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Microchip Technology 25LC040AX-E/ST
- Part No.:
- 25LC040AX-E/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25LC040AX-E/ST.pdf
- Description:
- IC EEPROM 4KBIT SPI 10MHZ 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,047
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Product details
Overview
25LC040AX-E/ST from Microchip Technology Inc. is a 4 Kbit (512 × 8) SPI Serial EEPROM with 16-byte page write capability, 10 MHz max clock frequency, and industrial-automotive temperature support (−40°C to +125°C). It features hardware write protection (WP pin), HOLD functionality for interrupt-safe serial pauses, and block-level array protection (none/¼/½/all). Used in automotive body control modules for storing calibration data and fault logs.
For engineers reviewing the 25LC040AX-E/ST datasheet, 25LC040AX-E/ST pinout, 25LC040AX-E/ST application, or 25LC040AX-E/ST equivalent, key selection criteria include VCC range (2.5–5.5 V), page write timing (≤5 ms), endurance (1M cycles), data retention (>200 years), and TSSOP-8 package compatibility with SPI-based microcontroller interfaces.
Technical Context
The 25LC040AX-E/ST implements a standard SPI Mode 0,0 or 1,1 interface with separate SI/SO lines, CS-controlled selection, and SCK-synchronized data transfer. Its internal architecture includes an 8-bit instruction register, status register (WIP/WEL/BP0/BP1), and page latches enabling up to 16-byte writes within fixed 16-byte physical boundaries.
Hardware protections include active-low WP pin disabling all writes regardless of WEL state, power-on reset of the write enable latch, and automatic WEL reset after each successful WRITE/WRSR operation. The HOLD pin suspends ongoing transfers while maintaining internal state, allowing host MCU to service higher-priority interrupts without reinitializing the sequence.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8 bits); supports 9-bit addressing for full array access |
| Interface | SPI-compatible serial bus (Mode 0,0 and 1,1); requires CS, SCK, SI, SO, WP, HOLD |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5 V; enables fast configuration reads in boot-time-critical systems |
| Write Cycle Time | ≤5 ms per byte or page; deterministic timing simplifies firmware polling logic |
| Endurance & Retention | 1,000,000 erase/write cycles; >200 years data retention at 25°C - suitable for lifetime automotive storage |
| VCC Range | 2.5 V to 5.5 V; compatible with 3.3 V and 5 V MCU I/O domains without level shifting |
| Temperature Range | −40°C to +125°C (Automotive grade E); validated for under-hood and powertrain applications |
Pinout & Package
25LC040AX-E/ST is packaged in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch and exposed pad option (not connected by default). Pin 1 is marked by laser indentation; package conforms to JEDEC MO-153.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select Input | Active-low enable; must be low for all operations; rising edge initiates internal write cycle |
| SO (Pin 2) | Serial Data Output | Tri-state output; data shifted out MSb-first on falling SCK edge during READ |
| WP (Pin 3) | Write-Protect Input | Hardware lock: low disables all writes to memory and STATUS register regardless of WEL state |
| VSS (Pin 4) | Ground Reference | Primary return path for all digital and internal charge-pump circuits |
| SI (Pin 5) | Serial Data Input | Instruction/address/data input latched on rising SCK edge; MSb-first protocol |
| SCK (Pin 6) | Serial Clock Input | Master-generated clock; defines timing for SI sampling and SO updates |
| HOLD (Pin 7) | Hold Input | Pauses active SPI transaction; SO goes high-Z; resumes from exact point on HOLD high |
| VCC (Pin 8) | Supply Voltage | 2.5–5.5 V operating range; powers logic, EEPROM array, and internal HV generator |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Mode | Up to 16 bytes written atomically within one 16-byte physical page - reduces firmware overhead vs. byte-by-byte writes |
| Block Write Protection | Configurable via STATUS register (BP1/BP0): protect none, upper 1/4 (180h–1FFh), upper 1/2 (100h–1FFh), or entire array (000h–1FFh) |
| Power-On Write Protection | Write enable latch resets at power-up; prevents spurious writes during supply ramp-up or brownout |
| HOLD Functionality | Enables non-disruptive pause/resume of SPI sequences - critical for real-time MCUs handling CAN or PWM interrupts |
| ESD Robustness | ≥4000 V HBM - ensures reliability in automotive assembly and field environments with high static potential |
Applications
| Automotive Body Control Unit (BCU) | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing seat position presets, mirror calibration offsets, and door lock configuration across vehicle life cycles. IC Role / Device Role / Timing Role: Nonvolatile parameter storage accessed during startup and runtime via SPI from 32-bit automotive MCU. Use Value: 1M endurance and >200-year retention ensure zero field failures over 15+ year vehicle service life. |
Use Scenario: Holding I/O mapping tables, PID tuning parameters, and firmware update flags in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: SPI-configurable persistent memory interfaced to ARM Cortex-M7 with HOLD support for deterministic scan-cycle timing. Use Value: Hardware WP pin prevents accidental overwrite during hot-plug I/O module replacement or firmware upload. |
| Medical Infusion Pump Calibration | Smart Energy Meter Firmware Bootloader |
Use Scenario: Securing drug delivery rate coefficients, dose history logs, and sensor calibration constants compliant with IEC 62304. IC Role / Device Role / Timing Role: Safety-critical NVM accessed only during maintenance mode; BP1/BP0 bits lock configuration post-calibration. Use Value: Block protection prevents unauthorized modification of dosing algorithms - satisfies Class C software safety requirements. |
Use Scenario: Storing secure bootloader keys, meter serial number, tariff schedules, and tamper-event counters in ANSI C12.22-compliant meters. IC Role / Device Role / Timing Role: SPI EEPROM holding immutable root-of-trust data; read at power-on before executing signed application image. Use Value: 2.5–5.5 V VCC range matches wide-input DC-DC outputs; 125°C rating supports transformer-coupled meter enclosures. |
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/ST | Wider VCC range (1.8–5.5 V); rated for Industrial (−40°C to +85°C) only; same pinout and instruction set | Not qualified for automotive ambient temperatures; unsuitable for under-hood placement | Select when system operates below 2.5 V or requires extended low-VCC margin, but automotive qualification is not needed |
| AT25040B-MAHL-T | Same 4 Kbit size and SPI interface; 20 MHz max clock; 1.8–5.5 V VCC; different STATUS register layout and WP behavior | Requires firmware adaptation for status bit interpretation and write-protection logic; no HOLD pin | Choose for higher-speed read throughput where HOLD functionality is unused and design can accommodate Atmel-specific register mapping |
Compared with 25LC040AX-E/ST, the 25AA040AT-I/ST offers broader voltage flexibility but lacks automotive temperature certification, while the AT25040B-MAHL-T delivers faster clocking and wider VCC but removes HOLD support and introduces register-level incompatibility requiring firmware changes.
