24AA256UIDT-I/SN - 256Kb I2C EEPROM with EUI-48/64 | Microchip
MPN： 24AA256UIDT-I/SN ✓ 啟用中24AA256UIDT-I/SN 概覽
A serial EEPROM (Electrically Erasable Programmable Read-Only Memory) is a non-volatile memory hierarchy member that retains data after power removal, sits below Flash in density, and offers byte-level endurance over millions of write cycles. Within the Microchip 24XX family, the 24AA256UID occupies the upper-density 256 Kbit tier with the unique addition of pre-burned MAC/unique-ID fields, eliminating the need for host firmware to provision IEEE addresses during manufacturing.
Key features include 64-byte page write capability, hardware write-protect pin support via the WC input, low standby current of typically 1 mA maximum, and read current of 1 mA typical at 5.5V. Endurance is rated at 1 million erase/write cycles per byte with data retention greater than 200 years. The device supports a 128-byte write page in firmware-emulation mode and operates across the industrial temperature range of -40C to +85C. I2C addressing is hardwired across the A0, A1, A2 pins, allowing up to eight devices on a single bus.
The 24AA256UIDT-I/SN uses a CMOS floating-gate process with on-chip charge pump for byte/page write operations, and integrates proprietary EUI-48 and EUI-64 node address registers at factory-programmed fixed locations. The unique ID register holds a 32-bit serial number that, when combined with the EUI-64 value, provides a complete IEEE 802-compliant node identity without external provisioning.
Typical applications include industrial sensor nodes, IoT endpoint devices that require a globally unique MAC address for network registration, IPv6/6LoWPAN nodes, asset tracking tags, building automation modules, and medical device identification. The combination of MAC address pre-programming and small SOIC footprint makes it ideal for compact, cost-sensitive connected products.
When designing with this part, ensure the I2C bus pull-ups are sized for the 400 kHz clock rate with the maximum bus capacitance, and verify that the host microcontroller's I2C controller supports both standard 100 kHz and Fast Mode 400 kHz operation. Always check the read/write protect logic before enabling multi-master bus arbitration.
This page consolidates distributor stock and pricing, lists Microchip same-family drop-in alternatives, and adds practical design notes that complement the manufacturer datasheet for the EUI-48/EUI-64 feature set.
直接替換替代品，適用於 24AA256UIDT-I/SN — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： 24AA256UIDT-I/SN （相同外形與佔位） — 差異在於 Package, Memory Size, Memory Type, Endurance, Memory Organization.
24AA256UID-I/SN
✅ 直接替換聯絡詢價
查看資料表 →24AA256-I/SN
✅ 直接替換聯絡詢價
查看資料表 →24AA256T-I/SN
✅ 直接替換📋 參考替代品（不在目錄中）
24AA256T-I/ST
✅ 直接替換📋 參考替代品（不在目錄中）
24AA256UID-I/ST
✅ 直接替換📋 參考替代品（不在目錄中）
M24256-DFDW6TP
✅ 直接替換📋 參考替代品（不在目錄中）
24AA256UIDT-I/SN 規格
| 記憶體類型 | Non-Volatile EEPROM (Serial I2C) |
| 記憶體容量 | 256 Kbit (32K x 8) |
| 介面 | I2C (2-Wire Serial) |
| 最大時脈頻率 | 400 kHz (Fast Mode) |
| Access Time | 900 ns |
| Supply Voltage Range | 1.7 V to 5.5 V |
| Page Write Size | 64 bytes |
| Write Cycle Time (Byte) | 5 ms max (typical) |
| Endurance | 1,000,000 erase/write cycles per byte |
| Data Retention | >200 years |
| Standby Current | 1 uA typical |
| Operating Current (Read) | 1 mA typical at 400 kHz |
| Pre-Programmed Identity | EUI-48 + EUI-64 IEEE MAC address + 32-bit Unique ID |
| 工作溫度範圍 | -40C to +85C (Industrial) |
| 封裝 | 8-pin SOIC (SN) 3.90 mm |
| 安裝類型 | Surface Mount |
| MSL 等級 | 1 (unlimited floor life) |
| RoHS 狀態 | Compliant |
| Lead-Free / Halogen-Free | Yes / Yes |
| Tape & Reel | Yes ("T" suffix) |
24AA256UIDT-I/SN 腳位配置
| 腳位 1 | A0 — I2C slave address bit 0 (tie to VCC or GND) |
| 腳位 2 | A1 — I2C slave address bit 1 (tie to VCC or GND) |
| 腳位 3 | A2 — I2C slave address bit 2 (tie to VCC or GND) |
| 腳位 4 | VSS — Ground reference |
| 腳位 5 | SDA — I2C serial data (open-drain, requires pull-up) |
| 腳位 6 | SCL — I2C serial clock (open-drain, requires pull-up) |
| 腳位 7 | WP — Write-protect input (tie low for write enable) |
| 腳位 8 | VCC — Positive supply voltage (1.7V to 5.5V) |
典型應用
24AA256UIDT-I/SN 適用於 7 應用s: IoT Endpoint Node with Pre-Provisioned MAC, Industrial Sensor Identification Module, Asset Tracking Tag / Inventory Module, Building Automation Node Identity Storage, Medical Device Identification, Compact Wearable / Fitness Tracker, Networked Sensor / IPv6 Node.
