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Microchip Technology 24LC256T-E/SM
- Part No.:
- 24LC256T-E/SM
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
24LC256T-E/SM.pdf
- Description:
- IC EEPROM 256KBIT I2C 8SOIJ
- Quantity:
- Payment:
- Shipping:
Inventory:1,922
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Product details
Overview
24LC256T-E/SM from Microchip Technology is a 256-Kbit I²C serial EEPROM in an 8-lead SOIJ package, operating from 2.5V to 5.5V with 400 kHz maximum 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 Schmitt-trigger inputs for noise immunity. Used in embedded systems for parameter storage, calibration data retention, and firmware configuration.
For engineers reviewing the 24LC256T-E/SM datasheet, 24LC256T-E/SM pinout, 24LC256T-E/SM application, or 24LC256T-E/SM equivalent, this page delivers verified electrical specs, validated SOIJ package mapping, confirmed I²C timing compliance (400 kHz @ VCC ≥ 2.5V), endurance (1M cycles), and real-world use cases in power management and sensor node design.
Technical Context
The 24LC256T-E/SM implements a two-wire I²C-compatible interface with fixed 7-bit client address prefix '1010' and user-configurable A2/A1/A0 bits for up to eight devices on one bus. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and memory control logic supporting byte and page writes with self-timed erase/write cycles.
It uses open-drain SDA/SCL with external pull-ups, supports Start/Stop condition detection, and incorporates Schmitt-trigger inputs (VHYS = 0.05×VCC) and output slope control to suppress ground bounce. Write protection is hardware-enforced via the WP pin, sampled at Stop bit assertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8), enabling storage of 32,768 bytes of nonvolatile configuration or calibration data |
| VCC Range | 2.5V to 5.5V - compatible with standard 3.3V and 5V microcontroller I/O domains without level shifting |
| Max Clock Frequency | 400 kHz at VCC ≥ 2.5V - supports high-speed I²C communication while maintaining timing margin per Table 1-2 |
| Page Write Buffer | 64 bytes - reduces write transaction count by up to 64× vs. byte-write mode, improving system-level throughput |
| Endurance | 1,000,000 erase/write cycles - ensures reliable operation over 10+ years in field-deployed industrial logging applications |
| Data Retention | 200 years at +85°C - guarantees long-term integrity of stored calibration coefficients and security keys |
| Write Current | 3 mA max - limits peak supply demand during write cycles, easing power budgeting in battery-powered nodes |
| Standby Current | 1 µA max (I-temp.) - enables ultra-low-power sleep modes in always-on sensor interfaces |
Pinout & Package
24LC256T-E/SM is supplied in an 8-lead SOIJ (Small Outline J-bend) package, 5.28 mm wide, with gull-wing leads and JEDEC-standard pinout. Pin 1 is marked by notch or bevel; lead finish is matte tin (Sn).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Chip Address Input | User-configurable LSB of 3-bit device address; hardwired to VSS or VCC to select one of eight possible I²C addresses on shared bus |
| A1 | Chip Address Input | Middle bit of device address; determines unique I²C client address when multiple 24LC256T-E/SM devices share SDA/SCL lines |
| A2 | Chip Address Input | MSB of device address; enables cascading up to eight units for 2-Mbit aggregate storage space |
| VSS | Ground Reference | Primary return path for all internal circuitry; must be low-impedance connection to system GND plane |
| SDA | Serial Data I/O | Open-drain bidirectional bus line requiring external pull-up (2 kΩ typical for 400 kHz); carries address, command, and data |
| SCL | Serial Clock Input | Master-generated clock synchronizing all I²C transfers; rising edge samples SDA, falling edge allows SDA change |
| WP | Write-Protect Control | Hardware lock: tied to VCC disables all writes (read-only mode); tied to VSS enables full read/write access |
| VCC | Power Supply | Single 2.5–5.5V supply powering EEPROM array, logic, and interface; decoupling capacitor (0.1 µF) required near pin |
Key Features
| Feature | Design Value |
|---|---|
| Schmitt-trigger inputs (SDA/SCL) | Input hysteresis ≥0.05×VCC eliminates false triggering from EMI or slow-rising signals in noisy industrial environments |
| Output slope control | Controlled SDA fall time (≤300 ns) prevents ground bounce that could corrupt adjacent digital signals on shared PCB planes |
| Page write capability | 64-byte buffer allows single I²C transaction to store a full configuration block, reducing host CPU overhead and bus arbitration latency |
| Hardware write-protection | WP pin directly gates internal write logic - no software vulnerability; protects critical firmware parameters during power-up or reset |
| I²C bus compatibility | Fully compliant with standard-mode (100 kHz) and fast-mode (400 kHz) I²C specifications, including ACK polling and repeated START support |
| ESD robustness | >4000V HBM rating ensures reliability during handling and board assembly without special ESD precautions |
Applications
| Industrial Sensor Calibration | Smart Meter Parameter Storage |
|---|---|
|
Use Scenario: Storing factory-calibrated sensor gain/offset coefficients and temperature compensation tables in environmental monitoring nodes. IC Role / Device Role / Timing Role: Nonvolatile configuration register holding persistent calibration data accessed at power-up by MCU before sensor initialization. Use Value: Enables field-replaceable sensors with zero manual recalibration; leverages 200-year data retention to avoid drift-related maintenance over product lifetime. |
Use Scenario: Recording tariff schedules, billing history, and tamper-event logs in utility smart meters deployed for >15 years. IC Role / Device Role / Timing Role: Secure, write-protected data logger storing time-stamped usage records with WP pin permanently tied to VCC. Use Value: Guarantees audit-trail integrity against accidental or malicious overwrite; 1M-cycle endurance supports daily log updates across full service life. |
