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Microchip Technology 25AA640AT-I/SN
- Part No.:
- 25AA640AT-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
25AA640AT-I/SN.pdf
- Description:
- IC EEPROM 64KBIT SPI 10MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,774
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Product details
Overview
25AA640AT-I/SN from Microchip Technology Inc. is a 64-Kbit SPI serial EEPROM with 8192 × 8-bit organization, 32-byte page size, and 1.8V–5.5V supply range. It supports up to 10 MHz clock (at VCC ≥ 4.5V), features hardware write protection via WP pin and STATUS register, and delivers 1 million erase/write cycles with >200-year data retention - deployed in automotive infotainment control modules for nonvolatile configuration storage.
For engineers reviewing the 25AA640AT-I/SN datasheet, 25AA640AT-I/SN pinout, 25AA640AT-I/SN application, or 25AA640AT-I/SN equivalent, key selection criteria include industrial temperature support (–40°C to +85°C), SOIC-8 narrow-body packaging, SPI interface timing compliance, and block-level write protection granularity (none/1/4/1/2/all array).
Technical Context
The 25AA640AT-I/SN implements a standard SPI Mode 0,0 (CPOL=0, CPHA=0) interface with separate SI (data in) and SO (data out) lines, controlled by CS, SCK, and HOLD. Its internal architecture includes an 8-bit instruction register, page latches, and high-voltage generator for EEPROM programming.
It supports sequential read, byte/page write, and status register access (RDSR/WRSR). Write operations require WREN pre-enable, and internal self-timed write cycles complete in ≤5 ms. The HOLD pin suspends ongoing transfers without resetting the sequence, enabling interrupt servicing on host microcontrollers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8192 × 8-bit), directly addressable via 16-bit SPI command addressing |
| Interface | SPI-compatible serial bus (Mode 0,0), requiring only CS, SCK, SI, SO, WP, HOLD - no I²C or parallel bus overhead |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5V; scales down to 5 MHz (2.5V ≤ VCC < 4.5V) and 3 MHz (1.8V ≤ VCC < 2.5V) |
| Write Cycle Time | ≤5 ms internal self-timed erase/write; no external delay required after CS high assertion |
| Endurance & Retention | 1,000,000 erase/write cycles and >200 years data retention at +85°C - validated for automotive ECU firmware parameter logging |
| Supply Voltage | 1.8V–5.5V operation enables direct interfacing with 1.8V, 3.3V, and 5V microcontrollers without level-shifting |
| Temperature Range | Industrial grade: –40°C to +85°C - qualified per AEC-Q100 for under-hood and dashboard electronics |
Pinout & Package
25AA640AT-I/SN is packaged in an 8-lead plastic small outline (SOIC-N) with 150-mil body width (Microchip package code SN), compliant with JEDEC MS-012AA. Pin 1 is marked by a beveled corner or dot; leads are matte tin (Pb-free).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select Input | Active-low enable: drives device into active mode when low; forces SO to high-Z when high - enables multi-device SPI bus sharing |
| SO (Pin 2) | Serial Data Output | Tri-state output: data shifted out MSB-first on falling edge of SCK; enters high-Z when CS high or HOLD low |
| WP (Pin 3) | Write-Protect Input | Hardware lock: disables STATUS register writes when WPEN=1 and WP=low - prevents accidental firmware config corruption during power transients |
| VSS (Pin 4) | Ground Reference | Primary return path for all I/O and core logic; must be low-impedance connection to system GND plane |
| SI (Pin 5) | Serial Data Input | Command/address/data input: sampled on rising edge of SCK; accepts 8-bit instructions (e.g., 0x03 for READ, 0x02 for WRITE) |
| SCK (Pin 6) | Serial Clock Input | Synchronization signal: defines timing for SI sampling (rising edge) and SO update (falling edge); max 10 MHz at 5.5V |
| HOLD (Pin 7) | Communication Suspend | Pauses ongoing SPI transfer when pulled low while SCK is low - allows host MCU to service higher-priority interrupts without reinitializing the sequence |
| VCC (Pin 8) | Supply Voltage | Core power rail: supports 1.8V–5.5V; internal regulation ensures stable EEPROM programming voltage across full range |
Key Features
| Feature | Design Value |
|---|---|
| Block Write Protection | Selectable via BP1/BP0 bits: protects none, upper 1/4 (1800h–1FFFh), upper 1/2 (1000h–1FFFh), or entire array (0000h–1FFFh) - enables secure bootloader region locking |
| Power-On Write Protection | Automatic WEL reset at power-up, plus built-in write-enable latch (WREN/WRDI) - eliminates spurious writes during brown-out or cold-start conditions |
| Low-Power Operation | 1 µA standby current at 5.5V/85°C and 5 mA active read current at 5.5V/10 MHz - suitable for battery-backed industrial sensors |
| HOLD Functionality | True suspend/resume capability: halts SPI communication mid-sequence without losing address pointer state - critical for real-time deterministic systems |
| AEC-Q100 Qualification | Automotive-grade reliability: qualified for Grade 2 (–40°C to +105°C ambient) per AEC-Q100 Rev G - validated for use in ADAS camera module calibration storage |
Applications
| Automotive Body Control Module | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing door lock actuator calibration offsets, seat position presets, and lighting profiles across ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed via SPI during MCU boot and runtime parameter updates. Use Value: 1M endurance ensures reliable updates over 15+ years of vehicle service life; 1.8V–5.5V range accommodates wide-battery-supply fluctuations. |
Use Scenario: Retaining I/O mapping tables, PID tuning parameters, and alarm thresholds in programmable logic controllers. IC Role / Device Role / Timing Role: SPI EEPROM providing persistent storage independent of main CPU power domain. Use Value: Block protection prevents accidental overwrite of critical safety-related configuration blocks during firmware upgrades. |
| Medical Infusion Pump Settings | Smart Energy Meter Calibration Data |
