My Inquiry
My Account
Microchip Technology 25LC040XT/ST
- Part No.:
- 25LC040XT/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25LC040XT/ST.pdf
- Description:
- IC EEPROM 4KBIT SPI 2MHZ 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,562
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
25LC040XT/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 rating (−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 - deployed in embedded control systems for parameter storage and firmware configuration.
For engineers reviewing the 25LC040XT/ST datasheet, 25LC040XT/ST pinout, 25LC040XT/ST application, or 25LC040XT/ST equivalent, key selection considerations include its TSSOP-8 package with alternate pinout (HOLD on Pin 1, VCC on Pin 2), 5 ms max internal write cycle time, 1 million endurance cycles, and block-level write protection (none/¼/½/all array).
Technical Context
The 25LC040XT/ST implements a standard SPI Mode 0,0 interface (CPOL = 0, CPHA = 0) with separate SI and SO lines, requiring CS, SCK, SI, SO, WP, HOLD, VCC, and VSS. Its internal architecture includes an 8-bit instruction register, STATUS register with WIP/WEL/BP bits, and page-addressed EEPROM array partitioned into four 128-byte blocks.
Write operations require explicit WREN instruction followed by WRITE command and data; write enable latch resets after each successful write or on WP low. The HOLD pin suspends ongoing serial transfers without resetting the sequence, enabling host CPU to service higher-priority interrupts while preserving transaction state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit organization), sufficient for calibration tables or device ID storage in resource-constrained systems |
| Supply voltage | 2.5–5.5 V - compatible with 3.3 V and 5 V logic domains without level shifting |
| Max clock frequency | 2 MHz at VCC ≥ 2.5 V - enables fast read/write in real-time control loops |
| Page size | 16 bytes - constrains burst writes to single-page boundaries; crossing pages requires multiple write cycles |
| Write cycle time | 5 ms maximum - defines minimum interval between write commands; impacts firmware update latency |
| Endurance & retention | 1 million write/erase cycles; >200 years data retention - suitable for long-life industrial deployments |
| Operating temperature | −40°C to +85°C (Industrial grade) - validated for use in automotive ECUs and factory automation controllers |
Pinout & Package
25LC040XT/ST is supplied in an 8-pin Thin Shrink Small Outline Package (TSSOP) with alternate pinout: 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 layout differs from standard TSSOP (where VCC is Pin 8) and matches Microchip's "X" suffix designation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HOLD (Pin 1) | Serial bus suspend control | Tri-states SO and ignores SI/SCK transitions when low; resumes from exact byte position on release - critical for deterministic interrupt handling |
| VCC (Pin 2) | Power supply input | Accepts 2.5–5.5 V; powers internal charge pump for EEPROM programming; decoupling capacitor required near pin |
| CS (Pin 3) | Device select | Active-low chip select; must be low for all SPI transactions; high-Z SO when deasserted enables multi-device SPI bus sharing |
| SO (Pin 4) | Serial data output | Outputs memory contents MSB-first on falling edge of SCK; high-impedance when CS high or HOLD low |
| WP (Pin 5) | Hardware write protect | Low disables all writes to memory and STATUS register; overrides WREN latch - prevents corruption during power transients |
| VSS (Pin 6) | Ground reference | Return path for all internal circuitry; must be connected directly to system ground plane with low-inductance trace |
| SI (Pin 7) | Serial data input | Receives instructions, addresses, and data MSB-first on rising edge of SCK; latched synchronously to clock |
| SCK (Pin 8) | Serial clock input | Master-generated SPI clock; rising edge latches SI, falling edge updates SO; timing constraints vary with VCC |
Key Features
| Feature | Design Value |
|---|---|
| 16-byte page write | Enables efficient burst writes within page boundaries; reduces total write cycles vs. byte-by-byte programming |
| Block write protection | BP0/BP1 bits in STATUS register allow selective protection of 0%, 25%, 50%, or 100% of memory - secures boot code or calibration data |
| Self-timed write cycles | Internal timing eliminates need for external delay loops; WIP bit in STATUS register indicates completion status |
| Low-power operation | 500 nA standby current and 3 mA typical write current extend battery life in portable instrumentation |
| HOLD pin functionality | Pauses active SPI transfer without losing address pointer or command state - essential for deterministic real-time systems |
Applications
| Industrial Sensor Calibration | Medical Device Configuration |
|---|---|
Use Scenario: Storing sensor offset/gain coefficients and linearization tables in factory-calibrated pressure or temperature sensors. IC Role / Device Role / Timing Role: Nonvolatile parameter storage accessed during power-up or recalibration routines via SPI from MCU. Use Value: Enables field-replaceable sensor modules with unique calibration data preserved across 1M+ cycles and 200+ years. | Use Scenario: Retaining user preferences, alarm thresholds, and device serial numbers in portable ECG monitors and infusion pumps. IC Role / Device Role / Timing Role: Secure configuration memory with hardware write protection (WP pin tied low during normal operation) preventing accidental overwrite. Use Value: Meets IEC 62304 safety requirements for data integrity; BP bits lock critical settings while allowing runtime logging to unprotected pages. |
| Automotive Body Control Module | Smart Energy Meter Firmware Patch Storage |
Use Scenario: Holding seat/mirror position memory, lighting profiles, and door lock settings in 12 V automotive BCMs. IC Role / Device Role / Timing Role: SPI EEPROM interfaced to 8-bit or 32-bit automotive MCU; withstands load-dump and cold-crank conditions via robust VCC range (2.5–5.5 V). Use Value: Industrial temp rating (−40°C to +85°C) and 4 kV ESD protection ensure reliability in under-hood environments. | Use Scenario: Storing firmware patch images and cryptographic keys for secure over-the-air (OTA) updates in utility-grade smart meters. IC Role / Device Role / Timing Role: Dual-purpose memory: protected pages store root keys (BP1/BP0 = 11), unprotected pages hold patch binaries. Use Value: Hardware-based write protection prevents malicious or corrupted OTA payloads from overwriting security assets. |
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; 1 MHz max clock; same TSSOP-8 alternate pinout | Better suited for ultra-low-voltage systems (e.g., coin-cell powered IoT nodes); lower speed limits throughput | Select when operating below 2.5 V or prioritizing lowest standby current (500 nA identical) |
| 25LC040A-I/ST | Enhanced revision with improved ESD (>4 kV HBM), same pinout and electrical specs; recommended for new designs | Drop-in replacement with extended lifecycle support and updated qualification - no design changes required | Preferred for new designs per Microchip's notice; identical footprint and timing but superior robustness |
Compared with 25LC040XT/ST, 25AA040T-I/ST supports lower VCC but trades speed for voltage flexibility, while 25LC040A-I/ST offers identical performance with enhanced reliability and full backward compatibility - making it the optimal upgrade path.
