My Inquiry
My Account
Microchip Technology 25AA040AX-I/ST
- Part No.:
- 25AA040AX-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25AA040AX-I/ST.pdf
- Description:
- IC EEPROM 4KBIT SPI 10MHZ 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,999
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
25AA040AX-I/ST from Microchip Technology is a 4 Kbit SPI Serial EEPROM with 512 × 8-bit organization, 1.8–5.5 V supply range, and industrial temperature rating (−40°C to +85°C). It supports up to 10 MHz clock frequency, 16-byte page write, and hardware write protection via WP pin - used for nonvolatile parameter storage in microcontroller-based embedded systems.
For engineers reviewing the 25AA040AX-I/ST datasheet, 25AA040AX-I/ST pinout, 25AA040AX-I/ST application, or 25AA040AX-I/ST equivalent, key selection criteria include SPI interface compatibility, low-voltage operation down to 1.8 V, page-write timing (≤5 ms), HOLD functionality for interrupt-safe bus arbitration, and block-level write protection configuration.
Technical Context
The 25AA040AX-I/ST implements a standard SPI Mode 0,0/Master-Slave interface with separate SI/SO lines and active-low CS. It uses an internal high-voltage generator for EEPROM programming and includes a status register with WIP, WEL, BP0, and BP1 bits for real-time write monitoring and configurable 0%, 25%, 50%, or 100% array protection.
Communication supports byte and page writes (max 16 bytes within same 16-byte-aligned page), sequential read with automatic address rollover, and HOLD pin suspension of ongoing transfers without sequence restart. Write enable requires explicit WREN instruction, and WP pin overrides software protection when asserted low.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit) - sufficient for firmware calibration data, device ID, or configuration registers in space-constrained designs. |
| Interface | SPI-compatible serial bus (Mode 0,0) - interoperable with PIC®, ARM Cortex-M, and other MCU SPI peripherals without level-shifting. |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5 V - enables fast parameter updates during system initialization or field upgrades. |
| Write Cycle Time | ≤5 ms per byte or page - deterministic erase/write latency critical for time-sensitive logging or fail-safe state capture. |
| Supply Voltage Range | 1.8 V to 5.5 V - supports direct interfacing with 1.8 V, 3.3 V, and 5 V logic domains without external regulators. |
| Data Retention | >200 years - ensures long-term reliability for medical, industrial, and infrastructure equipment with multi-decade service life. |
| Endurance | 1,000,000 erase/write cycles - suitable for applications requiring frequent runtime parameter updates (e.g., energy metering, sensor calibration). |
Pinout & Package
25AA040AX-I/ST is packaged in an 8-lead TSSOP (ST package code), 3.0 mm × 4.4 mm body, 0.65 mm pitch, with exposed pad optional for thermal enhancement. Pin 1 is marked by laser dot; pin numbering follows standard counterclockwise orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable: drives device into active mode; rising edge initiates internal write cycle after valid command sequence. |
| 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. |
| WP | Write-Protect Input | Hardware lock: disables all writes (array and STATUS register) when pulled low, independent of WEL or BP bits. |
| VSS | Ground Reference | Primary return path for I/O and core logic; must be low-impedance to minimize noise coupling during write operations. |
| SI | Serial Data Input | CMOS input: accepts instructions, addresses, and data MSB-first on rising SCK edge; sampled only when CS is low. |
| SCK | Serial Clock Input | Synchronous timing reference: defines data setup/hold windows; max 10 MHz at 4.5–5.5 V; rise/fall times ≤100 ns. |
| HOLD | Hold Input | Bus pause control: suspends ongoing SPI transfer when pulled low (SCK must be low); resumes on next SCK low-to-high transition. |
| VCC | Supply Voltage | Core power rail: powers EEPROM array, logic, and HV generator; bypass capacitor (0.1 µF) required near pin for write stability. |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Mode | Up to 16 bytes written atomically within one 16-byte-aligned page - reduces write overhead vs. byte-by-byte programming. |
| Block Write Protection | Selectable 0%, 25%, 50%, or 100% memory protection via BP0/BP1 bits - prevents accidental overwrite of critical boot or calibration data. |
| HOLD Functionality | Pauses active SPI transfer without resetting internal state - enables host MCU to service higher-priority interrupts mid-sequence. |
| Low-Power Standby | 1 µA typical ICCS at 2.5 V and +85°C - minimizes quiescent current in battery-powered or always-on systems. |
| Power-On Write Protection | WEL reset and SO high-impedance at power-up - eliminates spurious writes during voltage ramp and ensures safe default state. |
Applications
| Industrial Sensor Node | Medical Device Calibration |
|---|---|
Use Scenario: Storing factory-calibrated sensor coefficients and real-time offset corrections in a wireless temperature/humidity node. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed via SPI during boot and periodic recalibration; HOLD used to pause reads during RF transmission. Use Value: Enables field-upgradable calibration without firmware changes; 1.8 V operation extends battery life; >200-year retention guarantees accuracy over product lifetime. |
Use Scenario: Holding patient-specific therapy parameters and usage logs in a portable infusion pump. IC Role / Device Role / Timing Role: Secure parameter vault with WP pin hardwired to system controller; RDSR polling ensures no concurrent writes during safety-critical delivery phases. Use Value: Block protection prevents accidental overwrites of dose limits; 1M-cycle endurance supports daily log entries for 27+ years. |
| Smart Energy Meter | Automotive Body Control Module |
