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Microchip Technology 25LC040AXT-I/ST
- Part No.:
- 25LC040AXT-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25LC040AXT-I/ST.pdf
- Description:
- IC EEPROM 4KBIT SPI 10MHZ 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,165
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Product details
Overview
25LC040AXT-I/ST from Microchip Technology Inc. is a 4 Kbit SPI Serial EEPROM with 512 × 8-bit organization, 16-byte page write capability, and industrial temperature range (–40°C to +85°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 block-level protection (none/¼/½/all array). It is used for nonvolatile parameter storage in microcontroller-based embedded systems requiring reliable, low-power data retention.
For engineers reviewing the 25LC040AXT-I/ST datasheet, 25LC040AXT-I/ST pinout, 25LC040AXT-I/ST application, or 25LC040AXT-I/ST equivalent, this page provides verified technical context, real-world use cases, pin-level design meaning, and validated alternative options - all aligned to the DS21827H specification and ST-package implementation.
Technical Context
The 25LC040AXT-I/ST implements an SPI-compatible serial interface with separate SI (data-in), SO (data-out), SCK (clock), CS (chip select), WP (write-protect), and HOLD (communication pause) signals. Its internal architecture includes a 512-byte EEPROM array, page latches, status register (WIP/WEL/BP0/BP1), and high-voltage generator for erase/write cycles.
It supports byte and page write modes (max 16 bytes/page), sequential read with automatic address increment, and self-timed internal write cycles ≤5 ms. Write enable latch control, power-on reset behavior, and hardware WP pin interaction are defined per Table 2-4 and Section 2.7 - ensuring deterministic write-protection enforcement across voltage and temperature ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit), sufficient for firmware configuration, calibration data, or device ID storage in space-constrained designs. |
| Interface | SPI-compatible 4-wire serial bus (CS, SCK, SI, SO) with HOLD and WP pins - requires no additional level-shifting for 2.5–5.5V MCU hosts. |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5V - enables fast parameter reads/writes without CPU polling overhead in real-time systems. |
| Write Cycle Time | ≤5 ms per byte or page - deterministic timing allows precise scheduling of nonvolatile updates without blocking main application flow. |
| Data Retention | >200 years at +25°C - ensures long-term integrity of stored settings across product lifecycle without refresh logic. |
| Endurance | 1,000,000 erase/write cycles - supports frequent logging or runtime parameter adjustment in industrial controllers. |
| Operating Voltage | 2.5V to 5.5V - compatible with both 3.3V and 5V logic domains, simplifying integration into mixed-supply systems. |
| Temperature Range | Industrial: –40°C to +85°C - qualified for deployment in automotive body electronics, industrial sensors, and HVAC controls. |
Pinout & Package
25LC040AXT-I/ST is packaged in an 8-lead TSSOP (ST package), 3.0 mm × 4.4 mm body, 0.65 mm pitch, with pin 1 marked by laser dot. Pin functions match standard SPI EEPROM topology and are electrically validated per DS21827H Table 3-1 and Figure 3-1 (TSSOP layout).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 CS | Chip Select Input | Active-low enable: drives device into active mode; rising edge initiates internal write cycle after valid command sequence. |
| 2 SO | Serial Data Output | Tri-state open-drain output: delivers read data MSb-first on falling SCK edge; high-impedance when CS high or HOLD low. |
| 3 WP | Write-Protect Pin | Hardware lock: pulls low to disable all writes (array + STATUS register); overrides WEL state per Table 2-4. |
| 4 VSS | Ground Reference | Primary return path for all I/O and core circuitry; must be low-impedance and decoupled near VCC pin. |
| 5 SI | Serial Data Input | CMOS input: accepts instruction, address, and data bits MSb-first on rising SCK edge; sampled only when CS low. |
| 6 SCK | Serial Clock Input | Synchronous timing reference: defines data setup/hold windows (e.g., Tsu = 10 ns min at VCC ≥ 4.5V). |
| 7 HOLD | Hold Input | Pauses ongoing SPI transfer: tri-states SO/SI/SCK while preserving internal state; resumes from exact point on HOLD high. |
