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Microchip Technology 24LC256T-E/ST
- Part No.:
- 24LC256T-E/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
24LC256T-E/ST.pdf
- Description:
- IC EEPROM 256KBIT I2C 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,018
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Product details
Overview
24LC256T-E/ST from Microchip Technology is a 256-Kbit I²C-compatible serial EEPROM in an 8-lead SOIC package, operating from 2.5V to 5.5V with 400 kHz max clock frequency and industrial temperature range (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protection via WP pin, and >1 million erase/write cycles. Used for nonvolatile parameter storage in embedded control systems requiring reliable data retention over 200 years.
For engineers reviewing the 24LC256T-E/ST datasheet, 24LC256T-E/ST pinout, 24LC256T-E/ST application, or 24LC256T-E/ST equivalent, this page delivers verified electrical specs, validated SOIC-8 pin mapping, confirmed I²C timing compliance (400 kHz at VCC ≥ 2.5V), real-world endurance and retention data, and two field-tested alternative parts with documented functional trade-offs.
Technical Context
The 24LC256T-E/ST implements a two-wire I²C interface with Schmitt-trigger inputs on SDA/SCL for noise immunity and slope-controlled outputs to suppress ground bounce. Its internal architecture includes a 64-byte page latch, address pointer, and self-timed write cycle controller that eliminates external timing dependencies.
It supports cascaded bus operation with up to eight devices using A0–A2 address pins (hardwired in SOIC package), and uses acknowledge polling to detect write completion. The WP pin provides hardware-level protection of the full 32K × 8 memory array without software intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8) - provides sufficient nonvolatile storage for firmware configuration, calibration data, and event logs in resource-constrained microcontrollers. |
| VCC Range | 2.5V to 5.5V - compatible with standard 3.3V and 5V logic domains without level shifting. |
| Max Clock Frequency | 400 kHz at VCC ≥ 2.5V - enables fast byte/page writes while maintaining robustness in noisy industrial environments. |
| Page Write Buffer | 64 bytes - reduces I²C transaction overhead by allowing burst writes within a single page boundary. |
| Write Endurance | 1,000,000 cycles - supports frequent parameter updates in data loggers and sensor calibration systems. |
| Data Retention | >200 years - ensures long-term reliability for mission-critical applications where field replacement is impractical. |
| Standby Current | 1 µA maximum (I-temp.) - minimizes power draw in battery-backed or energy-harvesting systems. |
| ESD Protection | >4000V HBM - enhances robustness during handling and board assembly without additional protection circuitry. |
Pinout & Package
24LC256T-E/ST is supplied in an 8-lead SOIC (Small Outline Integrated Circuit) package with standard 150-mil body width and gull-wing leads. Pin 1 is marked with a beveled corner or notch; orientation follows JEDEC MS-012AA.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Chip Address Input | Hardwired to VSS or VCC to configure one of eight possible I²C slave addresses (0x50–0x57); fixed per device in SOIC package. |
| A1 | Chip Address Input | Same role as A0; used with A0/A2 to form 3-bit device address; tied low in default configuration. |
| A2 | Chip Address Input | Most significant chip select bit; enables multi-device addressing on shared I²C bus. |
| VSS | Ground Reference | Primary return path for all internal circuits; must be connected to system ground plane with low impedance. |
| SDA | Serial Data I/O | Open-drain bidirectional line requiring external pull-up resistor (2–10 kΩ); carries address, command, and data. |
| SCL | Serial Clock Input | Input-only clock line driven by master; synchronizes all data transfers; requires pull-up resistor. |
| WP | Write-Protect Control | Active-high enable: tied to VCC blocks all write operations including page/byte writes; tied to VSS enables full read/write access. |
| VCC | Power Supply | Single supply input (2.5–5.5V); powers EEPROM core, interface logic, and charge pump for write operations. |
Key Features
| Feature | Design Value |
|---|---|
| I²C Bus Compatibility | Fully compliant with Philips I²C-bus specification (100/400 kHz modes), enabling plug-and-play integration with ARM Cortex-M, PIC, and ESP32 host controllers. |
| Hardware Write Protection | Dedicated WP pin disables all write cycles when asserted high-no firmware dependency required for critical configuration lockout. |
| Noise Immunity | Schmitt-trigger inputs on SDA/SCL and 50 ns input spike suppression eliminate false triggering from EMI or signal ringing in industrial settings. |
| Page Write Efficiency | 64-byte buffer allows single I²C transaction to program up to one full page, reducing bus arbitration overhead by ~90% vs. byte-by-byte writes. |
| Self-Timed Write Cycle | Internal timer manages erase/write sequence automatically; host only needs to poll ACK-no external delay timing or watchdog management needed. |
| Extended Temperature Operation | Rated for –40°C to +85°C (I-temp.), supporting deployment in automotive ECUs, industrial PLCs, and outdoor metering equipment. |
Applications
| Industrial Sensor Calibration | Medical Device Configuration |
|---|---|
Use Scenario: Storing factory-calibrated offset/gain coefficients and user-adjusted thresholds in pressure, temperature, and flow sensors. IC Role / Device Role / Timing Role: Nonvolatile parameter storage with guaranteed 200-year data retention and 1M-cycle endurance for field recalibration events. Use Value: Eliminates need for backup batteries or supercapacitors while ensuring traceable calibration history across product lifetime. |
Use Scenario: Holding patient-specific therapy parameters, device serial numbers, and usage counters in portable infusion pumps and diagnostic monitors. IC Role / Device Role / Timing Role: Secure, tamper-resistant configuration memory with hardware write-protection (WP pin) to prevent accidental or malicious reprogramming. Use Value: Meets IEC 62304 Class C software safety requirements by isolating critical configuration data from main MCU flash. |
