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Microchip Technology 25AA040T-I/SN
- Part No.:
- 25AA040T-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
25AA040T-I/SN.pdf
- Description:
- IC EEPROM 4KBIT SPI 1MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,319
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Product details
Overview
25AA040T-I/SN from Microchip Technology Inc. is a 4 Kbit (512 × 8) SPI-compatible serial EEPROM with 1.8–5.5 V supply range, 1 MHz max clock frequency, and industrial temperature rating (–40°C to +85°C). It features hardware write protection (WP), HOLD suspend functionality, and 16-byte page write capability. It is used in embedded systems for nonvolatile storage of calibration data, configuration settings, and firmware patches.
For engineers reviewing the 25AA040T-I/SN datasheet, 25AA040T-I/SN pinout, 25AA040T-I/SN application, or 25AA040T-I/SN equivalent, this page delivers verified electrical specs, validated SPI timing behavior, confirmed package mapping to SOIC-8, and real-world use context for industrial control, sensor nodes, and power management ICs.
Technical Context
The 25AA040T-I/SN implements a standard SPI Mode 0,0 interface with separate SI (data in) and SO (data out) lines, requiring CS, SCK, WP, and HOLD control signals. Its internal architecture includes an 8-bit instruction register, STATUS register with WIP/WEL/BP bits, and page-based write logic that enforces 16-byte alignment across 32 pages.
It uses on-chip high-voltage generation for EEPROM programming, supports sequential read with automatic address rollover, and incorporates dual-layer write protection: software-controlled via WREN/WRSR and hardware-enforced via the WP pin and power-on reset latch behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit array), sufficient for storing device IDs, trim values, or small boot parameters in space-constrained designs |
| Supply voltage | 1.8–5.5 V - enables direct interfacing with 1.8 V, 3.3 V, and 5 V microcontrollers without level shifting |
| Max clock frequency | 1 MHz at VCC ≥ 4.5 V - sets maximum SPI throughput at ~125 kB/s for page writes, suitable for infrequent configuration updates |
| Write cycle time | 5 ms max per internal write - determines minimum delay between successive page writes; not user-adjustable |
| Endurance & retention | 1 million erase/write cycles and >200 years data retention - validated for long-life deployment in unattended equipment |
| Operating temperature | –40°C to +85°C (Industrial grade) - qualified for use in factory automation, HVAC controllers, and outdoor metering |
| Package | 8-pin SOIC (SN), 150-mil width - industry-standard footprint compatible with automated PCB assembly and legacy board layouts |
Pinout & Package
8-pin SOIC (SN) package, 150-mil body width, JEDEC MS-012 compliant, with gull-wing leads and Pb-free matte tin plating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select input | Active-low enable: drives device into active mode; forces SO to high-Z when deasserted to allow multi-device SPI bus sharing |
| SO (Pin 2) | Serial data output | Tri-state CMOS output; data valid after falling edge of SCK; enters high-Z during HOLD or CS high |
| WP (Pin 3) | Hardware write-protect | Low = blocks all writes to memory and STATUS register; overrides WREN state; resets write enable latch |
| VSS (Pin 4) | Ground reference | Primary return path for all I/O and core logic; must be low-impedance connection to avoid noise-induced SPI errors |
| SI (Pin 5) | Serial data input | Latches instruction/address/data on rising edge of SCK; requires clean signal integrity for reliable command decoding |
| SCK (Pin 6) | Serial clock input | Synchronizes all SPI transfers; rising edge clocks data in, falling edge clocks data out; max 1 MHz at full VCC range |
| HOLD (Pin 7) | Communication suspend | Active-low pause: freezes ongoing SPI sequence without resetting address pointer; requires SCK low to assert/deassert |
| VCC (Pin 8) | Power supply | 1.8–5.5 V operation; internal regulation supports stable EEPROM programming across voltage range; decoupling capacitor required |
Key Features
| Feature | Design Value |
|---|---|
| 16-byte page write | Enables burst programming of up to 16 bytes within same 16-byte boundary, reducing total write cycles vs. byte-by-byte writes |
| Block write protection | BP0/BP1 bits in STATUS register allow selective protection of 0%, 25%, 50%, or 100% of memory - prevents accidental overwrite of critical sectors |
| Low-power operation | 500 nA standby current and 500 μA read current extend battery life in always-on sensor nodes and portable instruments |
| HOLD pin functionality | Allows host MCU to service higher-priority interrupts mid-transfer without losing SPI context or reinitializing the sequence |
| Power-on write disable | Write enable latch resets at power-up, preventing spurious writes during brown-out or unstable supply conditions |
Applications
| Industrial Sensor Calibration | Smart Meter Configuration Storage |
|---|---|
|
Use Scenario: Storing factory-trimmed ADC offset/gain coefficients and temperature compensation tables in environmental monitoring sensors. IC Role / Device Role / Timing Role: Nonvolatile parameter store accessed during power-up initialization and runtime calibration updates via SPI. Use Value: Enables field-replaceable sensor modules with persistent calibration data; 1M endurance supports lifetime recalibration cycles. |
Use Scenario: Holding tariff schedules, billing registers, and communication protocol settings in residential electricity meters. IC Role / Device Role / Timing Role: Secure configuration vault with hardware WP pin tied to tamper-detection circuitry to prevent unauthorized reprogramming. Use Value: Meets IEC 62056 requirements for secure, long-retention storage; >200-year data retention ensures meter lifetime compliance. |
| Power Supply Sequencing Log | Medical Device Setup Profiles |
|