| 8 VCC | Supply Voltage | Power rail: 2.5–5.5V operation; supplies internal charge pump for write/erase; requires 0.1 µF ceramic bypass capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Mode (16 bytes) | Reduces write latency vs. byte-by-byte: enables efficient bulk parameter updates (e.g., full sensor calibration set) within one ≤5 ms cycle. |
| Block Write Protection | Configurable via STATUS register (BP0/BP1): allows selective locking of upper ¼, ½, or entire array - prevents accidental overwrite of critical firmware data. |
| Power-On Write Disable | WEL latch resets at power-up: eliminates risk of spurious writes during supply ramp; requires explicit WREN before any write. |
| HOLD Functionality | Enables interrupt-safe SPI communication: host MCU can service higher-priority tasks mid-transfer without reinitializing sequence. |
| Low Standby Current (5 µA) | Minimizes battery drain in always-on applications (e.g., smart meters, IoT edge nodes) while retaining full memory content. |
| ESD Robustness (4 kV HBM) | Withstands handling and board-level ESD events without latch-up or data corruption - reduces need for external protection components. |
Applications
| Industrial Sensor Calibration Storage | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: Storing factory-calibrated offset/gain coefficients for temperature, pressure, and humidity sensors in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile parameter repository accessed during system boot and periodic self-test; SPI interface synchronized to MCU's peripheral clock. Use Value: Enables field-replaceable sensor modules without firmware reflash; 1M endurance supports recalibration over 10+ years of maintenance cycles. |
Use Scenario: Holding seat position memory, mirror angle presets, and lighting configuration profiles in 12V automotive BCMs. IC Role / Device Role / Timing Role: SPI EEPROM interfaced to 8-bit or 32-bit automotive MCU; accessed during ignition-on initialization and user-adjustment events. Use Value: Industrial temp rating (–40°C to +85°C) ensures reliability under hood ambient extremes; WP pin prevents corruption during load dump transients. |
| Medical Infusion Pump Settings | Smart Energy Meter Firmware Parameters |
|
Use Scenario: Retaining drug library definitions, dose limits, and alarm thresholds in Class II medical devices requiring FDA-compliant data integrity. IC Role / Device Role / Timing Role: Secure configuration store with dual protection: hardware WP pin + BP bits to lock safety-critical registers. Use Value: >200-year data retention meets long-service-life requirements; 4 kV ESD rating supports safe handling during assembly and service. |
Use Scenario: Storing tariff schedules, metering constants, and cryptographic keys in ANSI C12.22-compliant utility meters deployed in outdoor enclosures. IC Role / Device Role / Timing Role: Low-power SPI EEPROM accessed infrequently but with guaranteed write completion; HOLD pin used during RF burst transmission. Use Value: 5 µA standby current extends battery backup life beyond 10 years; 2.5V min VCC supports brownout operation during grid instability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SPI EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA040AT-I/ST | Wider VCC range (1.8–5.5V); identical pinout, timing, and memory map; same ST package. | Supports 1.8V logic domains (e.g., ultra-low-power MCUs); not rated for automotive temp range. | Select when interfacing with 1.8V or 2.5V-only systems; verify VCC stability margins if operating below 2.5V. |
| AT25040B-SSHL-T | Same 4 Kbit size, SPI interface, and 8-pin SOIC/TSSOP packages; max clock 20 MHz; 1M endurance; 100-year retention. | Higher speed and different status register bit mapping; lacks HOLD pin; RoHS-compliant but not AEC-Q200 qualified. | Choose for cost-sensitive consumer applications where HOLD functionality is unused and 20 MHz throughput is beneficial. |
Compared with 25LC040AXT-I/ST, the 25AA040AT-I/ST extends voltage flexibility downward but omits automotive qualification, while the AT25040B-SSHL-T trades HOLD support and industrial temp assurance for higher clock rate - making each suitable only for specific subsystem voltage, timing, and reliability constraints.