Availability
25LC040XT/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control modules, and smart energy meter firmware patch storage requiring stable component supply across extended product lifecycles.
Supply support for 25LC040XT/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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25LC040XT/ST belongs to Microchip's legacy SPI Serial EEPROM product line, designed specifically for cost-sensitive, space-constrained embedded systems requiring reliable nonvolatile storage with simple 4-wire SPI interface and hardware data protection.
FAQ
What is the pinout configuration of the 25LC040XT/ST?
The 25LC040XT/ST uses an alternate TSSOP-8 pinout: 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 packages and aligns with Microchip's "X" suffix designation for alternate layouts.
Does the 25LC040XT/ST support SPI Mode 0,0 only?
Yes, the 25LC040XT/ST operates exclusively in SPI Mode 0,0 (CPOL = 0, CPHA = 0): data sampled on rising SCK edge (SI), output updated on falling SCK edge (SO). It does not support Mode 1,1 or other variants - confirmed by timing diagrams and functional description in DS21204E.
How does the write protection work on the 25LC040XT/ST?
The 25LC040XT/ST implements dual-layer write protection: hardware via the WP pin (low disables all writes), and software via BP0/BP1 bits in the STATUS register that configure 0%, 25%, 50%, or 100% array protection. Both mechanisms must permit writing for successful nonvolatile updates.
What is the maximum write speed achievable with the 25LC040XT/ST?
The 25LC040XT/ST supports up to 2 MHz SPI clock frequency at VCC ≥ 2.5 V, enabling theoretical peak read throughput of ~200 kB/s. However, write operations are limited by 5 ms internal cycle time per page, resulting in effective write speed of ~3.2 kB/s maximum under ideal page-aligned conditions.
Is the 25LC040XT/ST suitable for automotive applications?
The 25LC040XT/ST is rated for Industrial temperature range (−40°C to +85°C), not Automotive (−40°C to +125°C). For automotive use, Microchip specifies the 25C040 variant - the 25LC040XT/ST is appropriate for under-dash or cabin-control modules meeting industrial spec, but not under-hood applications requiring Grade 0 or Grade 1 qualification.
25LC040XT/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:
- Not 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
25LC040XT/ST FAQ
1.How can I place an order for 25LC040XT/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC040XT/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/ST reliable?
The price and inventory of 25LC040XT/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/ST is usually 5 days.
3.What payment methods are accepted for 25LC040XT/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC040XT/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC040XT/ST?
25LC040XT/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC040XT/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/ST?
For technical support, including 25LC040XT/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC040XT/ST requirements.
6.How does Aetrix verify that 25LC040XT/ST is sourced from the original manufacturer or authorized distributors?
All 25LC040XT/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/ST meets industry standards.
7.What is the process for return or replacement of 25LC040XT/ST?
All 25LC040XT/ST units undergo pre-shipment inspection (PSI). If there is an issue with 25LC040XT/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/ST part is unused and in its original packaging.
Return procedure for 25LC040XT/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25LC040XT/ST Tags
-
M24C02-WMN6TP
STMicroelectronics
-
AT24C02C-XHM-T
Microchip Technology
-
AT21CS01-STUM10-T
Microchip Technology
-
AT24C02C-SSHM-T
Microchip Technology
-
24LC01BT-I/OT
Microchip Technology
-
M24C02-FMC6TG
STMicroelectronics
-
AT24CS02-SSHM-T
Microchip Technology
-
93LC46BT-I/OT
Microchip Technology
-
AT24C04C-SSHM-T
Microchip Technology
-
24LC01BT-I/SN
Microchip Technology
-
24AA02UIDT-I/OT
Microchip Technology
-
AT24C08C-STUM-T
Microchip Technology
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
