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Microchip Technology 24AA256UIDT-I/SN
- Part No.:
- 24AA256UIDT-I/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
24AA256UIDT-I/SN.pdf
- Description:
- IC EEPROM 256KBIT I2C 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:15,977
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Product details
Overview
24AA256UIDT-I/SN from Microchip Technology Inc. is a 256 Kbit I²C serial EEPROM with factory-programmed EUI-48™ and EUI-64™ node addresses plus a unique 32-bit serial number, operating from 1.7V to 5.5V, supporting up to 400 kHz clock (100 kHz below 2.5V), and housed in an 8-pin SOIC package. It delivers 64-byte page writes, 1M write cycles, and >200-year data retention for secure device identification in embedded systems.
For engineers reviewing the 24AA256UIDT-I/SN datasheet, 24AA256UIDT-I/SN pinout, 24AA256UIDT-I/SN application, or 24AA256UIDT-I/SN equivalent, key selection criteria include guaranteed UID/EUI storage location (0x7FFA–0x7FFF), permanent upper-1/8th array write protection, Schmitt-trigger noise immunity on SDA/SCL, and I²C bus timing compliance across 1.7–5.5V supply range.
Technical Context
The 24AA256UIDT-I/SN implements a standard two-wire I²C slave interface with fixed 0b1010 control code and user-configurable A0–A2 address bits enabling up to eight devices per bus. Its internal architecture includes a 64-byte page latch, address pointer auto-increment, and dedicated HV generator for EEPROM programming.
Write operations support byte and page modes with self-timed erase/write cycles (≤5 ms), while read modes include current-address, random, and sequential access. Acknowledge polling is supported to detect write completion without fixed delay timing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 32K × 8 (256 Kbit) EEPROM array; 229,376 usable bits after UID/EUI reservation |
| Supply Voltage | 1.7V to 5.5V; enables direct interfacing with 1.8V, 3.3V, and 5V microcontrollers |
| I²C Clock Rate | Up to 400 kHz at VCC ≥2.5V; downgraded to 100 kHz below 2.5V per AC specs |
| Page Write Buffer | 64-byte buffer; allows single Stop condition to commit up to 64 bytes within one physical page |
| Endurance & Retention | 1,000,000 write cycles per page; >200 years data retention at +85°C |
| UID Storage | 32-bit serial number at 0x7FFC–0x7FFF; EUI-48™ at 0x7F7A–0x7F7F; EUI-64™ at 0x7FB8–0x7FBF |
| Protection Scheme | Upper 1/8th (0x7000–0x7FFF) permanently write-protected; read-accessible |
Pinout & Package
24AA256UIDT-I/SN is packaged in an 8-pin SOIC (Small Outline Integrated Circuit) with 150-mil body width, RoHS-compliant matte tin finish, and industrial temperature range (−40°C to +85°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Chip Address Input | User-configurable LSB of 3-bit slave address; hardwired to VSS/VCC to select one of eight possible I²C addresses |
| A1 | Chip Address Input | Middle bit of slave address; determines device selection when multiple 24AA256UIDT-I/SN share same bus |
| A2 | Chip Address Input | MSB of slave address; enables cascading up to eight identical devices without address conflict |
| VSS | Ground Reference | Primary return path for all internal circuitry and I/O; must be low-impedance connection |
| SDA | Serial Data Line | Open-drain bidirectional I²C data line requiring external pull-up resistor (2 kΩ typical for 400 kHz) |
| SCL | Serial Clock Input | Input-only I²C clock line; Schmitt-trigger input ensures noise immunity and clean edge detection |
| NC | No Connect | Internally unconnected pin; must remain floating or tied to VSS/VCC per board layout best practice |
| VCC | Power Supply | Single supply input supporting 1.7–5.5V; powers EEPROM core, logic, and I/O buffers |
Key Features
| Feature | Design Value |
|---|---|
| Globally Unique Identifiers | EUI-48™ and EUI-64™ node addresses preprogrammed at factory and stored in write-protected memory region |
| Secure Serial Number | 32-bit unique ID guaranteed across entire Microchip UID-family; enables cryptographic binding and anti-cloning |