Availability
25LC040AXT-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control modules, medical infusion pump configuration, and smart energy meter firmware parameters requiring stable component supply across multi-year production cycles.
Supply support for 25LC040AXT-I/ST 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 company specializing in microcontrollers, analog devices, and memory solutions, with global manufacturing and quality certifications including ISO 9001 and IATF 16949.
The 25LC040A family was designed for robust, low-power nonvolatile data storage in resource-constrained embedded systems - emphasizing SPI simplicity, write-protection integrity, and long-term reliability in industrial and automotive environments.
FAQ
What is the maximum clock frequency supported by the 25LC040AXT-I/ST?
The 25LC040AXT-I/ST supports up to 10 MHz clock frequency when VCC is 4.5V to 5.5V, 5 MHz at 2.5V to <4.5V, and 3 MHz at 1.8V to <2.5V - though the 25LC040AXT-I/ST is specified only for 2.5V–5.5V operation, so 10 MHz is its maximum usable rate. This enables fast parameter access in time-critical applications without compromising timing margin.
Does the 25LC040AXT-I/ST include hardware write protection?
Yes, the 25LC040AXT-I/ST includes dedicated hardware write protection via the WP pin (Pin 3). When pulled low, it disables all writes to memory and STATUS register regardless of WEL state - a critical safeguard against accidental corruption during power transitions or noise events. This feature is explicitly defined in Table 2-4 and Section 3.3 of the DS21827H datasheet.
What package type is used for the 25LC040AXT-I/ST?
The 25LC040AXT-I/ST uses an 8-lead TSSOP package (ST suffix), measuring 3.0 mm × 4.4 mm with 0.65 mm lead pitch and laser-marked pin 1 identification. This compact, surface-mount package is optimized for automated assembly and thermal performance in dense PCB layouts, matching the mechanical drawings in DS21827H pages 30–31.
How does the HOLD pin function on the 25LC040AXT-I/ST?
The HOLD pin (Pin 7) suspends ongoing SPI communication without resetting the internal state: pulling it low places SO, SI, and SCK in high-impedance while preserving address and instruction context. Resuming requires HOLD high while SCK is low. This allows the host MCU to service interrupts mid-transfer - a key capability confirmed in Section 3.6 and Figure 1-1 of DS21827H.
What is the endurance and data retention specification for the 25LC040AXT-I/ST?
The 25LC040AXT-I/ST guarantees 1,000,000 erase/write cycles and >200 years of data retention at +25°C, as stated in Table 1-3 (Param. 21) and Section 1.0 of DS21827H. These values are characterized and ensured per Microchip's reliability testing protocols - enabling long-life deployments in infrastructure and medical equipment where field replacement is costly or impractical.
25LC040AXT-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm 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:
- 10 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
25LC040AXT-I/ST FAQ
1.How can I place an order for 25LC040AXT-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC040AXT-I/ST 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 25LC040AXT-I/ST reliable?
The price and inventory of 25LC040AXT-I/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC040AXT-I/ST is usually 5 days.
3.What payment methods are accepted for 25LC040AXT-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC040AXT-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC040AXT-I/ST?
25LC040AXT-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC040AXT-I/ST 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 25LC040AXT-I/ST?
For technical support, including 25LC040AXT-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC040AXT-I/ST requirements.
6.How does Aetrix verify that 25LC040AXT-I/ST is sourced from the original manufacturer or authorized distributors?
All 25LC040AXT-I/ST 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 25LC040AXT-I/ST meets industry standards.
7.What is the process for return or replacement of 25LC040AXT-I/ST?
All 25LC040AXT-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 25LC040AXT-I/ST, 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 25LC040AXT-I/ST part is unused and in its original packaging.
Return procedure for 25LC040AXT-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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