| Power Supply Configuration | Medical Device Settings Backup |
|
Use Scenario: Saving user-adjusted voltage/current limits and protection thresholds in programmable DC power supplies. IC Role / Device Role / Timing Role: System configuration vault accessed via I²C during boot and runtime; updated only on explicit user command. Use Value: Eliminates need for external NVRAM or battery-backed SRAM; 2.5V min VCC allows direct interface with 3.3V supply rails. |
Use Scenario: Preserving patient-specific therapy parameters (e.g., infusion rate, alarm thresholds) across power cycles in portable infusion pumps. IC Role / Device Role / Timing Role: Fail-safe settings repository with hardware write-lock activated during therapy delivery to prevent corruption. Use Value: Meets IEC 62304 safety requirements for data integrity; 1 µA standby current extends battery life between recharges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 24AA256-I/SN | Wider VCC range (1.7–5.5V); same 400 kHz speed but supports 100 kHz down to 1.7V; identical SOIC-8 package | Better suited for 1.8V/2.5V systems; not qualified for automotive AEC-Q100 like 24LC256 variants | Select when operating below 2.5V or needing extended low-voltage functionality; verify I²C timing margins at target VCC |
| AT24C256-10PU-2.7 | Same 256-Kbit capacity and SOIC-8 footprint; 1 MHz max clock at 2.7–5.5V; 1 µA standby current; different write cycle time (10 ms vs. 5 ms) | Higher speed option for 3.3V systems; lacks Schmitt-trigger inputs and slope control, requiring cleaner signal integrity | Choose for faster write throughput where board layout ensures low-noise I²C routing; confirm WP pin behavior matches system lock policy |
Compared with 24LC256T-E/SM, the 24AA256-I/SN offers broader voltage flexibility but no automotive qualification, while the AT24C256-10PU-2.7 provides higher clock speed at the cost of reduced noise immunity and longer write time - both require validation of WP logic and timing compliance in the target application.
Availability
24LC256T-E/SM is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and smart energy metering requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for 24LC256T-E/SM 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 design and manufacturing operations.
The 24LC256 belongs to Microchip's legacy serial EEPROM product line, designed specifically for low-power, high-reliability nonvolatile data storage in resource-constrained embedded systems across industrial, medical, and communications markets.
FAQ
What is the operating voltage range for the 24LC256T-E/SM?
The 24LC256T-E/SM operates from 2.5V to 5.5V. This range ensures compatibility with common 3.3V and 5V logic families without level translation. Operation below 2.5V is not supported - unlike the 24AA256 variant, which functions down to 1.7V. The specified VCC minimum guarantees correct internal charge pump operation and EEPROM write margin.
Does the 24LC256T-E/SM support 1 MHz I²C communication?
No, the 24LC256T-E/SM supports up to 400 kHz I²C clock frequency at VCC ≥ 2.5V. The 1 MHz capability is exclusive to the 24FC256 variant. Attempting 1 MHz operation on the 24LC256T-E/SM will violate AC timing parameters (e.g., THIGH, TLOW), resulting in unreliable ACKs or data corruption. Always consult Table 1-2 in DS20001203Y for validated timing.
How does the WP pin function on the 24LC256T-E/SM?
The WP (Write-Protect) pin on the 24LC256T-E/SM is a hardware enable/disable control for write operations. When tied to VCC, all write commands (byte and page) are inhibited - reads remain fully functional. When tied to VSS, full read/write access is granted. The pin state is sampled at the Stop bit of each write command, making it effective even during active bus transactions.
What package type is used for the 24LC256T-E/SM?
The 24LC256T-E/SM uses an 8-lead SOIJ (Small Outline J-bend) package, 5.28 mm wide, with gull-wing leads and standard JEDEC pinout. The 'SM' suffix in the part number explicitly denotes SOIJ. This package offers robust mechanical mounting and thermal performance suitable for industrial reflow profiles, distinct from SOIC, TSSOP, or MSOP variants.
Can multiple 24LC256T-E/SM devices share the same I²C bus?
Yes, up to eight 24LC256T-E/SM devices can operate on a single I²C bus using the A2, A1, and A0 address pins to configure unique 3-bit chip addresses. Each device must have a distinct combination of these pins tied to VSS or VCC. The SOIJ package supports full 3-bit addressing - unlike the MSOP variant, where A0 and A1 are NC.
24LC256T-E/SM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.209", 5.30mm 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-SOIJ
24LC256T-E/SM FAQ
1.How can I place an order for 24LC256T-E/SM through Aetrix?
Please submit a Request for Quotation (RFQ) for 24LC256T-E/SM 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/SM reliable?
The price and inventory of 24LC256T-E/SM 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/SM is usually 5 days.
3.What payment methods are accepted for 24LC256T-E/SM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24LC256T-E/SM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24LC256T-E/SM?
24LC256T-E/SM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24LC256T-E/SM 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/SM?
For technical support, including 24LC256T-E/SM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24LC256T-E/SM requirements.
6.How does Aetrix verify that 24LC256T-E/SM is sourced from the original manufacturer or authorized distributors?
All 24LC256T-E/SM 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/SM meets industry standards.
7.What is the process for return or replacement of 24LC256T-E/SM?
All 24LC256T-E/SM units undergo pre-shipment inspection (PSI). If there is an issue with 24LC256T-E/SM, 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/SM part is unused and in its original packaging.
Return procedure for 24LC256T-E/SM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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