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Microchip Technology 25C040T-E/SN
- Part No.:
- 25C040T-E/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
25C040T-E/SN.pdf
- Description:
- IC EEPROM 4KBIT SPI 3MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,300
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Product details
Overview
25C040T-E/SN from Microchip Technology Inc. is a 4 Kbit (512 × 8) SPI-compatible serial EEPROM designed for nonvolatile data storage in automotive and industrial 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 delivers 1 million endurance cycles with >200 years data retention. It is used in engine control units for calibration parameter storage.
For engineers reviewing the 25C040T-E/SN datasheet, 25C040T-E/SN pinout, 25C040T-E/SN application, or 25C040T-E/SN equivalent, key selection criteria include its automotive-grade temperature range (–40°C to +125°C), hardware write protection via WP pin, HOLD functionality for interrupt-safe SPI communication, and TSSOP-8 packaging suitable for space-constrained PCB layouts.
Technical Context
The 25C040T-E/SN implements a standard SPI Mode 0,0 interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, WP, and HOLD control signals. Its internal architecture includes an 8-bit instruction register, STATUS register with WIP/WEL/BP bits, and page-based write logic that enforces 16-byte alignment within 4 memory blocks.
It uses on-chip high-voltage generation for EEPROM programming, supports sequential read with automatic address roll-over, and integrates power-on reset circuitry that clears the write enable latch and places SO in high-impedance state. Block protection is configurable via BP0/BP1 bits to lock 0%, 25%, 50%, or 100% of the array.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8 bits); sufficient for firmware configuration tables or sensor calibration coefficients in ECUs. |
| Supply voltage | 4.5–5.5 V; compatible with standard 5 V automotive power rails and tolerant of battery transients. |
| Max clock frequency | 3 MHz at VCC = 4.5–5.5 V; enables fast parameter reads during boot-up or diagnostics without CPU overhead. |
| Write cycle time | 5 ms maximum; deterministic erase-and-write timing simplifies timeout handling in safety-critical firmware. |
| Endurance & retention | 1 million write/erase cycles and >200 years data retention; meets ASIL-B functional safety data logging requirements. |
| Temperature range | –40°C to +125°C (Automotive E grade); qualified for under-hood deployment in engine management systems. |
| ESD protection | ≥4 kV HBM; provides robustness against assembly-line and field electrostatic discharge events. |
Pinout & Package
25C040T-E/SN is housed in an 8-pin TSSOP package (4.4 mm body width, 0.65 mm pitch), optimized for automated SMT assembly and thermal performance in high-density automotive modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 3) | Chip Select input | Active-low enable signal; deselecting forces SO into high-Z, enabling multi-device SPI bus sharing. |
| SO (Pin 4) | Serial data output | Drives MISO line; outputs data on falling edge of SCK; tri-states when CS high or HOLD low. |
| WP (Pin 5) | Hardware write-protect | Low = disables all writes to memory and STATUS register; critical for preventing corruption during power brownouts. |
| VSS (Pin 6) | Ground reference | Primary return path for all I/O and core logic; must be low-inductance connection in noisy automotive environments. |
| SI (Pin 7) | Serial data input | Accepts instructions, addresses, and data on rising edge of SCK; latched synchronously to avoid metastability. |
| SCK (Pin 8) | Serial clock input | Master-generated SPI clock; rising edge clocks SI, falling edge updates SO; timing validated to 3 MHz. |
| HOLD (Pin 1) | Communication suspend | Pauses ongoing SPI transfer without resetting state; allows host MCU to service higher-priority interrupts safely. |
| VCC (Pin 2) | Power supply | 4.5–5.5 V nominal; internal regulation ensures stable EEPROM programming voltage across rail variation. |
Key Features
| Feature | Design Value |
|---|---|
| Block write protection | Selectable 0%/25%/50%/100% array lock via STATUS register BP0/BP1 bits - prevents accidental overwrites of critical calibration zones. |
| Self-timed write cycles | No external timing components required; internal HV generator and state machine guarantee completion within 5 ms - simplifies firmware design. |
| HOLD pin functionality | Halts SPI communication mid-sequence while preserving internal address pointer - eliminates need for retransmission after interrupt servicing. |
| Power-on data protection | Write enable latch resets at power-up, and WP pin disables writes when low - prevents spurious writes during power ramp-up/down. |
| 16-byte page write | Enables burst programming of contiguous parameters (e.g., PID tuning sets) with single CS assertion - reduces SPI transaction overhead by 87.5% vs byte-write. |
Applications
| Engine Control Unit (ECU) | Advanced Driver Assistance System (ADAS) Camera Module |
|---|---|
|
Use Scenario: Storing real-time engine calibration maps, fault codes, and adaptive learning values that persist across ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile configuration storage interfaced directly to the ECU's SPI master; accessed during boot and runtime for map lookups. Use Value: Automotive-grade temperature rating and 1M-cycle endurance ensure reliable operation over 15+ year vehicle lifetimes under thermal cycling stress. |
Use Scenario: Retaining lens focus offsets, exposure compensation settings, and lens distortion coefficients across camera power cycles. IC Role / Device Role / Timing Role: SPI-connected parameter store for image signal processor (ISP); read at startup and updated only during factory calibration or OTA updates. Use Value: Hardware WP pin prevents corruption during unexpected power loss during firmware update - critical for functional safety compliance. |
| Industrial PLC I/O Module | Automotive Body Control Module (BCM) |
|
