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Microchip Technology 25AA040XT-I/ST
- Part No.:
- 25AA040XT-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25AA040XT-I/ST.pdf
- Description:
- IC EEPROM 4KBIT SPI 1MHZ 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,654
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Product details
Overview
25AA040XT-I/ST 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. Used for nonvolatile parameter storage in microcontroller-based embedded systems requiring low-power operation and robust data retention.
For engineers reviewing the 25AA040XT-I/ST datasheet, 25AA040XT-I/ST pinout, 25AA040XT-I/ST application, or 25AA040XT-I/ST equivalent, key selection criteria include its TSSOP-8 package with alternate pinout, 5 ms max internal write cycle time, 1 million endurance cycles, and compatibility with SPI Mode 0,0 and Mode 1,1 interfaces in resource-constrained designs.
Technical Context
The 25AA040XT-I/ST implements a standard SPI interface with separate SI (data in) and SO (data out) lines, CS-controlled device selection, and dedicated HOLD and WP control inputs. Its architecture supports sequential read, byte/page write, and STATUS register access for real-time WIP/WEL monitoring.
It uses on-chip high-voltage generation for EEPROM programming and includes power-on reset logic that clears the write enable latch. Block protection (BP1/BP0 bits) enables selective write-protection of 0%, 25%, 50%, or 100% of the memory array - configurable via WRSR instruction and retained across power cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit organization), sufficient for firmware configuration, calibration data, or device ID storage |
| Supply voltage | 1.8–5.5 V - supports 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 - enables fast read/write in low-speed embedded control loops |
| Write cycle time | 5 ms maximum - defines minimum interval between successive page writes; impacts firmware update latency |
| Endurance | 1 million write/erase cycles - ensures reliable logging or counter applications over multi-year product lifetime |
| Data retention | Greater than 200 years - guarantees long-term integrity of stored calibration or security keys without refresh |
| Standby current | 500 nA typical - critical for battery-powered IoT sensors and portable medical devices |
Pinout & Package
25AA040XT-I/ST is housed in an 8-pin Thin Shrink Small Outline Package (TSSOP) with 4.4 mm body width and 0.65 mm pitch. The "XT" suffix denotes the alternate pinout variant per Microchip's product identification system (DS21204E, p.19).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable signal; places device in Standby mode when high, tri-states SO to allow SPI bus sharing |
| SO | Serial Data Output | Push-pull output delivering read data MSB-first on falling edge of SCK; high-impedance when CS high or HOLD active |
| WP | Write-Protect Pin | Hardware lock: disables all writes to memory and STATUS register when pulled low; overrides WREN state |
| VSS | Ground | Reference return path for all digital and internal charge-pump circuitry; must be low-impedance |
| SI | Serial Data Input | Latches instruction, address, and write data on rising edge of SCK; supports SPI Mode 0,0 and 1,1 |
| SCK | Serial Clock Input | Synchronizes all data transfers; rising edge clocks SI, falling edge updates SO; max 1 MHz at full VCC range |
| HOLD | Hold Input | Pauses ongoing SPI transaction without resetting internal address pointer; requires SCK low to assert/deassert |
| VCC | Supply Voltage | Power input for core logic and EEPROM programming; internal regulator enables stable operation across 1.8–5.5 V |
Key Features
| Feature | Design Value |
|---|---|
| 16-byte page write | Enables burst programming of up to 16 contiguous bytes per write cycle, reducing total write time vs. byte-by-byte |
| Block write protection | Configurable via STATUS register (BP1/BP0) to protect 0%, 25%, 50%, or 100% of memory - prevents accidental firmware corruption |
| HOLD suspend function | Allows host MCU to service higher-priority interrupts mid-transaction without losing SPI state or reinitializing sequence |
| Low-power standby | 500 nA typical ICCS enables integration into always-on battery-backed systems without measurable drain |
| ESD robustness | 4 kV HBM rating on all pins - enhances reliability in manufacturing, handling, and field deployment environments |
Applications
| Industrial Sensor Node | Medical Diagnostic Device |
|---|---|
|
Use Scenario: Storing calibrated sensor offsets, linearization coefficients, and usage logs in a battery-powered environmental monitor. IC Role / Device Role / Timing Role: Nonvolatile configuration storage with infrequent writes and frequent reads; timing-critical only during boot-time parameter load. Use Value: 200-year data retention ensures calibration remains valid across device lifetime; 500 nA standby current extends battery life beyond 10 years. |
Use Scenario: Holding patient-specific therapy parameters and audit trail records in a portable glucose meter. IC Role / Device Role / Timing Role: Secure, tamper-resistant parameter store; WP pin physically tied low during normal operation to prevent runtime corruption. Use Value: Hardware write protection (WP) + BP bits ensure therapy settings cannot be altered by software fault or malware; 1M endurance supports daily usage for >27 years. |
| Smart Energy Meter | Automotive Body Control Module |
|
Use Scenario: Recording cumulative kWh consumption, tariff schedules, and firmware version history in a DIN-rail mounted meter. IC Role / Device Role / Timing Role: High-reliability data logger interfaced to an 8-bit MCU via SPI; withstands wide temperature swings and EMI. Use Value: −40°C to +85°C industrial rating matches meter operating envelope; 4 kV ESD protects against field installation transients. |