IoT Endpoint Node with Pre-Provisioned MAC
The 24AA256UIDT-I/SN's factory-pre-programmed EUI-48 and EUI-64 IEEE MAC addresses remove the need for host-side provisioning in Thread, Zigbee, BLE, and 6LoWPAN nodes. At first boot the host reads the EUI-64 register at fixed address and uses it as the device's globally unique identity for IEEE 802.15.4 network association. The 1.7-5.5V supply covers coin-cell and Li-ion rails; 1 uA standby current suits sleep-mode operation across multi-year battery deployments. The 8-pin SOIC footprint is compatible with hand-soldered prototype boards.
推薦
Industrial Sensor Identification Module
The 24AA256UIDT-I/SN stores 256 Kbit of calibration data and 32-bit serial number for industrial sensors where each unit must be uniquely traceable for quality control. The 1 million write-cycle endurance handles repeated in-field recalibration writes; the 200-year data retention ensures sensor identity survives long deployment cycles. The I2C interface integrates with any industrial MCU, and the -40C to +85C industrial temperature rating supports outdoor or factory-floor installations. Host firmware can serialize events using the unique ID without external MAC ID chips.
推薦
Asset Tracking Tag / Inventory Module
The 24AA256UIDT-I/SN's globally unique 32-bit serial number and EUI-64 identity enable unambiguous identification of every tagged asset without host-side ID generation. The 256 Kbit capacity stores additional logistics metadata such as shipping history, calibration certificates, or maintenance logs. The wide 1.7-5.5V range supports both coin-cell RFID tags and 3.3V active BLE beacons. The SOIC package is suitable for hand-soldered prototype tags and high-volume SMT reel production.
推薦
Building Automation Node Identity Storage
Building automation devices such as BACnet, KNX, and Modbus nodes require a unique MAC or device ID for network commissioning. The 24AA256UIDT-I/SN provides this identity pre-programmed at the factory, allowing the BACnet MSTP or KNX stack to read the EUI-48 on first power-up and bind it to the building management system. The 1 uA standby current suits permanently-powered wall controllers, while the 1.7V minimum supply permits battery-backed wireless sensor nodes. The 256 Kbit storage also holds configuration profiles per zone.
推薦
Medical Device Identification
The 24AA256UIDT-I/SN is used in regulated medical devices where each unit must carry a unique serial number for FDA UDI compliance and post-market traceability. The factory-programmed EUI-64 and 32-bit unique ID, combined with 256 Kbit of user storage, allow the device to record device-history logs, calibration timestamps, and patient-use counters in a single non-volatile IC. The 200-year data retention ensures records survive the full equipment lifecycle. The SOIC-8 package suits both hand-assembled clinical instruments and SMT production lines.
推薦
Compact Wearable / Fitness Tracker
Wearables and fitness trackers require a globally unique MAC for Bluetooth pairing and firmware asset management. The 24AA256UIDT-I/SN's EUI-48/EUI-64 registers feed the BLE stack on first boot, eliminating host-side provisioning and saving firmware flash space. The 1.7V minimum supply pairs directly with single-cell Li-ion or Li-poly batteries; 1 uA standby current preserves battery life in sleep mode. The 8-pin SOIC is small enough for wristband enclosures; 64-byte page writes support fast configuration block storage.
推薦
Networked Sensor / IPv6 Node
IPv6-connected sensors over 6LoWPAN, Thread, or LoRaWAN require a unique 64-bit interface identifier for the IPv6 address. The 24AA256UIDT-I/SN's pre-programmed EUI-64 maps directly to the IPv6 IID, allowing the network stack to assemble the full IPv6 address without external provisioning. The 256 Kbit user area stores per-device security keys, calibration data, and runtime logs. The 400 kHz Fast Mode I2C clock supports fast multi-byte page reads for boot-time identity retrieval. Industrial temperature range suits outdoor deployments.