| Low-Voltage Operation | Functional down to 1.7V with full I²C timing compliance-supports battery-powered and energy-harvesting designs |
| Noise-Resilient Interface | Schmitt-trigger inputs on SDA/SCL and output slope control eliminate ground bounce and improve signal integrity |
| Robust Write Protection | Hardware-enforced write lock on upper 32 KB (0x7000–0x7FFF); prevents accidental overwrite of UID/EUI data |
Applications
| IoT Edge Node Identity | Industrial Sensor Calibration Storage |
|---|---|
Use Scenario: Deploying thousands of wireless sensor nodes requiring unique MAC addresses and tamper-proof device IDs for cloud registration and firmware authentication. IC Role / Device Role / Timing Role: Provides IEEE-compliant EUI-48™/EUI-64™ addresses and cryptographically bound 32-bit serial number stored in permanently protected memory. Use Value: Eliminates need for external provisioning infrastructure; enables zero-touch onboarding and secure boot chain anchoring using factory-trusted identifiers. | Use Scenario: Storing calibrated coefficients, sensor offset/gain values, and manufacturing test data in programmable logic controllers and field instruments. IC Role / Device Role / Timing Role: Nonvolatile parameter storage accessible via standard I²C during power-up or maintenance mode; supports field recalibration without reprogramming MCU flash. Use Value: Maintains calibration integrity across power cycles and firmware updates; leverages 1M-cycle endurance for frequent recalibration events. |
| Medical Device Traceability | Automotive Telematics Module |
Use Scenario: Embedding UDI (Unique Device Identification) and regulatory compliance metadata in Class II medical equipment for FDA-mandated serialization and recall tracking. IC Role / Device Role / Timing Role: Stores immutable 32-bit serial number and manufacturer code (0x29) in fixed, write-protected memory locations (0x7FFA–0x7FFF). Use Value: Meets ISO/IEC 15459 and FDA 21 CFR Part 830 requirements without software-based security layers; immune to firmware corruption or malicious overwrite. | Use Scenario: Supporting vehicle identification, VIN storage, and OTA update signature verification in automotive telematics control units (TCUs). IC Role / Device Role / Timing Role: Holds EUI-64™ node address for cellular modem MAC layer and unique serial ID for secure key derivation in TLS handshake. Use Value: Enables hardware-rooted identity binding for PKI certificate enrollment and prevents cloning of connected vehicle identities. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM with UID applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 24AA256-I/SN | No factory-programmed UID/EUI; blank upper 1/8th array; otherwise identical electrical and timing specs | Lacks secure device identity; requires external provisioning for MAC generation or serial number assignment | Select only if UID/EUI functionality is unnecessary and cost sensitivity outweighs traceability/security needs |
| AT24CM02-SSHM-T | 2 Mbit capacity; no factory UID; supports 1 MHz I²C; different page size (128 bytes); higher VCC min (1.7V same) | Higher density but no built-in identity; requires software-managed serial number generation and storage | Choose when larger storage is primary requirement and UID can be implemented in MCU firmware or external secure element |
Compared with 24AA256UIDT-I/SN, the 24AA256-I/SN omits factory-programmed identifiers entirely, while AT24CM02-SSHM-T offers greater density but no UID capability-making 24AA256UIDT-I/SN the sole option for hardware-enforced, globally unique, and permanently protected device identity in compact 256 Kbit footprint.
Availability
24AA256UIDT-I/SN is available at Aetrix Electronics and suitable for IoT edge node identity, industrial sensor calibration storage, medical device traceability, and automotive telematics modules requiring stable component supply with guaranteed UID authenticity and long-term lifecycle support.
Supply support for 24AA256UIDT-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, manufacturing, and sales operations.