Availability
25LC040AX-E/ST is available at Aetrix Electronics and suitable for automotive electronics, industrial control systems, and medical device manufacturing requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for 25LC040AX-E/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 leading provider of microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global manufacturing and support infrastructure.
The 25LC040A family is designed specifically for automotive-grade serial EEPROM applications demanding high reliability, extended temperature operation, and robust hardware write protection in safety-critical systems.
FAQ
What is the maximum clock frequency supported by the 25LC040AX-E/ST?
The 25LC040AX-E/ST supports up to 10 MHz clock frequency when VCC is 4.5 V to 5.5 V. At 2.5 V ≤ VCC < 4.5 V, the maximum is 5 MHz, and at 1.8 V ≤ VCC < 2.5 V, it drops to 3 MHz. These limits are defined in Table 1-2 of the DS21827H datasheet and ensure reliable setup/hold timing across voltage and temperature ranges. The 25LC040AX-E/ST does not operate above these frequencies.
Does the 25LC040AX-E/ST have a HOLD pin, and how is it used?
Yes, the 25LC040AX-E/ST includes an active-low HOLD pin (Pin 7) that suspends ongoing SPI communication without resetting the internal state. When asserted low while SCK is low, SI/SO/SCK inputs are ignored and SO enters high-impedance. Resuming requires bringing HOLD high while SCK remains low. This allows the host MCU to service time-critical interrupts and resume exactly where the transaction paused - a feature confirmed in Section 2.6 and Figure 1-1 of the 25LC040AX-E/ST datasheet.
How does write protection work on the 25LC040AX-E/ST?
25LC040AX-E/ST implements dual-layer write protection: hardware via the WP pin (low = all writes disabled), and software via BP0/BP1 bits in the STATUS register (configurable 0–100% array lock). The WP pin overrides the WEL bit - even if WEL=1, WP=0 blocks all writes. Table 2-4 and Section 2.4 confirm this hierarchy. This ensures failsafe protection against firmware errors or voltage glitches during critical operations.
What package type is used for the 25LC040AX-E/ST?
The 25LC040AX-E/ST uses an 8-lead TSSOP (Thin Shrink Small Outline Package) with standard JEDEC MO-153 dimensions, 0.65 mm lead pitch, and laser-marked Pin 1 identification. Package marking code "X/ST" in the datasheet's Package Types table explicitly maps "ST" to TSSOP. This surface-mount package supports automated assembly and provides thermal performance suitable for automotive under-hood environments.
Is the 25LC040AX-E/ST RoHS compliant and Pb-free?
Yes, the 25LC040AX-E/ST is Pb-free and RoHS compliant, as stated in the Features section on page 1 of DS21827H. The package marking includes the Pb-free JEDEC designator "3e", and the "Pb-Free and RoHS Compliant" bullet confirms regulatory conformance. This applies to all package variants including the ST (TSSOP) variant, meeting EU Directive 2011/65/EU requirements for hazardous substance restrictions.
25LC040AX-E/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not 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:
- 8-TSSOP
25LC040AX-E/ST FAQ
1.How can I place an order for 25LC040AX-E/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC040AX-E/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 25LC040AX-E/ST reliable?
The price and inventory of 25LC040AX-E/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC040AX-E/ST is usually 5 days.
3.What payment methods are accepted for 25LC040AX-E/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC040AX-E/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC040AX-E/ST?
25LC040AX-E/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC040AX-E/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 25LC040AX-E/ST?
For technical support, including 25LC040AX-E/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC040AX-E/ST requirements.
6.How does Aetrix verify that 25LC040AX-E/ST is sourced from the original manufacturer or authorized distributors?
All 25LC040AX-E/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 25LC040AX-E/ST meets industry standards.
7.What is the process for return or replacement of 25LC040AX-E/ST?
All 25LC040AX-E/ST units undergo pre-shipment inspection (PSI). If there is an issue with 25LC040AX-E/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 25LC040AX-E/ST part is unused and in its original packaging.
Return procedure for 25LC040AX-E/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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