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Microchip Technology 24LC256-E/SN
- Part No.:
- 24LC256-E/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
24LC256-E/SN.pdf
- Description:
- IC EEPROM 256KBIT I2C 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:528
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Product details
Overview
24LC256-E/SN from Microchip Technology is a 256-Kbit (32K × 8) I²C-compatible serial EEPROM with hardware write-protection, 64-byte page buffer, and operation from 2.5V to 5.5V. It supports up to eight devices on one bus via A0–A2 address pins, delivers ≤5 ms page write time, and guarantees >1 million erase/write cycles with >200 years data retention. Used in industrial sensor calibration storage and embedded system configuration memory.
For engineers reviewing the 24LC256-E/SN datasheet, 24LC256-E/SN pinout, 24LC256-E/SN application, or 24LC256-E/SN equivalent, key selection criteria include VCC min/max compliance (2.5–5.5V), I²C clock support (up to 400 kHz), WP pin behavior, SOIC-8 package dimensions, and page-write boundary handling in firmware.
Technical Context
The 24LC256-E/SN 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 address pointer enables sequential reads across the full 0000h–7FFFh memory space, while cascading via A0–A2 allows up to eight devices per bus for expanded storage.
Write operations are self-timed and support both byte and page modes (max 64 bytes/page); the WP pin disables writes when pulled high, and acknowledge polling is used to detect write completion. The device uses an on-chip HV generator for EEPROM programming and features factory-programmable options.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8), addressing range 0000h–7FFFh - supports full-system configuration storage without external address latching. |
| VCC Range | 2.5V to 5.5V - compatible with 3.3V and 5V logic systems; not operable below 2.5V. |
| I²C Clock Frequency | Up to 400 kHz - enables fast firmware updates; limited to 100 kHz if VCC < 2.5V (not applicable here). |
| Page Write Buffer | 64 bytes - reduces write transaction count by 64× vs. byte writes; requires firmware alignment to page boundaries (00h–3Fh offsets). |
| Write Endurance | 1,000,000 cycles - sufficient for daily calibration logging over 27+ years at 100 writes/day. |
| Data Retention | 200+ years - ensures long-term reliability in unpowered storage applications like medical device settings. |
| Standby Current | 1 µA max (I-temp) - enables ultra-low-power battery-backed operation in portable instrumentation. |
Pinout & Package
24LC256-E/SN is supplied in an 8-lead SOIC (Small Outline Integrated Circuit) package, 3.90 mm body width, with standard JEDEC MS-012AC footprint and matte tin (Sn) lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Chip Address Input | LSB of 3-bit device address; hardwired to VSS or VCC to select one of eight possible I²C addresses (1010xx0 binary prefix). |
| A1 | Chip Address Input | Middle bit of device address; determines unique I²C client address when multiple 24LC256-E/SN devices share a bus. |
| A2 | Chip Address Input | MSB of device address; enables up to eight independent 24LC256-E/SN units on same I²C bus (address range 0x50–0x57). |
| 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; requires external pull-up resistor (2–10 kΩ depending on speed); carries address, data, and ACK bits. |
| SCL | Serial Clock Input | Master-generated clock signal; synchronizes all I²C transfers; rising edge samples SDA, falling edge drives SDA. |
| WP | Hardware Write-Protect | Active-high input; when tied to VCC, blocks all write commands (byte/page) but permits unlimited reads; sampled at STOP condition. |
| VCC | Power Supply | Single 2.5–5.5V supply; powers EEPROM array, control logic, and I²C interface; decoupling capacitor (0.1 µF) required near pin. |
Key Features
| Feature | Design Value |
|---|---|
| 64-byte page write buffer | Reduces firmware overhead by enabling bulk writes; eliminates need for 64 separate I²C transactions per page update. |
| Schmitt-trigger SDA/SCL inputs | Provides ≥50 mV hysteresis (VHYS = 0.05×VCC) to reject noise spikes on noisy industrial PCBs without external filtering. |
| Self-timed write cycle | Removes requirement for host MCU to manage write timing; internal 5 ms timeout ensures deterministic completion. |
| Hardware write protection (WP) | Prevents accidental firmware corruption during power-up/down or brown-out events without software intervention. |
| Cascadable I²C addressing | Supports up to eight 24LC256-E/SN devices on one bus (0x50–0x57), enabling modular storage expansion in multi-sensor nodes. |
Applications
| Industrial Sensor Calibration Storage | Medical Device Configuration Memory |
|---|---|
|
Use Scenario: Storing temperature/pressure sensor offset/gain coefficients in factory-calibrated modules operating in -40°C to +85°C environments. IC Role / Device Role / Timing Role: Nonvolatile configuration register holding calibration constants accessed at boot and updated only during recalibration. Use Value: Eliminates need for external microcontroller EEPROM management; 200-year retention ensures lifetime calibration integrity without field recalibration. |
Use Scenario: Holding patient-specific therapy parameters (e.g., infusion rate limits, alarm thresholds) in battery-powered portable infusion pumps. IC Role / Device Role / Timing Role: Secure, low-power persistent memory retaining critical safety settings across power cycles and battery swaps. Use Value: 1 µA standby current extends battery life; hardware WP prevents runtime parameter corruption during ESD events or voltage transients. |
| Automotive Body Control Module (BCM) Settings | Smart Energy Meter Firmware Patch Storage |
|
