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Microchip Technology 25AA128T-I/SN
- Part No.:
- 25AA128T-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
25AA128T-I/SN.pdf
- Description:
- IC EEPROM 128KBIT SPI 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:8,446
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Product details
Overview
25AA128T-I/SN from Microchip Technology Inc. is a 128 Kbit SPI Serial EEPROM with 16,384 × 8-bit organization, 64-byte page size, and industrial temperature range (−40°C to +85°C). It operates from 1.8V to 5.5V, supports up to 10 MHz clock at 4.5–5.5V, and delivers 5 µA standby current. It is used in microcontroller-based systems for firmware storage, calibration data retention, and configuration parameter backup.
For engineers reviewing the 25AA128T-I/SN datasheet, 25AA128T-I/SN pinout, 25AA128T-I/SN application, or 25AA128T-I/SN equivalent, this page provides verified electrical specs, SPI timing constraints, write-protection behavior, HOLD functionality, and package-specific layout guidance for SOIC-8 (SN) implementation.
Technical Context
The 25AA128T-I/SN implements a standard SPI Mode 0,0 interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, SI, SO, WP, HOLD, VCC, and VSS. Its internal architecture includes a status register with WIP, WEL, BP0/BP1, and WPEN bits, enabling programmable block protection and hardware write-disable via the WP pin when WPEN = 1.
It features self-timed internal write cycles (≤5 ms), sequential read capability with automatic address rollover, and robust data integrity mechanisms including power-on write protection, write-enable latch control, and ESD tolerance >4 kV. The device supports page writes within 64-byte boundaries and requires explicit WREN before each write sequence.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 128 Kbit (16,384 × 8-bit), directly addressable via 16-bit SPI command addressing |
| Interface | SPI-compatible serial bus (Mode 0,0), with dedicated SI/SO lines and CS-controlled selection |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5V; reduced to 5 MHz at 2.5–4.5V and 3 MHz at 1.8–2.5V - dictates maximum throughput in host firmware |
| Page Size | 64 bytes - limits contiguous write length without crossing physical page boundary; crossing causes wraparound overwrite |
| Write Endurance | 1,000,000 erase/write cycles - enables long-term field deployment in logging or calibration applications |
| Data Retention | >200 years at 25°C - ensures nonvolatile storage integrity across product lifecycle without refresh |
| Supply Voltage Range | 1.8V to 5.5V - supports direct interfacing with 1.8V, 3.3V, and 5V microcontrollers without level-shifting |
Pinout & Package
25AA128T-I/SN is packaged in an 8-lead narrow SOIC (SN) per Microchip drawing C04-057-SN Rev D, with 1.27 mm pitch, 3.90 mm body width, and recommended land pattern C04-2057-SN Rev B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CS) | Chip Select Input | Active-low enable; must be low for all SPI operations; rising edge initiates internal write cycle after valid write sequence |
| 2 (SO) | Serial Data Output | Tri-state open-drain output; shifts out read data on falling SCK edge; high-impedance when CS high or HOLD active |
| 3 (WP) | Write-Protect Pin | Hardware lock for STATUS register when WPEN = 1; low = disable nonvolatile STATUS writes; no effect on memory array if WPEN = 0 |
| 4 (VSS) | Ground | Reference return path for all digital and analog circuitry; must be low-impedance connection to system GND plane |
| 5 (SI) | Serial Data Input | Latches instruction, address, and data on rising SCK edge; MSB-first protocol; requires setup/hold timing per AC table |
| 6 (SCK) | Serial Clock Input | Synchronizes all SPI transfers; rising edge clocks SI, falling edge updates SO; max frequency depends on VCC |
| 7 (HOLD) | Hold Input | Pauses ongoing SPI sequence without reset; must be asserted while SCK is low; tri-states SO during hold |
| 8 (VCC) | Supply Voltage | Power input for core logic and EEPROM array; bypass capacitor (0.1 µF) required near pin for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Block Write Protection | Selectable via BP0/BP1 bits: protect none, upper 1/4 (3000h–3FFFh), upper 1/2 (2000h–3FFFh), or full array (0000h–3FFFh) |
| HOLD Functionality | Enables interrupt servicing mid-transfer; preserves internal state and resumes from exact byte position upon deassertion |
| Low-Power Operation | 5 µA standby current at 85°C ensures minimal battery drain in always-on embedded systems |
| Robust Data Integrity | Power-on write disable, WREN/WRDI latch control, and automatic WEL reset after each write prevent accidental overwrites |
| Industrial Temp Grade | Qualified for −40°C to +85°C operation - suitable for automotive ECUs, industrial PLCs, and outdoor IoT nodes |
Applications
| Smart Meter Firmware Storage | Medical Device Calibration Data |
|---|---|
|
Use Scenario: Storing firmware update images and boot code in utility-grade electricity meters operating continuously in outdoor enclosures. IC Role / Device Role / Timing Role: Nonvolatile program storage element interfaced to an ARM Cortex-M0+ MCU via SPI, accessed during cold boot and OTA updates. Use Value: 128 Kbit capacity accommodates dual-bank firmware images; 1M-cycle endurance supports 10+ years of field updates; >200-year data retention eliminates need for periodic refresh. |
Use Scenario: Retaining sensor calibration coefficients and user-configurable thresholds in portable ultrasound and ECG devices. IC Role / Device Role / Timing Role: Configuration memory co-located with ADC and signal processor; accessed at power-up and during maintenance mode. Use Value: 1.8V–5.5V supply range matches Li-ion battery voltage swing; WP pin + BP bits prevent accidental erasure during field service; 5 µA standby extends battery life between charges. |
| Automotive Body Control Module | Industrial PLC I/O Configuration |
|
