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Microchip Technology 24CS256T-I/SN

Name: 24CS256T-I/SN
Brand: Microchip Technology
SKU: 24CS256T-I/SN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 24CS256T-I/SN

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: 24CS256T-I/SN.pdf

Description:: IC EEPROM 256KBIT I2C 8SOIC

Quantity:: RFQ Add To RFQ list

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Inventory:2,872

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Product details

Overview

24CS256T-I/SN from Microchip Technology is a 256-Kbit I²C serial EEPROM organized as 32,768 × 8-bit, supporting byte/page writes (up to 64 bytes), self-timed write cycles ≤5 ms, and high-speed I²C up to 3.4 MHz. It features a factory-programmed 128-bit serial number, user-lockable 64-byte ID page, built-in ECC for single-bit error correction, and hardware/software write protection - deployed in automotive infotainment control modules requiring tamper-resistant configuration storage.

For engineers reviewing the 24CS256T-I/SN datasheet, 24CS256T-I/SN pinout, 24CS256T-I/SN application, or 24CS256T-I/SN equivalent, key selection criteria include I²C speed compatibility (100 kHz–3.4 MHz), 1.7V–5.5V supply operation, AEC-Q100 qualification, ECC-enabled data integrity, and dual-zone write protection (hardware WP pin + software-configurable 32-Kbit zones).

Technical Context

The 24CS256T-I/SN implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. Its memory architecture comprises a 256-Kbit main array (0000h–7FFFh) and a dedicated 1-Kbit security register split into read-only 128-bit serial number (0800h–080Fh) and programmable/lockable 64-byte ID page (0840h–087Fh).

Device behavior is modulated via a configurable register enabling legacy hardware write protection or enhanced software-based zone protection across eight independent 32-Kbit blocks. The Configuration register itself can be permanently locked. An on-chip Error Correction State (ECS) latch reports ECC invocation, and the device supports I²C Manufacturer ID commands returning a unique 24-bit identifier.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	256 Kbit (32,768 × 8-bit), organized in 512 pages of 64 bytes each - enables efficient firmware parameter storage with page-level write optimization.
I²C Speed Support	Up to 3.4 MHz (High-Speed mode), plus 1 MHz / 400 kHz / 100 kHz - ensures compatibility with modern microcontrollers and real-time system timing budgets.
Write Cycle Time	≤5 ms (self-timed), no external polling required - simplifies host firmware by eliminating busy-wait loops during nonvolatile updates.
Operating Voltage	1.7 V to 5.5 V - supports direct interfacing with 1.8 V, 3.3 V, and 5 V logic domains without level shifters.
Data Retention	>200 years at 55°C - guarantees long-term reliability in automotive and industrial deployments where field replacement is impractical.
Endurance	1,000,000 erase/write cycles - validated for applications requiring frequent calibration or logging updates over product lifetime.
Temperature Range	Industrial grade: –40°C to +85°C - qualified per AEC-Q100 Grade 2, suitable for under-hood and dashboard electronics.
ESD Protection	>4000 V HBM - enhances robustness against handling and system-level ESD events in manufacturing and field service.

Pinout & Package

24CS256T-I/SN is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with gull-wing leads, RoHS-compliant matte tin finish, and wettable flank geometry for automated optical inspection (AOI) and solder joint reliability verification.

Pin/Terminal	Circuit Role	Design Meaning
A0	Hardware Address Input	LSB of 3-bit device address; hardwired to VSS or VCC to enable up to eight devices on one I²C bus - essential for multi-node sensor or actuator systems.
A1	Hardware Address Input	Middle bit of 3-bit device address; determines unique I²C client address alongside A0 and A2 - prevents bus contention in distributed control architectures.
A2	Hardware Address Input	MSB of 3-bit device address; must be tied to VSS in SOT-23 variants but fully functional in SOIC - enables scalable memory expansion without address conflicts.
VSS	Ground Reference	Primary return path for all internal circuitry and I/O; requires low-impedance connection to system ground plane to maintain noise immunity and ECC accuracy.
SDA	Serial Data Line	Open-drain bidirectional I²C data line; requires external pull-up resistor (330 Ω for 3.4 MHz); changes only during SCL low - defines data transfer timing integrity.
SCL	Serial Clock Line	Input-only I²C clock; synchronizes all read/write operations; slope control minimizes ground bounce during fast transitions - critical for signal integrity at 3.4 MHz.
WP	Write-Protect Control	Active-high hardware lock; when tied to VCC, disables all writes to main array and security register - provides fail-safe protection against accidental firmware corruption.
VCC	Power Supply	1.7–5.5 V operating voltage input; includes internal POR circuit with 100 µs TPUP delay - ensures deterministic initialization after power-on or brownout recovery.

Key Features

Feature	Design Value
128-bit factory serial number	Uniquely identifies each unit across the CS series; eliminates need for external serialization in production test - reduces BOM count and line-side programming time.
64-byte lockable ID page	User-programmable section of security register; once locked, prevents modification of calibration data, cryptographic keys, or device-specific credentials - enforces secure boot chain integrity.
Built-in ECC logic	Corrects single-bit errors within any four-byte read window; ECS latch flags correction events - maintains data validity without host intervention in harsh EMI environments.
Enhanced software write protection	Configurable via register to protect any of eight 32-Kbit zones independently; allows partial memory lockdown while leaving other regions writable - supports modular firmware update schemes.
I²C Manufacturer ID support	Returns fixed 24-bit identifier upon command; enables automatic device enumeration and firmware validation during system startup - prevents misconfiguration in mixed-EEPROM designs.
Low-power standby current	1 µA at 5.5 V (I-temp); enables always-on memory retention in battery-backed systems such as telematics loggers or smart sensors.

