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Microchip Technology 25LC040AT-E/OT
- Part No.:
- 25LC040AT-E/OT
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- SOT-23-6
- Datasheet:
-
25LC040AT-E/OT.pdf
- Description:
- IC EEPROM 4KBIT SPI SOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:5,779
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Product details
Overview
25LC040AT-E/OT from Microchip Technology Inc. is a 4 Kbit SPI Serial EEPROM with 512 × 8-bit organization, 16-byte page write capability, and automotive-grade temperature support (−40°C to +125°C). It operates from 2.5V to 5.5V, supports up to 10 MHz clock frequency, and features hardware write protection via WP pin and HOLD functionality for interrupt-safe bus suspension - used in engine control units and automotive sensor calibration storage.
For engineers reviewing the 25LC040AT-E/OT datasheet, 25LC040AT-E/OT pinout, 25LC040AT-E/OT application, or 25LC040AT-E/OT equivalent, key selection criteria include its SOT-23-6 package, automotive qualification, 1 M endurance cycles, 200-year data retention, and SPI interface timing compatibility with PIC® and ARM-based microcontrollers.
Technical Context
The 25LC040AT-E/OT implements a standard SPI Mode 0,0/Master-Slave interface with separate SI/SO lines and CS-controlled device selection. Its internal architecture includes an 8-bit instruction register, page latches, and high-voltage generator for EEPROM programming, enabling byte- and page-write operations with automatic address incrementing during sequential reads.
It integrates dual write-protection mechanisms: a nonvolatile STATUS register (BP0/BP1) for configurable block protection (none/1/4/1/2/all), and a dedicated WP pin that disables all writes when asserted low - both active during power-on reset and after WREN/WRDI execution.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit array), sufficient for firmware patch storage or configuration parameters in space-constrained automotive modules. |
| Interface | SPI-compatible serial bus (Mode 0,0), requiring only CS, SCK, SI, SO, WP, HOLD, VCC, VSS - minimal MCU GPIO usage. |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5V, enabling fast read/write transfers (e.g., <5 ms page write) without MCU clock scaling. |
| Write Endurance | 1,000,000 erase/write cycles, supporting long-term field updates in telematics or ADAS calibration data logging. |
| Data Retention | >200 years at +25°C, ensuring reliable storage of safety-critical calibration constants over vehicle lifetime. |
| Operating Voltage | 2.5V–5.5V supply range, compatible with 3.3V and 5V automotive subsystems without level-shifting. |
| Temperature Range | −40°C to +125°C (Automotive E grade), qualified for under-hood and transmission control unit environments. |
Pinout & Package
25LC040AT-E/OT uses a 6-pin SOT-23 package (package code OT), with footprint dimensions of 2.9 mm × 1.6 mm × 1.1 mm (max height), optimized for high-density PCB layouts in automotive ECUs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSS | Ground reference | Return path for all internal logic and EEPROM core; must be low-impedance to ensure stable read/write margins. |
| VDD | Supply voltage input | Power source (2.5–5.5V); decoupling capacitor required within 10 mm to suppress switching noise during write cycles. |
| CS | Chip Select input | Active-low enable signal; rising edge initiates internal write cycle; high state places SO in high-Z for multi-device SPI bus sharing. |
| SO | Serial Data Output | Tri-state output delivering memory contents on falling SCK edge; high-Z when CS = high or HOLD = low. |
| SCK | Serial Clock Input | Master-generated clock synchronizing all data transfers; rising edge latches SI, falling edge updates SO. |
| SI | Serial Data Input | Accepts instructions (READ/WRITE/WREN/RDSR), addresses, and data on rising SCK edge; sampled only when CS = low. |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Mode | Up to 16 bytes written per command within same physical page (00h–0Fh, 10h–1Fh, etc.), reducing SPI transaction overhead vs. byte writes. |
| HOLD Functionality | HOLD pin suspends ongoing SPI transfer without resetting internal state, allowing MCU to service higher-priority interrupts and resume seamlessly. |
| Hardware Write Protection | WP pin disables all writes (array and STATUS register) when pulled low - independent of WEL latch state, providing fail-safe protection. |
| Block Protection Configuration | BP0/BP1 bits in STATUS register allow nonvolatile selection of 0%, 25%, 50%, or 100% array write protection - configurable per system security policy. |
| Power-On Write Disable | Write enable latch resets at power-up, preventing accidental writes during power-rail stabilization or brown-out conditions. |
Applications
| Engine Control Unit (ECU) | Advanced Driver Assistance Systems (ADAS) |
|---|---|
Use Scenario: Storing adaptive fuel trim values and misfire counters updated during vehicle operation. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced directly to PIC18F66K80 MCU via SPI, accessed during idle periods. Use Value: Enables closed-loop engine optimization across 1M+ drive cycles while maintaining >200-year data integrity at 125°C ambient. | Use Scenario: Holding camera calibration offsets and radar beam alignment coefficients subject to periodic field updates. IC Role / Device Role / Timing Role: SPI EEPROM storing safety-critical sensor metadata; accessed during boot and post-diagnostic routines. Use Value: Automotive-grade temperature rating and 1M endurance ensure reliability in vibration-prone mounting locations near front bumper. |
| Body Control Module (BCM) | Electric Power Steering (EPS) |
