My Inquiry
My Account
Microchip Technology 25LC040AX-I/ST
- Part No.:
- 25LC040AX-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25LC040AX-I/ST.pdf
- Description:
- IC EEPROM 4KBIT SPI 10MHZ 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,130
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
25LC040AX-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 HOLD suspend functionality - used for firmware storage and configuration retention in microcontroller-based embedded systems.
For engineers reviewing the 25LC040AX-I/ST datasheet, 25LC040AX-I/ST pinout, 25LC040AX-I/ST application, or 25LC040AX-I/ST equivalent, this page delivers verified electrical specs, SPI timing constraints, package-confirmed pin mapping (8-lead TSSOP), endurance data (1M cycles), and real-world use cases in industrial control, sensor calibration, and power management subsystems.
Technical Context
The 25LC040AX-I/ST implements a standard SPI Mode 0,0/Master-Slave interface with separate SI (data in) and SO (data out) lines, requiring CS, SCK, and optional HOLD/WP control. Its internal architecture includes a 512-byte EEPROM array, page latches, status register (WIP/WEL/BP0/BP1), and high-voltage generator for write/erase operations.
Write enable logic requires explicit WREN instruction before each write sequence; the write enable latch resets automatically after successful WRITE or WRSR execution, or when WP is pulled low. Page boundaries are fixed at 16-byte intervals (e.g., 0x00–0x0F, 0x10–0x1F), and crossing boundaries during page write causes wraparound within the same page.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit), sufficient for bootloader flags, device IDs, and calibration coefficients in space-constrained designs. |
| Interface | SPI-compatible serial bus (Mode 0,0), enabling direct connection to PIC® and other MCU SPI peripherals without protocol translation. |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5V, allowing fast read/write throughput (up to 1.25 MB/s theoretical burst read) in high-speed embedded hosts. |
| Write Cycle Time | ≤5 ms per byte or page, enabling deterministic firmware update latency and predictable system-level timeout handling. |
| Endurance & Retention | 1,000,000 erase/write cycles and >200 years data retention at 25°C, supporting long-life industrial deployments without refresh logic. |
| Supply Voltage Range | 2.5V to 5.5V, compatible with both 3.3V and 5V logic domains and simplifying mixed-voltage board design. |
| Operating Temperature | –40°C to +85°C (Industrial grade), validated for use in factory automation, motor drives, and outdoor instrumentation. |
Pinout & Package
25LC040AX-I/ST is packaged in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm pitch, marked "ST" in Microchip's package code table. Pin 1 is identified by laser mark; body dimensions are 4.4 mm × 3.0 mm × 1.2 mm (max).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select Input | Active-low enable signal; must be held low for full SPI transaction; rising edge initiates internal write cycle after valid command sequence. |
| SO (Pin 2) | Serial Data Output | Tri-state open-drain output; data shifted out MSB-first on falling edge of SCK; enters high-Z when CS is high or HOLD is asserted. |
| WP (Pin 3) | Hardware Write-Protect | Low = all writes disabled (array + STATUS register); overrides WEL state; does not interrupt ongoing write cycles. |
| VSS (Pin 4) | Ground Reference | Primary return path for all I/O and core circuitry; must be low-impedance and decoupled near VCC pin. |
| SI (Pin 5) | Serial Data Input | CMOS input accepting instructions, addresses, and data; sampled on rising edge of SCK; supports daisy-chaining via shared SCK/CS lines. |
| SCK (Pin 6) | Serial Clock Input | Master-generated clock; defines timing for SI sampling and SO updates; max 10 MHz rate with defined rise/fall times ≤100 ns. |
| HOLD (Pin 7) | Communication Suspend | Low = pauses active SPI transfer without resetting address pointer; requires SCK low to assert; resumes on next SCK edge after release. |
| VCC (Pin 8) | Supply Voltage | 2.5V–5.5V power rail; requires local 0.1 µF ceramic decoupling; standby current ≤5 µA at 5.5V enables ultra-low-power sleep modes. |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Mode | Up to 16 bytes written per command, reducing SPI overhead and host CPU load versus byte-by-byte writes. |
| Block Write Protection | Configurable via STATUS register (BP1/BP0) to protect none, upper 1/4, upper 1/2, or entire 512-byte array - prevents accidental firmware corruption. |
| Power-On Write Protection | Write enable latch resets at power-up, and WP pin forces immediate disable - eliminates spurious writes during brown-out or reset conditions. |
| HOLD Functionality | Enables host MCU to service higher-priority interrupts mid-transaction without losing state or reinitializing SPI framing. |
| ESD Robustness | ≥4 kV HBM rating on all pins, ensuring reliability in handling-sensitive industrial assembly and field-repair environments. |
Applications
| Industrial Sensor Calibration | Embedded Firmware Storage |
|---|---|
Use Scenario: Storing temperature-compensation coefficients and sensor offset values in programmable logic controllers (PLCs) and analog front-end modules. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during system boot and periodic recalibration routines via SPI. Use Value: Enables field-updatable calibration without replacing hardware; 1M endurance supports >10 years of daily recalibration cycles at 25°C. | Use Scenario: Holding bootloader parameters, secure keys, and version identifiers in medical diagnostic equipment and HVAC controllers. IC Role / Device Role / Timing Role: SPI-connected persistent memory mapped into MCU's peripheral address space for secure boot verification. Use Value: Hardware write-protection (WP pin + BP bits) prevents unauthorized firmware modification; 5 µA standby current extends battery backup runtime. |