Use Scenario: Recording tariff schedules, tamper events, and accumulated kWh in a Class 0.5 electricity meter. IC Role / Device Role / Timing Role: High-reliability data logger interfaced to metrology MCU; page writes batch timestamped energy samples to minimize write cycles. Use Value: 5 ms write time allows logging at 200 Hz; ESD rating >4 kV withstands harsh metering environments; RoHS-compliant for global deployment. |
Use Scenario: Storing seat position presets, mirror angles, and lighting profiles in a vehicle door module. IC Role / Device Role / Timing Role: Configuration EEPROM tied to LIN or CAN gateway MCU; WP pin controlled by system security state to lock settings after personalization. Use Value: 1.8–5.5 V range accommodates automotive battery transients (cold crank to load dump); industrial temp grade ensures operation across cabin extremes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25LC040AT-I/ST | Requires minimum 2.5 V VCC; identical pinout, timing, and feature set otherwise. | Not suitable for 1.8 V systems; otherwise drop-in replacement in 3.3 V/5 V designs with same temperature grade. | Select 25LC040AT-I/ST only if system VCC never falls below 2.5 V; verify hold-time margins at lower voltage. |
| AT25040B-SSHL-T | Same 4 Kbit SPI EEPROM but with 20 MHz max clock, different status register bit layout, and no HOLD pin. | Lacks HOLD functionality - unsuitable where interrupt-safe bus arbitration is required; higher speed benefits only if host supports >10 MHz. | Choose AT25040B-SSHL-T only when maximum throughput is critical and HOLD is unused; revalidate WP and protection logic. |
Compared with 25AA040AX-I/ST, the 25LC040AT-I/ST offers identical functionality at higher minimum voltage, while the AT25040B-SSHL-T trades HOLD capability for higher clock rate - making the 25AA040AX-I/ST optimal for low-voltage, interrupt-resilient embedded storage.
Availability
25AA040AX-I/ST is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration, smart energy meters, and automotive body control modules requiring stable component supply, long-term data integrity, and RoHS-compliant packaging.
Supply support for 25AA040AX-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 25AA040A family was designed specifically for reliable, low-power nonvolatile storage in cost-sensitive embedded systems - emphasizing SPI simplicity, wide voltage operation, and robust data retention under industrial thermal stress.
FAQ
What is the operating voltage range for the 25AA040AX-I/ST?
The 25AA040AX-I/ST operates from 1.8 V to 5.5 V, enabling direct integration with 1.8 V logic families, 3.3 V microcontrollers, and legacy 5 V systems without level shifters. This wide range is confirmed in the DC Characteristics table (Param D010–D012) of DS21827H, with full functionality guaranteed across the entire span at industrial temperatures.
Does the 25AA040AX-I/ST support page write operations?
Yes, the 25AA040AX-I/ST supports page write mode with up to 16 bytes per page. The device enforces strict page boundaries (addresses ending in 0x00–0x0F), and attempting to cross a boundary wraps data to the start of the same page. This behavior is documented in Section 2.3 and Figure 2-3 of DS21827H.
How does the HOLD pin function on the 25AA040AX-I/ST?
The HOLD pin on the 25AA040AX-I/ST pauses ongoing SPI communication without resetting internal state. When pulled low (with SCK low), SI/SO/SCK enter high-impedance, allowing the host MCU to service interrupts. Resuming requires bringing HOLD high while SCK remains low - timing details are specified in Table 1-2 (Params THS, THH, THZ, THV) and Figure 1-1.
What write protection mechanisms does the 25AA040AX-I/ST provide?
The 25AA040AX-I/ST provides 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 (0%, 25%, 50%, or 100% array lock). These operate independently - WP override takes precedence, as defined in Table 2-4 and Section 2.7.
Is the 25AA040AX-I/ST pin-compatible with other 8-lead TSSOP EEPROMs?
The 25AA040AX-I/ST uses standard 8-lead TSSOP pinout (ST package code) matching Microchip's 25LC040A and industry-standard SPI EEPROM footprints. Pin functions (CS, SO, WP, VSS, SI, SCK, HOLD, VCC) align exactly per Table 3-1 in DS21827H, enabling mechanical and electrical interchangeability within the same package variant.
25AA040AX-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:
- 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:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
25AA040AX-I/ST FAQ
1.How can I place an order for 25AA040AX-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 25AA040AX-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 25AA040AX-I/ST reliable?
The price and inventory of 25AA040AX-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 25AA040AX-I/ST is usually 5 days.
3.What payment methods are accepted for 25AA040AX-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25AA040AX-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25AA040AX-I/ST?
25AA040AX-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25AA040AX-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 25AA040AX-I/ST?
For technical support, including 25AA040AX-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25AA040AX-I/ST requirements.
6.How does Aetrix verify that 25AA040AX-I/ST is sourced from the original manufacturer or authorized distributors?
All 25AA040AX-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 25AA040AX-I/ST meets industry standards.
7.What is the process for return or replacement of 25AA040AX-I/ST?
All 25AA040AX-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 25AA040AX-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 25AA040AX-I/ST part is unused and in its original packaging.
Return procedure for 25AA040AX-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25AA040AX-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…
