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Microchip Technology 25AA040AT-I/OT
- Part No.:
- 25AA040AT-I/OT
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- SOT-23-6
- Datasheet:
-
25AA040AT-I/OT.pdf
- Description:
- IC EEPROM 4KBIT SPI SOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:11,273
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Product details
Overview
25AA040AT-I/OT from Microchip Technology Inc. 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 requiring low-power, reliable data retention.
For engineers reviewing the 25AA040AT-I/OT datasheet, 25AA040AT-I/OT pinout, 25AA040AT-I/OT application, or 25AA040AT-I/OT equivalent, key selection criteria include SPI interface compatibility, 1.8 V minimum operating voltage, SOT-23-6 package footprint, industrial temperature support, and block-level write protection configuration.
Technical Context
The 25AA040AT-I/OT implements a standard SPI Mode 0,0/Master-Slave interface with separate SI (data-in) and SO (data-out) lines, CS-controlled selection, and HOLD input for transaction suspension. Its internal architecture includes a 512-byte EEPROM array, page latches, status register (WIP/WEL/BP0/BP1), and HV generator for write/erase cycles.
Write operations require explicit WREN instruction followed by CS high to latch enable state; writes are self-timed (≤5 ms), and page boundaries are fixed at 16-byte intervals (addresses ending in 0x00–0x0F). Block protection is configurable via WRSR to protect none, upper 1/4 (180h–1FFh), upper 1/2 (100h–1FFh), or full array (000h–1FFh).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8-bit), sufficient for firmware calibration tables or device configuration registers |
| Interface | SPI-compatible serial bus (Mode 0,0), compatible with PIC® and most MCU SPI peripherals without bit-banging |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5 V, enabling fast read/write in high-throughput control loops |
| 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 |
| Page Write Size | 16 bytes per page - limits burst writes to aligned 16-byte boundaries to prevent wraparound corruption |
| Endurance & Retention | 1,000,000 erase/write cycles and >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, PLCs, and outdoor sensors |
Pinout & Package
25AA040AT-I/OT is housed in a Pb-free, RoHS-compliant 6-lead SOT-23 package (1.6 mm × 2.8 mm × 1.1 mm), optimized for space-constrained PCB layouts. Pin 1 is marked by laser indentation; pin 1 location is top-left when viewed from top with marking side up.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: VDD | Supply Voltage Input | Connects to system 1.8–5.5 V rail; decoupling capacitor (0.1 µF) required within 5 mm |
| 2: CS | Chip Select Input | Active-low enables SPI communication; must be held high between transactions to enter standby mode |
| 3: SO | Serial Data Output | Tri-states when CS high or HOLD low; outputs MSB-first data on falling edge of SCK |
| 4: WP | Write-Protect Input | Hardware lock: pulled low disables all writes (array and STATUS register), even if WEL=1 |
| 5: SI | Serial Data Input | Latches instruction/address/data on rising edge of SCK; requires clean signal integrity per SPI timing specs |
| 6: SCK | Serial Clock Input | Master-generated clock; max 10 MHz at VCC ≥ 4.5 V; rise/fall times ≤100 ns required |
Key Features
| Feature | Design Value |
|---|---|
| Low-Voltage Operation | Functional down to 1.8 V - enables direct integration with ultra-low-power MCUs (e.g., PIC16LF1xxx) without level-shifting |
| Hardware Write Protection | WP pin provides fail-safe, pin-level disable of all writes - critical for preventing corruption during power transients |
| HOLD Functionality | Pauses ongoing SPI transfers without resetting state - allows host MCU to service higher-priority interrupts mid-sequence |
| Configurable Block Protection | BP0/BP1 bits in STATUS register allow selective 0%, 25%, 50%, or 100% array write-lock - supports secure boot loader partitioning |
| High Reliability | 1M endurance cycles and >200-year data retention - validated for use in sealed, maintenance-free equipment |
Applications
| Smart Energy Metering | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Storing tariff schedules, meter calibration coefficients, and tamper-event logs in DIN-rail mounted electricity meters. IC Role / Device Role / Timing Role: Nonvolatile configuration storage with infrequent writes and frequent reads; retains data across mains power loss. Use Value: 1.8 V operation enables direct connection to meter's 3.3 V LDO; WP pin prevents accidental overwrites during firmware updates. |
Use Scenario: Holding module identification, channel scaling factors, and diagnostic history in modular I/O subsystems. IC Role / Device Role / Timing Role: Parameter EEPROM interfaced to ARM Cortex-M4 host via SPI; accessed during cold start and field calibration. Use Value: −40°C to +85°C rating ensures reliability in uncontrolled cabinet environments; 16-byte page writes optimize update efficiency. |
| Automotive Body Control Unit | Medical Infusion Pump |
|
Use Scenario: Saving seat position memory, mirror presets, and lighting profiles in 12 V vehicle networks with wide input transients. IC Role / Device Role / Timing Role: SPI EEPROM co-located with CAN/LIN microcontroller; accessed only during ignition-on initialization. Use Value: 5.5 V absolute max rating tolerates load-dump spikes; block protection isolates user settings from firmware update partitions. |
Use Scenario: Storing drug library parameters, dose limits, and usage audit trails in battery-powered infusion devices requiring FDA compliance. IC Role / Device Role / Timing Role: Safety-critical configuration store with write-cycle polling (WIP bit) to guarantee write completion before motor activation. Use Value: >200-year data retention meets medical device shelf-life requirements; ESD rating >4 kV protects against handling discharge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA040A-I/SN | Same die, 8-lead SOIC package (3.9 mm × 4.9 mm); no HOLD pin; 1.8–5.5 V, −40°C to +85°C | Requires larger PCB area; lacks HOLD functionality for interrupt-aware hosts | Select when board layout permits SOIC and HOLD is unused; identical electrical behavior otherwise |
| AT25040B-SSHL-T | 4 Kbit SPI EEPROM (Atmel/Microchip), 8-lead SOIC, 1.8–5.5 V, −40°C to +85°C; no HOLD pin; 5 ms max write time | Same memory size and voltage range but different command set (e.g., no RDSR/WRSR parity bit) | Choose when migrating legacy AT25040 designs; verify STATUS register access and BP implementation match |
Compared with 25AA040AT-I/OT, the 25AA040A-I/SN offers identical functionality in a larger SOIC package without HOLD, while AT25040B-SSHL-T provides pin-compatible migration path but requires firmware validation of status register behavior and write-protection mapping.