| Motor Drive Configuration | Smart Power Metering |
Use Scenario: Saving motor phase alignment settings, current limit thresholds, and fault log history in variable-frequency drives (VFDs). IC Role / Device Role / Timing Role: Dedicated EEPROM interfaced to drive MCU's SPI port for real-time parameter persistence across power cycles. Use Value: 10 MHz SPI interface allows rapid loading of 512-byte configuration sets (<50 µs read time), minimizing startup delay. | Use Scenario: Recording tariff schedules, meter ID, and tamper-event timestamps in ANSI C12.20-compliant electricity meters. IC Role / Device Role / Timing Role: Tamper-resistant nonvolatile memory storing regulatory-critical data with hardware-enforced write lock. Use Value: WP pin tied to secure voltage monitor ensures write-disable during undervoltage events; >200-year data retention meets utility-grade archival requirements. |
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 (1.8–5.5V); identical pinout, timing, and memory map; supports lower-voltage MCUs. | Required in 1.8V/2.5V systems where 25LC040AX-I/ST's 2.5V min. VCC is insufficient. | Select when operating below 2.5V or needing extended low-VCC compatibility without layout change. |
| AT25040B-SSHL-T | Same 4 Kbit SPI EEPROM, but Atmel (Microchip post-acquisition) part with 2.7–5.5V VCC and slightly higher ICC (6 mA read @ 5.5V). | Valid drop-in alternative only if 2.7V minimum supply is acceptable; different marking and traceability codes. | Choose for legacy Atmel-designated BOMs or when sourcing from distributors with stronger AT25040B stock positions. |
Compared with 25LC040AX-I/ST, the 25AA040AT-I/ST enables operation down to 1.8V for ultra-low-power IoT nodes, while the AT25040B-SSHL-T offers identical function with minor supply and current differences - both require validation of WP/HOLD timing margins in high-noise industrial environments.
Availability
25LC040AX-I/ST is available at Aetrix Electronics and suitable for industrial control, sensor calibration, and motor drive applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for 25LC040AX-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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25LC040A family was designed for reliable, low-pin-count nonvolatile storage in cost-sensitive embedded systems - emphasizing SPI simplicity, hardware write protection, and industrial-grade reliability over high-speed parallel interfaces.
FAQ
What is the maximum clock frequency supported by the 25LC040AX-I/ST?
The 25LC040AX-I/ST supports up to 10 MHz clock frequency when VCC is 4.5V to 5.5V. At 2.5V ≤ VCC < 4.5V, the maximum clock drops to 5 MHz, and at 1.8V ≤ VCC < 2.5V (not applicable to 25LC040AX-I/ST due to its 2.5V minimum), it would be 3 MHz. These limits ensure setup/hold timing compliance across voltage and temperature ranges.
Does the 25LC040AX-I/ST support page write operations, and what is the page size?
Yes, the 25LC040AX-I/ST supports page write mode with a fixed page size of 16 bytes. The device allows up to 16 consecutive bytes to be loaded in a single write command, provided they reside entirely within one physical page boundary (e.g., addresses 0x00–0x0F). Crossing page boundaries wraps data to the start of the same page.
How does the WP pin affect write operations on the 25LC040AX-I/ST?
The WP (Write-Protect) pin on the 25LC040AX-I/ST disables all write operations - including array writes and STATUS register updates - when held low, regardless of the WEL bit state. It does not interrupt ongoing internal write cycles but prevents new write commands from being accepted until WP returns high.
What is the endurance and data retention specification for the 25LC040AX-I/ST?
The 25LC040AX-I/ST is rated for 1,000,000 erase/write cycles and guarantees data retention exceeding 200 years at 25°C. These specifications are validated per JEDEC standards and apply across the full industrial temperature range (–40°C to +85°C), with derating expected at elevated temperatures.
Is the 25LC040AX-I/ST pin-compatible with other members of the 25XX040A family?
Yes, the 25LC040AX-I/ST shares identical pinout, package footprint (8-lead TSSOP), and SPI interface behavior with all 25XX040A variants including 25AA040A and 25LC040A in ST packaging. Differences are limited to VCC range and temperature grade - no PCB redesign is needed when substituting within the same package code.
25LC040AX-I/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:
- 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
25LC040AX-I/ST FAQ
1.How can I place an order for 25LC040AX-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC040AX-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 25LC040AX-I/ST reliable?
The price and inventory of 25LC040AX-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 25LC040AX-I/ST is usually 5 days.
3.What payment methods are accepted for 25LC040AX-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC040AX-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC040AX-I/ST?
25LC040AX-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC040AX-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 25LC040AX-I/ST?
For technical support, including 25LC040AX-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC040AX-I/ST requirements.
6.How does Aetrix verify that 25LC040AX-I/ST is sourced from the original manufacturer or authorized distributors?
All 25LC040AX-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 25LC040AX-I/ST meets industry standards.
7.What is the process for return or replacement of 25LC040AX-I/ST?
All 25LC040AX-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 25LC040AX-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 25LC040AX-I/ST part is unused and in its original packaging.
Return procedure for 25LC040AX-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25LC040AX-I/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…
