Up to 16 bytes written per command within same 16-byte page boundary, reducing SPI transaction overhead vs. byte writes |
Applications
| Engine Control Unit (ECU) | Transmission Control Module (TCM) |
|---|---|
Use Scenario: Storing adaptive learning parameters, fault codes, and calibration offsets that persist across ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced directly to MCU SPI port; accessed during boot and runtime diagnostics. Use Value: Automotive temperature rating (−40°C to +125°C) and 1M endurance ensure reliable logging over 15+ year vehicle lifetime. | Use Scenario: Retaining gear-shifting profiles and torque-map coefficients updated during vehicle learning phases. IC Role / Device Role / Timing Role: SPI EEPROM used for field-updatable lookup tables; accessed via deterministic timing-critical reads during shift events. Use Value: 3 MHz max clock and 5 ms write time enable fast reconfiguration without disrupting real-time control loops. |
| Body Control Module (BCM) | Advanced Driver Assistance Systems (ADAS) |
Use Scenario: Saving user preferences (mirror position, seat settings) and door-lock configuration states. IC Role / Device Role / Timing Role: Low-power serial memory holding persistent settings; accessed infrequently but requiring guaranteed retention. Use Value: 500 nA standby current and >200-year data retention eliminate battery drain concerns in always-on modules. | Use Scenario: Storing camera calibration data and sensor fusion coefficients updated during factory or dealer service. IC Role / Device Role / Timing Role: Secure, tamper-resistant storage for safety-critical configuration; write-protected via WP pin and BP bits. Use Value: Hardware write-protection (WP) and configurable block protection prevent accidental or malicious overwrite of calibrated values. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25C040T/ST | TSSOP-8 package (4.4 mm width); identical electrical specs and pinout mapping but different physical footprint | Used where board space is constrained and TSSOP thermal/mechanical profile is preferred over SOIC | Select 25C040T/ST only when layout requires TSSOP; verify PCB land pattern and reflow profile compatibility |
| 25AA040T/SN | 1.8–5.5 V VCC range; 1 MHz max clock; Industrial temp only (−40°C to +85°C); same SOIC-8 package | Targeted at cost-sensitive industrial controllers where 5 V rail stability is not guaranteed | Choose 25AA040T/SN only if wide VCC range or lower clock speed suffices; not suitable for automotive E-grade requirement |
Compared with 25C040T/SN, 25C040T/ST offers identical functionality in a smaller TSSOP package but requires PCB redesign, while 25AA040T/SN supports wider voltage range and lower cost but lacks automotive temperature qualification and 3 MHz performance - making it unsuitable for under-hood deployment.
Availability
25C040T/SN is available at Aetrix Electronics and suitable for engine control units, transmission control modules, and body control modules requiring stable component supply across extended automotive lifecycles.
Supply support for 25C040T/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 microcontroller, analog, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25C040 series belongs to Microchip's legacy SPI EEPROM product line, engineered specifically for automotive and industrial applications demanding high reliability, extended temperature operation, and robust hardware-level write protection.
FAQ
What is the operating voltage range for the 25C040T/SN?
The 25C040T/SN operates strictly within 4.5 V to 5.5 V. It is not compatible with 1.8 V or 2.5 V supply rails. This fixed 5 V range ensures noise immunity and compatibility with legacy automotive 5 V microcontrollers, but excludes use in low-voltage portable or battery-powered systems. Always verify VCC stability before initiating any SPI transaction on the 25C040T/SN.
Does the 25C040T/SN support SPI Mode 0,0 and Mode 1,1?
Yes, the 25C040T/SN supports both SPI Mode 0,0 (CPOL = 0, CPHA = 0) and Mode 1,1 (CPOL = 1, CPHA = 1), as confirmed in the AC characteristics and timing diagrams of DS21204E. The device samples SI on the rising edge of SCK and updates SO on the falling edge - behavior consistent with both modes depending on master clock polarity and phase configuration. This dual-mode support simplifies integration with diverse MCU families.
How does the HOLD pin function during an active SPI transfer on the 25C040T/SN?
The HOLD pin on the 25C040T/SN suspends an ongoing SPI sequence without resetting internal state. When pulled low while SCK is low, SI/SO/SCK enter high-impedance, and the device pauses mid-transfer. Resuming requires bringing HOLD high while SCK remains low. This allows the host MCU to service higher-priority interrupts and resume communication exactly where it left off - a critical feature for deterministic real-time systems using the 25C040T/SN.
Can the 25C040T/SN be used as a direct replacement for the 25LC040T/SN?
No, the 25C040T/SN is not a direct replacement for the 25LC040T/SN. While both share pinout and instruction set, the 25C040T/SN requires 4.5–5.5 V and supports 3 MHz operation with automotive temperature rating (−40°C to +125°C), whereas the 25LC040T/SN operates from 2.5–5.5 V at up to 2 MHz and is rated only for industrial temperature (−40°C to +85°C). Voltage and timing mismatches may cause functional failure if substituted without validation.
What protection mechanisms prevent unintended writes to the 25C040T/SN memory array?
The 25C040T/SN employs three layered protections: (1) hardware WP pin - when low, disables all writes regardless of WREN state; (2) volatile write-enable latch - must be explicitly set via WREN instruction and resets after every write or power cycle; (3) nonvolatile block protection bits (BP0/BP1) - configured via WRSR to lock segments of the 512-byte array. These mechanisms collectively ensure robust immunity to noise, power glitches, and software errors in safety-critical applications using the 25C040T/SN.
25C040T/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
25C040T/SN FAQ
1.How can I place an order for 25C040T/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 25C040T/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 25C040T/SN reliable?
The price and inventory of 25C040T/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25C040T/SN is usually 5 days.
3.What payment methods are accepted for 25C040T/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25C040T/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25C040T/SN?
25C040T/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25C040T/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 25C040T/SN?
For technical support, including 25C040T/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25C040T/SN requirements.
6.How does Aetrix verify that 25C040T/SN is sourced from the original manufacturer or authorized distributors?
All 25C040T/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 25C040T/SN meets industry standards.
7.What is the process for return or replacement of 25C040T/SN?
All 25C040T/SN units undergo pre-shipment inspection (PSI). If there is an issue with 25C040T/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 25C040T/SN part is unused and in its original packaging.
Return procedure for 25C040T/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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