Use Scenario: Retaining window position limits, seat memory profiles, and lighting presets across ignition cycles. IC Role / Device Role / Timing Role: Low-power SPI EEPROM operating from 3.3V rail; accessed via GPIO-bit-banged SPI during sleep-mode wake events. Use Value: 5 µA standby current extends battery life during vehicle dormancy; WP pin prevents corruption during CAN bus surge events. | Use Scenario: Storing torque sensor zero-point compensation and motor phase advance tables updated during dealer recalibration. IC Role / Device Role / Timing Role: Fail-operational memory element connected to Infineon AURIX™ TC3xx via hardware SPI peripheral. Use Value: HOLD pin allows interruption of calibration writes during emergency steering maneuvers without data loss or bus contention. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA040AT-I/OT | Industrial temp range (−40°C to +85°C); 1.8–5.5V supply; identical pinout and SPI protocol. | Not qualified for under-hood automotive use; suitable for cabin electronics or industrial controllers. | Select only if ambient temperature remains ≤85°C and lower VCC min (1.8V) is needed. |
| AT25040B-SSHL-T | Same 4 Kbit size, SPI interface, and SOT-23-6 package; 1.8–5.5V; −40°C to +85°C; 1M endurance. | Lacks HOLD pin and hardware WP; relies solely on STATUS register BP bits for protection. | Choose when HOLD functionality is unnecessary and cost sensitivity outweighs automotive qualification. |
Compared with 25AA040AT-I/OT, the 25LC040AT-E/OT adds automotive temperature range and higher VCC minimum (2.5V), while AT25040B-SSHL-T omits critical fault-tolerant features (HOLD, WP pin), limiting suitability for safety-relevant automotive subsystems.
Availability
25LC040AT-E/OT is available at Aetrix Electronics and suitable for automotive control units, ADAS sensor calibration systems, and body electronics requiring stable component supply with full AEC-Q200 alignment and traceable sourcing.
Supply support for 25LC040AT-E/OT 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, with global manufacturing and quality certifications including IATF 16949.
The 25LC040A product line delivers automotive-qualified serial EEPROMs designed specifically for mission-critical data storage in harsh-temperature environments, emphasizing reliability, write-protection robustness, and SPI interoperability with Microchip's PIC® and dsPIC® families.
FAQ
What is the maximum clock frequency supported by the 25LC040AT-E/OT?
The 25LC040AT-E/OT supports up to 10 MHz clock frequency when VCC is 4.5V–5.5V, 5 MHz at 2.5V–4.5V, and 3 MHz at 1.8V–2.5V (though 25LC040AT-E/OT's minimum VCC is 2.5V). This enables high-speed configuration reads in real-time automotive control loops without bottlenecking the SPI bus.
Does the 25LC040AT-E/OT include hardware write protection independent of software control?
Yes, the 25LC040AT-E/OT includes a dedicated WP pin (Pin 3 in SOT-23) that disables all write operations - including STATUS register updates - when held low. This hardware-level protection operates regardless of the WEL latch state and remains active through power cycles, providing fail-safe defense against electrical transients.
How does the HOLD function operate in the 25LC040AT-E/OT during an active SPI transfer?
The HOLD pin (Pin 1 in SOT-23) suspends ongoing SPI communication when pulled low while SCK is low. During HOLD, SI/SO/SCK inputs are ignored, SO enters high-impedance, and internal state is preserved. Resuming requires bringing HOLD high while SCK is low - enabling deterministic MCU interrupt handling without reinitializing the transaction.
What package type and dimensions does the 25LC040AT-E/OT use?
The 25LC040AT-E/OT uses a 6-pin SOT-23 package (Microchip package code OT), measuring 2.9 mm × 1.6 mm × 1.1 mm (max height), with gull-wing leads and RoHS-compliant matte tin plating. Its compact footprint supports high-density placement in space-constrained automotive modules like EPS control boards.
Can the 25LC040AT-E/OT be used in systems requiring AEC-Q200 compliance?
While the 25LC040AT-E/OT is specified for the automotive temperature range (−40°C to +125°C) and manufactured using automotive-aligned processes, formal AEC-Q200 qualification status must be verified per lot via Microchip's official documentation or authorized distributor reports - Aetrix Electronics provides traceable lot data upon request.
25LC040AT-E/OT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- SOT-23-6
- 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:
- 10 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-6
25LC040AT-E/OT FAQ
1.How can I place an order for 25LC040AT-E/OT through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC040AT-E/OT 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 25LC040AT-E/OT reliable?
The price and inventory of 25LC040AT-E/OT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC040AT-E/OT is usually 5 days.
3.What payment methods are accepted for 25LC040AT-E/OT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC040AT-E/OT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC040AT-E/OT?
25LC040AT-E/OT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC040AT-E/OT 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 25LC040AT-E/OT?
For technical support, including 25LC040AT-E/OT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC040AT-E/OT requirements.
6.How does Aetrix verify that 25LC040AT-E/OT is sourced from the original manufacturer or authorized distributors?
All 25LC040AT-E/OT 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 25LC040AT-E/OT meets industry standards.
7.What is the process for return or replacement of 25LC040AT-E/OT?
All 25LC040AT-E/OT units undergo pre-shipment inspection (PSI). If there is an issue with 25LC040AT-E/OT, 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 25LC040AT-E/OT part is unused and in its original packaging.
Return procedure for 25LC040AT-E/OT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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