推薦
推薦產品摘要
工程參考資料，適用於 24AA256UIDT-I/SN — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | 24AA256UID-I/SN | 24AA256-I/SN | 24AA256T-I/SN | 24AA256T-I/ST | 24AA256UID-I/ST | M24256-DFDW6TP |
|---|---|---|---|---|---|---|---|
| Package | 8-pin SOIC (SN) | 8-pin SOIC (SN) - same | 8-pin SOIC (SN) - same | 8-pin SOIC (SN) - same | 8-pin TSSOP (ST) | 8-pin TSSOP (ST) | 8-pin TSSOP (DW8) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | STMicroelectronics |
| Density | 256 Kbit (32K x 8) | 256 Kbit | 256 Kbit | 256 Kbit | 256 Kbit | 256 Kbit | 256 Kbit |
| Factory EUI-48/EUI-64 + 32-bit UID | Yes | Yes | No | No | No | Yes | No |
| I2C Clock | 400 kHz | 400 kHz | 400 kHz | 400 kHz | 400 kHz | 400 kHz | 400 kHz |
| Supply Voltage Range | 1.7V to 5.5V | 1.7V to 5.5V | 1.7V to 5.5V | 1.7V to 5.5V | 1.7V to 5.5V | 1.7V to 5.5V | 1.8V to 5.5V |
| Page Write Size | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes |
| Endurance | 1,000,000 cycles/byte | 1,000,000 cycles/byte | 1,000,000 cycles/byte | 1,000,000 cycles/byte | 1,000,000 cycles/byte | 1,000,000 cycles/byte | 1,000,000 cycles/byte |
| Industrial Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
主要差異化特點
- Factory-pre-programmed EUI-48/EUI-64 + 32-bit unique ID eliminates host-side MAC provisioning (對比24AA256-I/SN)
- Same die, lower-cost standard variant available for non-identity designs (對比24AA256T-I/SN)
- Cross-brand I2C EEPROM exists but lacks identity registers (對比M24256-DFDW6TP)
設計說明
Place the 24AA256UIDT-I/SN within 50 mm of the host MCU's I2C pins and route SDA/SCL as a differential pair with ground reference. Per Microchip I2C bus design notes, total bus capacitance must stay below 400 pF for reliable 400 kHz Fast Mode operation. Calculate pull-up resistor value as R_pullup = (Vcc - 0.4V) / (3 mA sink), then verify timing with an oscilloscope on a long-bus prototype. Keep the WP pin either directly driven or tied to GND through a 10 kohm resistor to prevent floating-write-protect glitches.
The 24AA256UIDT-I/SN draws up to 1 mA during a 5 ms page write cycle. Ensure the upstream LDO or DC-DC converter can supply this peak without VCC droop below 1.7V, or write operations will fail silently with NACK. Estimated: a 1.7V LDO rated 50 mA with a 1 uF input cap typically provides clean 5 ms write pulses, but adding a 4.7 uF ceramic bulk cap on the EEPROM VCC pin is recommended to absorb transient inrush. In sleep mode the part draws only 1 uA, so a coin-cell can power the system for years.
Three common pitfalls with the 24AA256UIDT-I/SN: (1) The A0/A1/A2 address pins must NOT float - tie them to VCC or GND through a 10 kohm resistor or directly, otherwise the I2C slave address becomes unpredictable. (2) The write-protect WP must be LOW to enable writes; tying WP high permanently disables all write operations after the initial factory programming. (3) The EUI-48/EUI-64 registers are READ-ONLY - host attempts to write them will fail with NACK; design firmware to read them once at boot and cache in RAM, not retry writes.
For 400 kHz Fast Mode operation, keep SDA/SCL traces short (<100 mm) and avoid routing near high-current switching nodes. Place 4.7 kohm pull-ups to VCC on both lines; smaller pull-ups (2.2 kohm) may be needed for very long buses. The 24AA256UIDT-I/SN inputs are Schmidt-triggered, so they tolerate moderate noise on SDA/SCL, but sub-100 ns glitches still risk false clocking. Add a 100 nF decoupling cap adjacent to VCC pin and a 10 nF cap on WP if it is routed far from the host.
合規資訊
RoHS and REACH compliant per Microchip product page; lead-free and halogen-free per Microchip environmental certification. Not AEC-Q100 qualified - this part targets commercial/industrial IoT and consumer applications rather than automotive. For automotive-grade EEPROM, select the 24AA256-I/SN automotive variants in the Microchip AEC-Q100 catalog.