Use Scenario: Saving seat/mirror position presets, lighting profiles, and door lock settings in AEC-Q100-compliant BCMs. IC Role / Device Role / Timing Role: SPI-connected EEPROM storing user preferences and fault logs; accessed by 8-bit or 32-bit automotive MCU. Use Value: AEC-Q100 qualification ensures reliability under thermal cycling and vibration; HOLD pin allows MCU to handle CAN interrupts without aborting EEPROM reads. |
Use Scenario: Holding I/O mapping tables, scaling factors, and alarm thresholds in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Persistent configuration store for real-time control firmware; updated only during commissioning or firmware upgrade. Use Value: Block protection prevents corruption during brown-out events; 64-byte page writes optimize programming time for partial configuration updates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA128-I/SN | No temperature suffix 'T'; identical electrical specs and pinout; same industrial grade but lacks tape-and-reel packaging indicator | Same use cases; differs only in packaging format (tube vs. tape-and-reel); no functional impact on design | Select 25AA128-I/SN for manual prototyping or low-volume builds where reel packaging is unnecessary |
| AT25DF041A-SSH-T | 4 Mbit density, quad SPI support, faster 50 MHz clock, but requires different command set and lacks HOLD pin | Higher throughput needed for firmware caching; not drop-in due to command protocol and pin count mismatch (8-pin vs. 8-pin but different function mapping) | Choose only when migrating to higher-density, faster-read applications and redesigning SPI driver firmware |
Compared with 25AA128T-I/SN, the 25AA128-I/SN offers identical functionality in tube packaging, while AT25DF041A-SSH-T provides greater density and speed at the cost of command compatibility and HOLD functionality - making it unsuitable for direct replacement without firmware and layout changes.
Availability
25AA128T-I/SN is available at Aetrix Electronics and suitable for smart meter firmware storage, medical device calibration data retention, and automotive body control module configuration requiring stable component supply across extended production lifecycles.
Supply support for 25AA128T-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 25AA128T-I/SN belongs to Microchip's legacy SPI EEPROM product line, designed specifically for reliable, low-power, byte-addressable nonvolatile storage in resource-constrained embedded systems.
FAQ
What is the maximum clock frequency supported by the 25AA128T-I/SN?
The 25AA128T-I/SN supports up to 10 MHz clock frequency when VCC is 4.5V to 5.5V. At 2.5V ≤ VCC < 4.5V, the maximum is 5 MHz, and at 1.8V ≤ VCC < 2.5V, it drops to 3 MHz. These limits are defined in Table 1-2 of the DS20001831F datasheet and directly affect achievable SPI throughput in host firmware. The 25AA128T-I/SN must be configured accordingly in the MCU's SPI peripheral registers.
Does the 25AA128T-I/SN support hardware write protection?
Yes, the 25AA128T-I/SN supports hardware write protection via the WP pin when the WPEN bit in its STATUS register is set to 1. When WP is low and WPEN = 1, writes to nonvolatile STATUS register bits are disabled - protecting configuration settings. Memory array writes remain enabled unless blocked by BP0/BP1 bits. This dual-layer protection is confirmed in Section 2.3 and Table 3-2 of the datasheet.
What is the page size and why does it matter for writing to the 25AA128T-I/SN?
The 25AA128T-I/SN has a fixed 64-byte page size. Page writes must stay within a single physical page boundary (e.g., addresses 0x0000–0x003F); crossing boundaries causes data to wrap around and overwrite earlier bytes in the same page. This constraint requires firmware to split multi-page writes - a critical detail for reliable data logging or firmware updates using the 25AA128T-I/SN.
How does the HOLD pin function on the 25AA128T-I/SN?
The HOLD pin on the 25AA128T-I/SN suspends an ongoing SPI transaction without resetting the internal state. When pulled low while SCK is low, SI/SO/SCK are tri-stated and ignored until HOLD returns high (also while SCK is low). This allows the host MCU to service higher-priority interrupts and resume exactly where it left off - a feature explicitly documented in Section 2.6 and Figure 1-1 of the 25AA128/25LC128 datasheet.
Is the 25AA128T-I/SN RoHS compliant and AEC-Q100 qualified?
Yes, the 25AA128T-I/SN is RoHS compliant and AEC-Q100 qualified for the Industrial temperature range (−40°C to +85°C). This qualification is stated in the "Features" section on page 1 of DS20001831F and confirmed in the Device Selection Table. It meets stress test requirements for automotive electronics, including thermal cycling and humidity exposure, making it suitable for under-hood and cabin applications.
25AA128T-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:
- 128Kbit
- Memory Organization:
- 16K 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
25AA128T-I/SN FAQ
1.How can I place an order for 25AA128T-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 25AA128T-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 25AA128T-I/SN reliable?
The price and inventory of 25AA128T-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 25AA128T-I/SN is usually 5 days.
3.What payment methods are accepted for 25AA128T-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25AA128T-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25AA128T-I/SN?
25AA128T-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25AA128T-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 25AA128T-I/SN?
For technical support, including 25AA128T-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25AA128T-I/SN requirements.
6.How does Aetrix verify that 25AA128T-I/SN is sourced from the original manufacturer or authorized distributors?
All 25AA128T-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 25AA128T-I/SN meets industry standards.
7.What is the process for return or replacement of 25AA128T-I/SN?
All 25AA128T-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 25AA128T-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 25AA128T-I/SN part is unused and in its original packaging.
Return procedure for 25AA128T-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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