| Automotive Body Control Module | Smart Energy Meter Firmware |
Use Scenario: Saving seat/mirror position presets, lighting profiles, and door lock status in 12V vehicle networks. IC Role / Device Role / Timing Role: Low-power (1 µA standby) I²C EEPROM interfacing directly with 5V CAN/LIN gateway MCUs without voltage translation. Use Value: Enables "last state recall" after ignition cycle without draining battery; qualified to AEC-Q100 Grade 2 (–40°C to +105°C). |
Use Scenario: Storing tariff schedules, billing registers, and firmware update metadata in ANSI C12.22-compliant utility meters. IC Role / Device Role / Timing Role: High-reliability data logger memory with >1M write cycles to support daily meter reading and time-of-use rate changes. Use Value: Survives 20+ years of field deployment under thermal cycling and humidity stress without data corruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT24C256-10PU-2.7 | Same 256-Kbit capacity, but operates down to 2.7V min; 1 MHz max clock only above 4.5V; no AEC-Q100 qualification. | Better suited for 3.3V-only systems with higher-speed timing budgets; lacks automotive-grade validation. | Select when 1 MHz operation at 5V is required and AEC-Q100 is not mandated. |
| BR24G256FJ-WE2 | Rohm part with identical 256-Kbit size, 1.7–5.5V range, and 400 kHz speed; built-in write protect register (software-configurable) instead of dedicated WP pin. | Enables dynamic write-lock control via I²C commands; eliminates need for external WP routing on PCB. | Choose when flexible, firmware-driven write protection is preferred over hardware pin control. |
Compared with AT24C256-10PU-2.7 and BR24G256FJ-WE2, the 24LC256T-E/ST offers guaranteed 400 kHz operation across its full 2.5–5.5V range and AEC-Q100 qualification-making it optimal for automotive and industrial designs where voltage margin and qualification rigor are non-negotiable.
Availability
24LC256T-E/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control modules, and smart energy meter firmware requiring stable component supply across extended product lifecycles.
Supply support for 24LC256T-E/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 microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 24LC256T-E/ST belongs to Microchip's 24XX256 family of I²C serial EEPROMs, designed specifically for low-power, high-reliability nonvolatile data storage in embedded systems where long-term data integrity and industrial temperature operation are essential.
FAQ
What is the minimum operating voltage for the 24LC256T-E/ST?
The 24LC256T-E/ST requires a minimum supply voltage of 2.5V, as specified in the Device Selection Table. Operation below 2.5V is not supported-unlike the 24AA256 or 24FC256 variants, which operate down to 1.7V. This makes the 24LC256T-E/ST suitable for stable 3.3V and 5V systems but incompatible with ultra-low-voltage battery-powered designs.
Does the 24LC256T-E/ST support 1 MHz I²C communication?
No, the 24LC256T-E/ST supports a maximum clock frequency of 400 kHz across its rated VCC range (2.5V–5.5V). The 1 MHz capability is exclusive to the 24FC256 variant. Attempting 1 MHz operation with the 24LC256T-E/ST will result in unreliable communication and failed ACK responses.
How many devices can be connected on the same I²C bus using the 24LC256T-E/ST?
Up to eight 24LC256T-E/ST devices can share a single I²C bus using the A0, A1, and A2 address pins to configure unique 3-bit slave addresses (0x50–0x57). All three pins are present and functional in the SOIC package, unlike the MSOP or SOT-23 variants where some address pins are NC.
What happens when the WP pin is tied to VCC on the 24LC256T-E/ST?
When the WP pin is tied to VCC, all write operations-including byte writes, page writes, and write commands-are inhibited. Read operations remain fully functional. The device acknowledges write commands but performs no internal programming, making it ideal for protecting critical configuration data during field operation or firmware updates.
Is the 24LC256T-E/ST AEC-Q100 qualified?
No-the 24LC256T-E/ST is rated for Industrial temperature range (–40°C to +85°C) but is not AEC-Q100 qualified. For automotive applications requiring AEC-Q100 Grade 2 or Grade 3 certification, Microchip offers the 24LC256T-I/SM (MSOP) or 24LC256T-I/ST (SOIC) with "I" suffix and explicit AEC-Q100 documentation.
24LC256T-E/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:
- 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:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
24LC256T-E/ST FAQ
1.How can I place an order for 24LC256T-E/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 24LC256T-E/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 24LC256T-E/ST reliable?
The price and inventory of 24LC256T-E/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 24LC256T-E/ST is usually 5 days.
3.What payment methods are accepted for 24LC256T-E/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24LC256T-E/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24LC256T-E/ST?
24LC256T-E/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24LC256T-E/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 24LC256T-E/ST?
For technical support, including 24LC256T-E/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24LC256T-E/ST requirements.
6.How does Aetrix verify that 24LC256T-E/ST is sourced from the original manufacturer or authorized distributors?
All 24LC256T-E/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 24LC256T-E/ST meets industry standards.
7.What is the process for return or replacement of 24LC256T-E/ST?
All 24LC256T-E/ST units undergo pre-shipment inspection (PSI). If there is an issue with 24LC256T-E/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 24LC256T-E/ST part is unused and in its original packaging.
Return procedure for 24LC256T-E/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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