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Microchip Technology 25LC040XT-I/ST
- Part No.:
- 25LC040XT-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25LC040XT-I/ST.pdf
- Description:
- IC EEPROM 4KBIT SPI 2MHZ 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,434
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Product details
Overview
25LC040XT-I/ST from Microchip Technology Inc. is a 4 Kbit (512 × 8) SPI-compatible serial EEPROM with 2.5–5.5 V supply range, 2 MHz max clock frequency, and industrial temperature range (−40°C to +85°C). It features 16-byte page write capability, hardware write protection via WP pin, and HOLD functionality for interrupt-safe bus suspension. Used in embedded systems for firmware storage, calibration data retention, and configuration parameter backup.
For engineers reviewing the 25LC040XT-I/ST datasheet, 25LC040XT-I/ST pinout, 25LC040XT-I/ST application, or 25LC040XT-I/ST equivalent, key selection considerations include its TSSOP-8 package with alternate pinout (ST), 5 ms max internal write cycle time, 1 million endurance cycles, and block-level write protection covering 0%, 25%, 50%, or 100% of memory array.
Technical Context
The 25LC040XT-I/ST implements a standard SPI Mode 0,0 or Mode 1,1 interface with separate SI (data in) and SO (data out) lines, CS-controlled device selection, and SCK-synchronized transfers. Its instruction set includes READ, WRITE, WREN, WRDI, RDSR, and WRSR - enabling byte/page writes, status monitoring, and nonvolatile block protection configuration.
It integrates power-on reset logic that clears the write enable latch, built-in ESD protection (>4 kV), and low-power operation: 500 μA typical read current, 3 mA typical write current, and 500 nA standby current. The HOLD pin suspends ongoing serial sequences without resetting internal address pointers, allowing deterministic resumption after host interrupt servicing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit organization), sufficient for small firmware patches or sensor calibration tables |
| Interface | SPI-compatible serial bus (Mode 0,0 / Mode 1,1), requiring only CS, SCK, SI, SO, WP, and HOLD signals |
| Max clock frequency | 2 MHz at VCC = 2.5–4.5 V, enabling ~200 kB/s burst read throughput in optimal conditions |
| Write cycle time | 5 ms maximum internal write time per page or byte, dictating minimum delay before status polling or next command |
| Endurance & retention | 1 million write/erase cycles and >200 years data retention, validated for long-life industrial deployments |
| Supply voltage | 2.5–5.5 V operating range, compatible with 3.3 V and 5 V logic domains without level shifting |
| Temperature range | Industrial grade: −40°C to +85°C, qualified for use in control panels, metering, and factory automation |
Pinout & Package
25LC040XT-I/ST uses an 8-pin Thin Shrink Small Outline Package (TSSOP) with alternate pinout (ST designation), measuring 4.4 mm × 3.0 mm × 1.0 mm. This ST variant swaps pin positions compared to standard TSSOP: HOLD is on pin 1, VCC on pin 2, CS on pin 3, SO on pin 4, WP on pin 5, VSS on pin 6, SI on pin 7, and SCK on pin 8.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: HOLD | Serial communication suspend control | Tri-states SO and ignores SI/SCK transitions when low; must be held high during normal operation |
| 2: VCC | Positive supply voltage | 2.5–5.5 V input; powers internal logic, EEPROM array, and HV generator for write operations |
| 3: CS | Chip select input | Active-low enable; initiates instruction decode on falling edge and forces SO into high-Z when high |
| 4: SO | Serial data output | Outputs MSB-first data on falling SCK edge; enters high-impedance state when CS or HOLD is high |
| 5: WP | Hardware write-protect input | Disables all nonvolatile writes (array and STATUS register) when pulled low, independent of WEL state |
| 6: VSS | Ground reference | Return path for all internal currents; must be connected to system ground with low-impedance trace |
| 7: SI | Serial data input | Accepts instructions, addresses, and data on rising SCK edge; latched synchronously to clock |
| 8: SCK | Serial clock input | Master-generated clock; defines timing for SI sampling (rising edge) and SO update (falling edge) |
Key Features
| Feature | Design Value |
|---|---|
| 16-byte page write buffer | Enables efficient multi-byte programming within same 16-byte boundary, reducing total write cycles vs. byte-by-byte |
| Block write protection (BP0/BP1) | Configurable via WRSR to protect 0%, 25%, 50%, or 100% of memory - prevents accidental overwrite of critical firmware sections |
| HOLD pin with deterministic resume | Pauses active SPI sequence mid-transfer; resumes from exact bit position upon HOLD high, eliminating retransmission overhead |
| Power-on write disable | Internal latch resets at power-up, requiring explicit WREN before any write - prevents corruption during brown-out or startup |
| Low-power standby mode | 500 nA typical ICCS enables battery-backed applications such as energy meters or portable diagnostics tools |
Applications
| Industrial Control Configuration | Medical Device Calibration Storage |
|---|---|
Use Scenario: Storing PID loop coefficients, sensor offset values, and user-defined alarm thresholds in PLC I/O modules. IC Role / Device Role / Timing Role: Nonvolatile configuration register holding persistent settings across power cycles. Use Value: Enables field recalibration without firmware reflashing; BP bits lock critical parameters against unintended modification. |
Use Scenario: Retaining factory-calibrated gain/offset values for ECG amplifier channels and temperature sensor linearization tables. IC Role / Device Role / Timing Role: Secure, long-retention data vault for safety-critical calibration constants. Use Value: Meets >200-year data retention requirement for Class II medical devices; WP pin provides hardware-enforced write lock during operation. |