Use Scenario: Saving user-defined I/O mapping configurations, scaling factors, and alarm thresholds that survive maintenance power-downs. IC Role / Device Role / Timing Role: Serial EEPROM co-located with microcontroller on modular I/O board; accessed via dedicated SPI peripheral during initialization. Use Value: 5 ms max write time and page-write capability allow full configuration save in <100 ms - meets industrial watchdog timeout constraints. |
Use Scenario: Storing seat position memory, window auto-up/down limits, and lighting scene presets tied to driver profiles. IC Role / Device Role / Timing Role: Persistent parameter storage for BCM microcontroller; read at power-on and written only on user command or system event. Use Value: HOLD pin support enables safe interruption of EEPROM access during CAN message processing - avoids SPI bus contention in real-time networks. |
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/SN | Wider VCC range (1.8–5.5 V), lower 1 MHz max clock, industrial temp only (–40°C to +85°C). | Not qualified for under-hood automotive use; suitable for consumer or industrial control where voltage headroom is limited. | Choose only if 1.8 V operation or broader supply range is required and automotive temperature rating is unnecessary. |
| 25LC040T-I/SN | 2.5–5.5 V supply, 2 MHz max clock, industrial temp only; identical pinout and instruction set. | Lacks automotive qualification; lower max clock limits throughput in high-speed logging scenarios. | Select when 2.5 V compatibility is needed and ambient temperature stays below +85°C - e.g., cabin electronics or infotainment. |
Compared with 25C040T-E/SN, the 25AA040T-I/SN offers wider voltage flexibility but sacrifices automotive temperature rating and speed, while the 25LC040T-I/SN trades speed and qualification for 2.5 V compatibility - making 25C040T-E/SN the sole choice for safety-critical, high-temperature, 5 V automotive subsystems.
Availability
25C040T-E/SN is available at Aetrix Electronics and suitable for engine control units, ADAS camera modules, and automotive body control modules requiring stable component supply across extended product lifecycles.
Supply support for 25C040T-E/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 microcontrollers, analog devices, and memory solutions, serving automotive, industrial, and consumer markets with ISO/TS 16949-certified manufacturing.
The 25C040T-E/SN belongs to Microchip's legacy 25XX040 serial EEPROM family, engineered specifically for automotive and industrial applications demanding high reliability, hardware write protection, and extended temperature operation.
FAQ
What is the operating voltage range for the 25C040T-E/SN?
The 25C040T-E/SN operates strictly within 4.5 V to 5.5 V. This narrow range ensures robust performance in 5 V automotive systems and prevents unreliable operation outside specification - unlike broader-range variants such as the 25AA040T-I/SN. Operation below 4.5 V may result in incomplete writes or STATUS register corruption.
Does the 25C040T-E/SN support SPI Mode 0,0 exclusively?
Yes, the 25C040T-E/SN is compliant only with SPI Mode 0,0 (CPOL = 0, CPHA = 0). Data is sampled on the rising edge of SCK and shifted out on the falling edge. Attempting Mode 1,1 or other variants will cause communication failure, as confirmed by timing diagrams in DS21204E-page 4.
How does the HOLD pin function during an active write cycle in the 25C040T-E/SN?
The HOLD pin cannot suspend an internal write cycle once initiated; it only pauses serial instruction/data transfer. If HOLD is asserted during a write, the 25C040T-E/SN completes the ongoing 5 ms write before entering hold state. This behavior is explicitly documented in Section 2.6 and Figure 1-1 of DS21204E.
What is the purpose of the WP pin on the 25C040T-E/SN, and how does it interact with the write enable latch?
The WP pin on the 25C040T-E/SN is a hardware override: when low, it forces write inhibition regardless of WEL bit state. As stated in Table 3-3 and Section 2.3, WP low resets the write enable latch and blocks all writes to memory and STATUS register - providing fail-safe protection during power transitions.
Is the 25C040T-E/SN pin-compatible with other members of the 25XX040 family in TSSOP-8 packaging?
Yes, the 25C040T-E/SN shares identical TSSOP-8 pinout (CS/SO/WP/VSS/SI/SCK/HOLD/VCC on pins 3/4/5/6/7/8/1/2) with 25AA040T-I/SN and 25LC040T-I/SN per Table 2-1 in DS21204E. However, electrical differences (voltage range, speed, temp grade) require design validation before substitution.
25C040T-E/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:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
25C040T-E/SN FAQ
1.How can I place an order for 25C040T-E/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 25C040T-E/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-E/SN reliable?
The price and inventory of 25C040T-E/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-E/SN is usually 5 days.
3.What payment methods are accepted for 25C040T-E/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25C040T-E/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25C040T-E/SN?
25C040T-E/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25C040T-E/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-E/SN?
For technical support, including 25C040T-E/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25C040T-E/SN requirements.
6.How does Aetrix verify that 25C040T-E/SN is sourced from the original manufacturer or authorized distributors?
All 25C040T-E/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-E/SN meets industry standards.
7.What is the process for return or replacement of 25C040T-E/SN?
All 25C040T-E/SN units undergo pre-shipment inspection (PSI). If there is an issue with 25C040T-E/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-E/SN part is unused and in its original packaging.
Return procedure for 25C040T-E/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25C040T-E/SN Tags
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AT24C02C-XHM-T
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