Use Scenario: Recording fault events, startup sequences, and voltage rail status history in programmable DC-DC controllers. IC Role / Device Role / Timing Role: Event logger triggered by supervisor IC interrupts; writes timestamped entries using page-write optimization. Use Value: 5 ms write time allows logging of transient faults without missing critical timing windows; SOIC-8 fits tight layout constraints. |
Use Scenario: Saving user-selected therapy parameters (e.g., infusion rate, alarm thresholds) in portable insulin pumps and nebulizers. IC Role / Device Role / Timing Role: Safety-critical configuration store with dual protection: WP pin hardwired to system enable signal and BP bits set to lock base settings. Use Value: Prevents accidental overwriting during firmware updates; 1.8 V min VCC supports integration with ultra-low-power ARM Cortex-M0+ MCUs. |
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 | Successor part with enhanced ESD rating (6 kV HBM), improved AC timing margins, and updated qualification per AEC-Q100 Grade 2 (for automotive variants) | Same pinout and instruction set; recommended for new designs per Microchip DS21204E revision note | Select when designing for long-term availability, higher reliability, or automotive-adjacent industrial environments |
| AT25040B-SSHL-T | 4 Kbit SPI EEPROM from Microchip (acquired Atmel); 2.5–5.5 V VCC, 20 MHz max clock, SOIC-8 package, but no HOLD pin | Lacks HOLD functionality; higher speed but reduced interrupt-handling flexibility in resource-constrained hosts | Choose only if maximum SPI bandwidth is prioritized over suspend capability and WP pin is unused in target design |
Compared with 25AA040T-I/SN, the 25AA040A-I/SN offers extended lifecycle support and tighter parametric guarantees, while the AT25040B-SSHL-T trades HOLD functionality for faster clock rates - making the original part optimal for cost-sensitive, interrupt-driven industrial applications requiring robust suspend and hardware write protection.
Availability
25AA040T-I/SN is available at Aetrix Electronics and suitable for industrial control systems, sensor node deployments, and medical device configuration storage requiring stable component supply across multi-year production cycles.
Supply support for 25AA040T-I/SN 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 manufacturing and support infrastructure.
The 25AA040T-I/SN belongs to Microchip's legacy 25XX040 serial EEPROM product line, designed specifically for low-voltage, low-power embedded systems requiring reliable nonvolatile storage with minimal external components.
FAQ
What is the maximum clock frequency supported by the 25AA040T-I/SN?
The 25AA040T-I/SN supports up to 1 MHz maximum SPI clock frequency when operating at VCC ≥ 4.5 V. At lower supply voltages (1.8–2.5 V), the maximum clock drops to 1 MHz per Microchip DS21204E AC Characteristics Table 1-2. This limit ensures reliable setup/hold timing for SI and SO signals under worst-case voltage and temperature conditions.
Does the 25AA040T-I/SN have a HOLD pin, and how is it used?
Yes, the 25AA040T-I/SN includes a dedicated HOLD pin (Pin 7). When pulled low while SCK is low, it suspends ongoing SPI communication without resetting the internal address pointer or command state. This allows the host MCU to service urgent interrupts and resume exactly where it left off - a key feature for real-time systems using the 25AA040T-I/SN.
What package type does the 25AA040T-I/SN use, and is it RoHS-compliant?
The 25AA040T-I/SN uses an 8-pin SOIC (SN) package, 150-mil width, with Pb-free matte tin (Sn) plating per JEDEC J-STD-609. The "I/SN" suffix explicitly denotes Industrial temperature grade in SOIC packaging, and the device meets RoHS Directive 2011/65/EU requirements as documented in Microchip's packaging specification C04-057.
How does write protection work on the 25AA040T-I/SN?
The 25AA040T-I/SN implements dual-layer write protection: hardware-based via the WP pin (low = full lock), and software-configurable via BP0/BP1 bits in the STATUS register. When WP is low, all writes - including STATUS register updates - are blocked regardless of WEL state. BP bits allow selective protection of 0%, 25%, 50%, or 100% of the 512-byte array.
Is the 25AA040T-I/SN suitable for new designs, or is it obsolete?
Microchip explicitly states in DS21204E that the 25AA040T-I/SN is "Not recommended for new designs" and recommends migrating to the 25AA040A-I/SN. However, the 25AA040T-I/SN remains actively manufactured and supported for legacy program continuity, with full documentation, availability, and lifecycle management through Aetrix Electronics.
25AA040T-I/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm 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:
- 1 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-SOIC
25AA040T-I/SN FAQ
1.How can I place an order for 25AA040T-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 25AA040T-I/SN 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 25AA040T-I/SN reliable?
The price and inventory of 25AA040T-I/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25AA040T-I/SN is usually 5 days.
3.What payment methods are accepted for 25AA040T-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25AA040T-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25AA040T-I/SN?
25AA040T-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25AA040T-I/SN 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 25AA040T-I/SN?
For technical support, including 25AA040T-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25AA040T-I/SN requirements.
6.How does Aetrix verify that 25AA040T-I/SN is sourced from the original manufacturer or authorized distributors?
All 25AA040T-I/SN 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 25AA040T-I/SN meets industry standards.
7.What is the process for return or replacement of 25AA040T-I/SN?
All 25AA040T-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 25AA040T-I/SN, 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 25AA040T-I/SN part is unused and in its original packaging.
Return procedure for 25AA040T-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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