Use Scenario: Saving user preferences (mirror position, seat memory) and diagnostic fault logs in AEC-Q100-compliant BCMs. IC Role / Device Role / Timing Role: I²C slave storing infrequently written but mission-critical state data accessible via CAN-to-I²C gateway. Use Value: AEC-Q100 qualification ensures reliability under automotive thermal cycling; 1M endurance supports 10+ years of daily usage. |
Use Scenario: Storing signed firmware patches and cryptographic keys for secure over-the-air (OTA) updates in utility-grade smart meters. IC Role / Device Role / Timing Role: Tamper-resistant nonvolatile storage for immutable update payloads verified before execution. Use Value: Hardware WP prevents unauthorized patch injection; 400 kHz I²C speed enables rapid OTA payload loading during maintenance windows. |
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); identical pinout, timing, and memory map. | Preferred for 1.8V/2.5V systems where 24LC256-E/SN cannot operate. | Select 24AA256-I/SN only if supply voltage drops below 2.5V; otherwise, 24LC256-E/SN offers tighter VCC spec and same cost. |
| AT24C256-10PU-2.7 | Same 256-Kbit capacity, SOIC-8, 2.7–5.5V; slower max clock (1 MHz only at VCC ≥ 2.7V; 400 kHz typical). | Requires revalidation of I²C timing margins; no AEC-Q100 qualification. | Use AT24C256-10PU-2.7 only if sourcing constraints require Atmel/Dialog parts; verify WP behavior and page boundary handling match. |
Compared with 24AA256-I/SN and AT24C256-10PU-2.7, the 24LC256-E/SN provides optimal balance of industrial temperature rating, strict 2.5V minimum VCC compliance, and guaranteed 400 kHz operation - making it ideal for legacy 3.3V/5V designs requiring drop-in reliability without voltage headroom trade-offs.
Availability
24LC256-E/SN is available at Aetrix Electronics and suitable for industrial sensor calibration storage, medical device configuration memory, and automotive body control module settings requiring stable component supply and long-term lifecycle support.
Supply support for 24LC256-E/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 design and manufacturing operations.
The 24LC256-E/SN belongs to Microchip's 24XX256 family of I²C serial EEPROMs, designed specifically for low-power, high-reliability nonvolatile storage in industrial, medical, and automotive applications where data integrity and long-term retention are critical.
FAQ
What is the minimum operating voltage for the 24LC256-E/SN?
The 24LC256-E/SN requires a minimum VCC of 2.5V and operates up to 5.5V. Unlike the 24AA256 variant, it is not rated for 1.7V operation. Below 2.5V, the device will not respond to I²C commands or execute writes, and read data may be invalid. Always verify system rail stability within this window before deployment.
How does the WP pin function on the 24LC256-E/SN?
The WP (Write-Protect) pin on the 24LC256-E/SN is sampled at the STOP condition of each write command. When pulled high to VCC, it disables all byte and page writes while permitting unlimited reads. Toggling WP during a write cycle has no effect - protection is latched only at STOP. This ensures robustness against transient glitches.
Can the 24LC256-E/SN be used in AEC-Q100 qualified automotive applications?
Yes - the 24LC256-E/SN is explicitly AEC-Q100 qualified for automotive use. The "E" suffix denotes Extended temperature grade (-40°C to +125°C), and Microchip certifies this part for use in body electronics, infotainment, and ADAS subsystems where EEPROM reliability under thermal stress is mandatory.
What is the maximum I²C clock frequency supported by the 24LC256-E/SN?
The 24LC256-E/SN supports up to 400 kHz I²C clock frequency when VCC is 2.5V or higher. It does not support the 1 MHz mode found in the 24FC256 variant. At 400 kHz, setup/hold times (e.g., TSU:DAT = 100 ns) and rise/fall times (TR/TF ≤ 300 ns) must be met using appropriate pull-up resistors and bus capacitance control.
How many devices can be connected to the same I²C bus using the 24LC256-E/SN?
Up to eight 24LC256-E/SN devices can share one I²C bus using the A0, A1, and A2 address pins to configure unique 3-bit chip addresses (0x50–0x57). Each pin must be hardwired to VSS or VCC - floating connections are undefined and will cause bus contention or unpredictable addressing.
24LC256-E/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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-SOIC
24LC256-E/SN FAQ
1.How can I place an order for 24LC256-E/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 24LC256-E/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 24LC256-E/SN reliable?
The price and inventory of 24LC256-E/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 24LC256-E/SN is usually 5 days.
3.What payment methods are accepted for 24LC256-E/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24LC256-E/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24LC256-E/SN?
24LC256-E/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24LC256-E/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 24LC256-E/SN?
For technical support, including 24LC256-E/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24LC256-E/SN requirements.
6.How does Aetrix verify that 24LC256-E/SN is sourced from the original manufacturer or authorized distributors?
All 24LC256-E/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 24LC256-E/SN meets industry standards.
7.What is the process for return or replacement of 24LC256-E/SN?
All 24LC256-E/SN units undergo pre-shipment inspection (PSI). If there is an issue with 24LC256-E/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 24LC256-E/SN part is unused and in its original packaging.
Return procedure for 24LC256-E/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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