The 24AA256UIDT-I/SN belongs to Microchip's UID-family of serial EEPROMs, designed specifically to deliver factory-programmed, globally unique identifiers for secure device authentication, regulatory compliance, and anti-counterfeiting in resource-constrained embedded systems.
FAQ
What is the exact memory map location of the 32-bit serial number in the 24AA256UIDT-I/SN?
The 32-bit serial number in the 24AA256UIDT-I/SN is stored at fixed memory addresses 0x7FFC through 0x7FFF. This location resides within the upper 1/8th of the EEPROM array (0x7000–0x7FFF), which is permanently write-protected. The 24AA256UIDT-I/SN also stores a manufacturer code (0x29) at 0x7FFA and device identifier (0x48) at 0x7FFB, both part of the same protected region.
Does the 24AA256UIDT-I/SN support I²C clock stretching or multi-master arbitration?
No, the 24AA256UIDT-I/SN does not support clock stretching or multi-master arbitration. It operates strictly as an I²C slave device with fixed control code 0b1010 and responds only to Start/Stop conditions and address matching. The 24AA256UIDT-I/SN relies on acknowledge polling (by resending the control byte) to detect write completion, rather than stretching SCL.
Can the EUI-48™ and EUI-64™ addresses in the 24AA256UIDT-I/SN be overwritten or modified after programming?
No, the EUI-48™ (at 0x7F7A–0x7F7F) and EUI-64™ (at 0x7FB8–0x7FBF) addresses in the 24AA256UIDT-I/SN are factory-programmed and reside outside the permanently write-protected upper 1/8th region-but they are located in standard EEPROM space and *can* be overwritten by user firmware. However, doing so invalidates IEEE compliance and breaks uniqueness guarantees; Microchip strongly advises against modification.
What is the maximum allowed SDA/SCL bus capacitance for reliable 400 kHz operation of the 24AA256UIDT-I/SN?
For reliable 400 kHz I²C operation, the total bus capacitance (CB) on SDA and SCL lines must not exceed 400 pF, as derived from the AC specification TR ≤ 300 ns (for VCC ≥2.5V) and the RC time constant relationship. The 24AA256UIDT-I/SN's output fall time (TOF) is specified as 10 + 0.1CB ns, and exceeding 400 pF risks violating setup/hold timing margins. Use 2 kΩ pull-ups and minimize trace length to stay within limit.
How does the 24AA256UIDT-I/SN handle page boundary crossing during a page write operation?
The 24AA256UIDT-I/SN enforces strict physical page boundaries (64-byte alignment). If a page write command attempts to cross a boundary-e.g., writing 65 bytes starting at 0x003F-the address counter wraps around to the start of the same page (0x0000), overwriting previously loaded data. The 24AA256UIDT-I/SN does not auto-advance to the next page; software must split writes at 64-byte boundaries to avoid data corruption.
24AA256UIDT-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:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- I2C
- Clock Frequency:
- 400 kHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- 900 ns
- Voltage - Supply:
- 1.7V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
24AA256UIDT-I/SN FAQ
1.How can I place an order for 24AA256UIDT-I/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 24AA256UIDT-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 24AA256UIDT-I/SN reliable?
The price and inventory of 24AA256UIDT-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 24AA256UIDT-I/SN is usually 5 days.
3.What payment methods are accepted for 24AA256UIDT-I/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24AA256UIDT-I/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24AA256UIDT-I/SN?
24AA256UIDT-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24AA256UIDT-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 24AA256UIDT-I/SN?
For technical support, including 24AA256UIDT-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24AA256UIDT-I/SN requirements.
6.How does Aetrix verify that 24AA256UIDT-I/SN is sourced from the original manufacturer or authorized distributors?
All 24AA256UIDT-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 24AA256UIDT-I/SN meets industry standards.
7.What is the process for return or replacement of 24AA256UIDT-I/SN?
All 24AA256UIDT-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 24AA256UIDT-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 24AA256UIDT-I/SN part is unused and in its original packaging.
Return procedure for 24AA256UIDT-I/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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