Use Scenario: Securing drug library definitions, dose limits, and user audit logs in Class II medical devices. IC Role / Device Role / Timing Role: Tamper-resistant nonvolatile memory with hardware write-lock (WP pin + WPEN bit) for regulatory compliance. Use Value: >200-year data retention meets FDA 21 CFR Part 11 long-term recordkeeping requirements; ESD >4 kV withstands clinical environment handling. |
Use Scenario: Storing meter-specific CT/PT ratio coefficients, tariff schedules, and firmware version stamps in ANSI C12.20-compliant meters. IC Role / Device Role / Timing Role: High-reliability SPI memory interfaced to metrology SoC for field-deployed accuracy calibration. Use Value: Industrial temp rating (–40°C to +85°C) ensures stability in outdoor meter enclosures; 32-byte page writes optimize energy-per-write efficiency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25LC640AT-I/SN | Requires minimum 2.5V VCC; identical pinout, timing, and feature set otherwise | Not suitable for 1.8V systems; otherwise drop-in for 3.3V/5V industrial designs | Select 25LC640AT-I/SN only if system VCC never falls below 2.5V - avoids undervoltage write corruption risk present in 25AA640AT-I/SN's wider range |
| AT25DF641A-SHN-T | Quad SPI interface, 3V-only (2.7–3.6V), 64 Mbit density, no HOLD pin | Higher throughput but incompatible protocol; requires firmware rewrite and layout change | Choose only when migrating to faster, denser memory with Quad SPI host support - not a functional substitute for legacy SPI-only systems using 25AA640AT-I/SN |
Compared with 25LC640AT-I/SN, the 25AA640AT-I/SN enables true 1.8V operation and broader supply margin, while AT25DF641A-SHN-T offers higher density and speed at the cost of interface compatibility and design effort.
Availability
25AA640AT-I/SN is available at Aetrix Electronics and suitable for automotive body control units, industrial PLCs, medical infusion pumps, and smart energy meters requiring stable component supply across extended product lifecycles.
Supply support for 25AA640AT-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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25AA640A family was designed specifically for robust, low-power, SPI-based nonvolatile storage in automotive and industrial applications where extended temperature operation, high endurance, and hardware write protection are mandatory.
FAQ
What is the maximum SPI clock frequency supported by the 25AA640AT-I/SN?
The 25AA640AT-I/SN supports up to 10 MHz clock frequency when VCC is 4.5V–5.5V. At 2.5V ≤ VCC < 4.5V, max clock drops to 5 MHz; at 1.8V ≤ VCC < 2.5V, it is limited to 3 MHz. These values are specified in Table 1-2 AC Characteristics and verified across the full industrial temperature range (–40°C to +85°C) for the 25AA640AT-I/SN.
Does the 25AA640AT-I/SN support hardware write protection, and how is it configured?
Yes, the 25AA640AT-I/SN supports dual-layer hardware write protection: (1) the WP pin, enabled when WPEN bit = 1 in the STATUS register and WP = low, and (2) block protection bits BP1/BP0 that lock 0%, 25%, 50%, or 100% of the memory array. This configuration is retained across power cycles and is documented in Tables 3-2 and 3-3 of the 25AA640AT-I/SN datasheet.
What package type does the 25AA640AT-I/SN use, and what are its key mechanical dimensions?
The 25AA640AT-I/SN uses an 8-lead plastic small outline (SOIC-N) package with 150-mil body width (JEDEC MS-012AA, Microchip drawing C04-057-SN). Key dimensions: 4.90 mm length, 3.90 mm width, 1.75 mm height, 1.27 mm lead pitch, and 0.33–0.51 mm lead thickness - fully compatible with standard SOIC-8 PCB footprints and reflow profiles.
How many erase/write cycles can the 25AA640AT-I/SN endure, and under what conditions is this rated?
The 25AA640AT-I/SN is rated for 1,000,000 erase/write cycles at +25°C and VCC = 5.5V, as specified in Table 1-2 (Parameter No. 21). This endurance is guaranteed across the full industrial temperature range (–40°C to +85°C) and applies to both byte and page write operations within the same physical 32-byte page boundary.
Is the 25AA640AT-I/SN AEC-Q100 qualified, and which grade does it meet?
Yes, the 25AA640AT-I/SN is AEC-Q100 qualified per Rev G. It meets Grade 2 requirements (–40°C to +105°C ambient operating temperature), with full characterization and stress testing performed across the industrial temperature range (–40°C to +85°C) as stated in the Device Selection Table and Qualification Summary of the 25AA640AT-I/SN datasheet.
25AA640AT-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:
- 64Kbit
- Memory Organization:
- 8K 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-SOIC
25AA640AT-I/SN FAQ
1.How can I place an order for 25AA640AT-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 25AA640AT-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 25AA640AT-I/SN reliable?
The price and inventory of 25AA640AT-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 25AA640AT-I/SN is usually 5 days.
3.What payment methods are accepted for 25AA640AT-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25AA640AT-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25AA640AT-I/SN?
25AA640AT-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25AA640AT-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 25AA640AT-I/SN?
For technical support, including 25AA640AT-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25AA640AT-I/SN requirements.
6.How does Aetrix verify that 25AA640AT-I/SN is sourced from the original manufacturer or authorized distributors?
All 25AA640AT-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 25AA640AT-I/SN meets industry standards.
7.What is the process for return or replacement of 25AA640AT-I/SN?
All 25AA640AT-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 25AA640AT-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 25AA640AT-I/SN part is unused and in its original packaging.
Return procedure for 25AA640AT-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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