Use Scenario: Storing seat position presets, mirror calibration, and lighting profiles in a vehicle door module. IC Role / Device Role / Timing Role: Configuration memory accessed during power-up and user adjustment; must survive automotive load dump and cold crank. Use Value: 1.8–5.5 V VCC range accommodates brown-out conditions down to 1.8 V; built-in power-on data protection prevents corruption during unstable supply. |
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/ST | Enhanced revision with improved ESD performance and updated AC timing; same pinout and electrical specs | Preferred for new designs per Microchip notice (DS21204E, p.1); identical functional behavior but higher reliability margin | Select 25AA040A-I/ST if designing new products; 25AA040XT-I/ST remains suitable for legacy BOM continuity and drop-in replacement where qualified |
| AT25040B-SSHL-T | 4 Kbit SPI EEPROM from Microchip (formerly Atmel); 2.5–5.5 V VCC, 20 MHz max clock, SOIC-8 only | Higher speed and wider voltage range, but no HOLD pin and incompatible TSSOP-8 pinout; requires PCB redesign | Choose AT25040B-SSHL-T only when higher throughput is required and layout change is acceptable; not a pin-compatible substitute |
Compared with 25AA040A-I/ST, the 25AA040XT-I/ST offers identical functionality but lacks the latest ESD and timing enhancements; compared with AT25040B-SSHL-T, it trades speed and voltage flexibility for HOLD support and TSSOP-8 alternate pinout compatibility in space-constrained layouts.
Availability
25AA040XT-I/ST is available at Aetrix Electronics and suitable for industrial sensor nodes, medical diagnostic devices, smart energy meters, and automotive body control modules requiring stable component supply and long-term obsolescence management.
Supply support for 25AA040XT-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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design, manufacturing, and sales operations.
The 25AA040XT-I/ST belongs to Microchip's 25XX040 family of SPI serial EEPROMs, designed specifically for low-voltage, low-power embedded systems needing reliable nonvolatile storage with minimal pin count and board area.
FAQ
What is the pinout configuration of the 25AA040XT-I/ST?
The 25AA040XT-I/ST uses the alternate TSSOP-8 pinout defined in Microchip DS21204E (p.19): 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 the standard TSSOP pinout (25AA040T-I/ST) and must be verified against layout footprints.
Does the 25AA040XT-I/ST support SPI Mode 0,0 and Mode 1,1?
Yes, the 25AA040XT-I/ST supports both SPI Mode 0,0 (CPOL = 0, CPHA = 0) and Mode 1,1 (CPOL = 1, CPHA = 1) as confirmed in DS21204E Figure 1-2 and Figure 1-3. Data is sampled on the rising edge of SCK in Mode 0,0 and on the falling edge in Mode 1,1; SO updates after the falling edge in both modes.
How does the HOLD function operate in the 25AA040XT-I/ST?
The HOLD function in the 25AA040XT-I/ST suspends an ongoing SPI transaction without resetting the internal address pointer. To activate, HOLD must be pulled low while SCK is low; SO, SI, and SCK enter high-impedance states. Resuming requires bringing HOLD high while SCK remains low. This allows the host MCU to service interrupts and resume exactly where it left off.
What is the purpose of the WP pin on the 25AA040XT-I/ST?
The WP (Write-Protect) pin on the 25AA040XT-I/ST is a hardware-level safeguard: when held low, it disables all writes to the memory array and STATUS register regardless of WREN status or BP bit settings. It provides fail-safe protection against accidental or malicious firmware corruption during normal operation or power transitions.
Is the 25AA040XT-I/ST recommended for new designs?
No - Microchip explicitly states "Not recommended for new designs" in DS21204E (p.1), advising migration to the enhanced 25AA040A-I/ST or 25AA040A-I/SN. However, the 25AA040XT-I/ST remains fully supported for existing designs, with guaranteed supply and identical functionality to the original 25AA040 series.
25AA040XT-I/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:
- 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-TSSOP
25AA040XT-I/ST FAQ
1.How can I place an order for 25AA040XT-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 25AA040XT-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 25AA040XT-I/ST reliable?
The price and inventory of 25AA040XT-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 25AA040XT-I/ST is usually 5 days.
3.What payment methods are accepted for 25AA040XT-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25AA040XT-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25AA040XT-I/ST?
25AA040XT-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25AA040XT-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 25AA040XT-I/ST?
For technical support, including 25AA040XT-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25AA040XT-I/ST requirements.
6.How does Aetrix verify that 25AA040XT-I/ST is sourced from the original manufacturer or authorized distributors?
All 25AA040XT-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 25AA040XT-I/ST meets industry standards.
7.What is the process for return or replacement of 25AA040XT-I/ST?
All 25AA040XT-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 25AA040XT-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 25AA040XT-I/ST part is unused and in its original packaging.
Return procedure for 25AA040XT-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25AA040XT-I/ST Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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AT24C08C-STUM-T
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