| Smart Energy Meter Firmware Patch | Automotive Body Control Module Settings |
Use Scenario: Hosting minor firmware updates or regional tariff tables downloaded over HAN (Home Area Network) interfaces. IC Role / Device Role / Timing Role: Field-upgradable code/data partition accessible via microcontroller SPI port. Use Value: 5 ms write time allows sub-second patch application; 1M endurance supports decades of field updates under DLMS/COSEM protocols. |
Use Scenario: Saving seat/mirror position presets, lighting profiles, and door lock behavior preferences in BCMs. IC Role / Device Role / Timing Role: User preference storage with fast random-access read and infrequent write. Use Value: 2 MHz SPI speed enables <10 ms full-table read; HOLD pin ensures uninterrupted operation during CAN bus interrupt handling. |
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/ST | 1.8–5.5 V supply range; 1 MHz max clock; same TSSOP-8 ST pinout | Better suited for mixed-voltage systems with 1.8 V logic; lower speed acceptable for configuration-only use | Select when wider VCC range or compatibility with 1.8 V microcontrollers is required |
| 25LC040A-I/ST | Enhanced revision with improved ESD rating (6 kV HBM); same electrical specs and ST pinout | Recommended for new designs per Microchip notice; identical drop-in replacement with higher robustness | Prefer for production builds where long-term supply continuity and enhanced reliability are prioritized |
Compared with 25LC040XT-I/ST, the 25AA040T-I/ST offers broader voltage support but reduced speed, while the 25LC040A-I/ST delivers identical performance with superior ESD immunity and official design-in recommendation - making it the preferred upgrade path.
Availability
25LC040XT-I/ST is available at Aetrix Electronics and suitable for industrial control configuration, medical device calibration storage, smart energy meter firmware patching, and automotive body control module settings requiring stable component supply and long-term data integrity.
Supply support for 25LC040XT-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 leading provider of microcontrollers, analog components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25LC040XT-I/ST belongs to Microchip's legacy 25XX040 serial EEPROM product line, designed specifically for cost-sensitive, space-constrained embedded systems needing reliable nonvolatile storage with SPI simplicity and industrial-grade reliability.
FAQ
What is the pinout configuration of the 25LC040XT-I/ST?
The 25LC040XT-I/ST uses the "ST" alternate pinout in TSSOP-8: Pin 1 = HOLD, Pin 2 = VCC, Pin 3 = CS, Pin 4 = SO, Pin 5 = WP, Pin 6 = VSS, Pin 7 = SI, Pin 8 = SCK. This differs from standard TSSOP (where HOLD is on pin 7), and must be verified against PCB layout to avoid connection errors.
Does the 25LC040XT-I/ST support SPI Mode 0,0 and Mode 1,1?
Yes, the 25LC040XT-I/ST supports both SPI Mode 0,0 (CPOL = 0, CPHA = 0) and Mode 1,1 (CPOL = 1, CPHA = 1). Data is sampled on the rising edge of SCK and shifted out on the falling edge, matching standard microcontroller SPI peripherals without requiring custom timing firmware.
How does the write protection work on the 25LC040XT-I/ST?
The 25LC040XT-I/ST implements dual-layer write protection: hardware via the WP pin (disables all writes when low), and software-configurable block protection via BP0/BP1 bits in the STATUS register. When WP is high, BP bits determine whether 0%, 25%, 50%, or 100% of the 512-byte array is write-protected - providing flexible security for firmware and calibration data.
What is the maximum write speed for the 25LC040XT-I/ST?
The 25LC040XT-I/ST supports up to 2 MHz SPI clock frequency at VCC = 2.5–4.5 V, enabling fast instruction and address transmission. However, internal write cycles take up to 5 ms regardless of clock speed - meaning effective write throughput is limited by this self-timed erase-and-write operation, not interface bandwidth.
Is the 25LC040XT-I/ST recommended for new designs?
No - Microchip explicitly states "Not recommended for new designs" in DS21204E, advising migration to the enhanced 25LC040A-I/ST. While 25LC040XT-I/ST remains functional and supported for existing production, the 'A' revision offers improved ESD robustness (6 kV vs. 4 kV) and is designated for future design-ins.
25LC040XT-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:
- 2 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
25LC040XT-I/ST FAQ
1.How can I place an order for 25LC040XT-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC040XT-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 25LC040XT-I/ST reliable?
The price and inventory of 25LC040XT-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 25LC040XT-I/ST is usually 5 days.
3.What payment methods are accepted for 25LC040XT-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC040XT-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC040XT-I/ST?
25LC040XT-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC040XT-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 25LC040XT-I/ST?
For technical support, including 25LC040XT-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC040XT-I/ST requirements.
6.How does Aetrix verify that 25LC040XT-I/ST is sourced from the original manufacturer or authorized distributors?
All 25LC040XT-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 25LC040XT-I/ST meets industry standards.
7.What is the process for return or replacement of 25LC040XT-I/ST?
All 25LC040XT-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 25LC040XT-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 25LC040XT-I/ST part is unused and in its original packaging.
Return procedure for 25LC040XT-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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