Availability
25AA040AT-I/OT is available at Aetrix Electronics and suitable for smart metering, industrial PLC modules, automotive body controllers, and medical infusion pumps requiring stable component supply across extended product lifecycles.
Supply support for 25AA040AT-I/OT 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, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25AA040A family delivers cost-effective, low-voltage SPI EEPROMs designed specifically for embedded systems needing robust, small-footprint nonvolatile storage with industrial-grade reliability.
FAQ
What is the minimum supply voltage required for reliable operation of the 25AA040AT-I/OT?
The 25AA040AT-I/OT operates reliably from 1.8 V to 5.5 V. At 1.8 V, maximum clock frequency is reduced to 3 MHz, and DC characteristics (e.g., VOL, VOH) shift per Table 1-1. All functionality-including read, write, and status register access-remains fully operational across this range, making 25AA040AT-I/OT suitable for battery-powered or low-voltage MCU interfaces.
Does the 25AA040AT-I/OT support page write operations, and what is the maximum page size?
Yes, the 25AA040AT-I/OT supports page write mode with a fixed page size of 16 bytes. Writes must remain within a single physical page boundary (e.g., addresses 0x00–0x0F, 0x10–0x1F); crossing boundaries causes wraparound to the page start. This constraint applies regardless of how many bytes are sent-up to 16 may be clocked in before CS high initiates the internal 5 ms write cycle.
How does the HOLD pin function during an active SPI transaction on the 25AA040AT-I/OT?
The HOLD pin suspends ongoing SPI communication without resetting the internal state. When pulled low while SCK is low, SI/SO/SCK inputs are ignored and SO enters high-impedance. The transaction resumes from the exact bit position when HOLD is returned high (with SCK still low). This allows the host MCU to service time-critical interrupts without retransmitting commands or addresses-critical for real-time deterministic systems using 25AA040AT-I/OT.
Can the 25AA040AT-I/OT be used in automotive applications requiring AEC-Q200 qualification?
No-the 25AA040AT-I/OT is rated for Industrial temperature range (−40°C to +85°C) and is not AEC-Q200 qualified. For automotive applications, Microchip recommends the 25LC040A-E/OT variant (automotive grade, −40°C to +125°C), which shares identical pinout and functionality but undergoes additional stress testing and lot traceability per AEC-Q200. The 25AA040AT-I/OT remains appropriate for under-hood-adjacent or cabin modules meeting industrial spec.
What happens to the write enable latch after a successful write operation on the 25AA040AT-I/OT?
After any successful WRITE, WRSR, or WRDI instruction-or upon power-up-the write enable latch (WEL bit) is automatically reset to '0'. This means the 25AA040AT-I/OT requires an explicit WREN instruction before each discrete write or page write sequence. The latch is also cleared when WP is pulled low, ensuring hardware-level write disable takes precedence over software-enable state.
25AA040AT-I/OT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- SOT-23-6
- 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:
- 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:
- SOT-23-6
25AA040AT-I/OT FAQ
1.How can I place an order for 25AA040AT-I/OT through Aetrix?
Please submit a Request for Quotation (RFQ) for 25AA040AT-I/OT 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 25AA040AT-I/OT reliable?
The price and inventory of 25AA040AT-I/OT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25AA040AT-I/OT is usually 5 days.
3.What payment methods are accepted for 25AA040AT-I/OT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25AA040AT-I/OT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25AA040AT-I/OT?
25AA040AT-I/OT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25AA040AT-I/OT 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 25AA040AT-I/OT?
For technical support, including 25AA040AT-I/OT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25AA040AT-I/OT requirements.
6.How does Aetrix verify that 25AA040AT-I/OT is sourced from the original manufacturer or authorized distributors?
All 25AA040AT-I/OT 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 25AA040AT-I/OT meets industry standards.
7.What is the process for return or replacement of 25AA040AT-I/OT?
All 25AA040AT-I/OT units undergo pre-shipment inspection (PSI). If there is an issue with 25AA040AT-I/OT, 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 25AA040AT-I/OT part is unused and in its original packaging.
Return procedure for 25AA040AT-I/OT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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