Applications

Automotive Body Control Module	Industrial PLC Configuration Storage
Use Scenario: Storing door lock settings, mirror position presets, and seat memory profiles across vehicle lifecycle. IC Role / Device Role / Timing Role: Nonvolatile configuration register providing persistent state retention between ignition cycles and battery disconnects. Use Value: AEC-Q100 qualification and >200-year data retention ensure settings survive 15+ year vehicle service life without degradation or recalibration.	Use Scenario: Holding ladder logic parameters, I/O mapping tables, and calibration coefficients in programmable logic controllers. IC Role / Device Role / Timing Role: Field-updatable memory element accessed via controller's I²C master during commissioning or maintenance. Use Value: 1,000,000 write cycles and ECC support guarantee reliable reprogramming even in high-vibration factory environments with frequent firmware revisions.
Medical Infusion Pump Calibration	Smart Energy Meter Firmware Parameters
Use Scenario: Securing drug delivery rate limits, dose history logs, and sensor calibration offsets in Class II medical devices. IC Role / Device Role / Timing Role: Tamper-resistant storage for safety-critical parameters, leveraging hardware WP pin and lockable ID page. Use Value: Preprogrammed 128-bit serial number enables traceability per FDA UDI requirements; ECC prevents silent data corruption affecting dosage accuracy.	Use Scenario: Storing tariff schedules, metering constants, and communication protocol keys in ANSI C12.22-compliant utility meters. IC Role / Device Role / Timing Role: Secure, long-life memory for regulatory-mandated data with cryptographic key protection. Use Value: Software-configurable zone protection isolates keys from operational parameters - enabling OTA updates without exposing sensitive credentials.

Automotive Body Control Module

Industrial PLC Configuration Storage

Use Scenario: Storing door lock settings, mirror position presets, and seat memory profiles across vehicle lifecycle.

IC Role / Device Role / Timing Role: Nonvolatile configuration register providing persistent state retention between ignition cycles and battery disconnects.

Use Value: AEC-Q100 qualification and >200-year data retention ensure settings survive 15+ year vehicle service life without degradation or recalibration.

Use Scenario: Holding ladder logic parameters, I/O mapping tables, and calibration coefficients in programmable logic controllers.

IC Role / Device Role / Timing Role: Field-updatable memory element accessed via controller's I²C master during commissioning or maintenance.

Use Value: 1,000,000 write cycles and ECC support guarantee reliable reprogramming even in high-vibration factory environments with frequent firmware revisions.

Medical Infusion Pump Calibration

Smart Energy Meter Firmware Parameters

Use Scenario: Securing drug delivery rate limits, dose history logs, and sensor calibration offsets in Class II medical devices.

IC Role / Device Role / Timing Role: Tamper-resistant storage for safety-critical parameters, leveraging hardware WP pin and lockable ID page.

Use Value: Preprogrammed 128-bit serial number enables traceability per FDA UDI requirements; ECC prevents silent data corruption affecting dosage accuracy.

Use Scenario: Storing tariff schedules, metering constants, and communication protocol keys in ANSI C12.22-compliant utility meters.

IC Role / Device Role / Timing Role: Secure, long-life memory for regulatory-mandated data with cryptographic key protection.

Use Value: Software-configurable zone protection isolates keys from operational parameters - enabling OTA updates without exposing sensitive credentials.

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
AT24C256C-SSHL-T	No built-in ECC; no security register; max I²C speed 1 MHz; no AEC-Q100 qualification.	Lacks tamper resistance and automotive reliability; suitable only for cost-sensitive consumer products.	Select only if ECC, serial number, and automotive qualification are unnecessary and 1 MHz I²C suffices.
24AA256-I/SN	No security register; no ECC; no High-Speed mode (max 400 kHz); same pinout and voltage range.	Lower performance and security; used in legacy industrial designs where upgrade path is constrained.	Choose only for drop-in replacement in existing 24AA256 designs where enhanced features are unused.

Compared with AT24C256C-SSHL-T and 24AA256-I/SN, the 24CS256T-I/SN delivers higher reliability through ECC, stronger security via factory serial number and lockable ID page, and faster 3.4 MHz I²C - making it the sole choice for AEC-Q100-compliant, safety-aware, and future-proof embedded systems.

Availability

24CS256T-I/SN is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLCs, and medical infusion pumps requiring stable component supply, long-lifecycle assurance, and certified reliability.

Supply support for 24CS256T-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 microcontrollers, analog components, and memory solutions, serving automotive, industrial, and communications markets with vertically integrated silicon and software.

The 24CS256T-I/SN belongs to Microchip's CS-series serial EEPROM family, engineered specifically for automotive-grade, high-reliability nonvolatile storage with integrated security and error resilience - addressing design needs in safety-critical and long-service-life applications.

FAQ

What is the maximum I²C clock frequency supported by the 24CS256T-I/SN?

The 24CS256T-I/SN supports High-Speed mode up to 3.4 MHz when VCC ≥2.5 V and operating in Industrial temperature range. At lower voltages (1.7 V–2.5 V) or Extended temperature range, maximum clock frequency is 1 MHz. This enables high-throughput configuration loading in real-time systems without compromising timing margins.

Does the 24CS256T-I/SN require external pull-up resistors on SDA and SCL lines?

Yes, the 24CS256T-I/SN requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. Recommended values are 330 Ω for 3.4 MHz operation, 2 kΩ for 1 MHz/400 kHz, and 10 kΩ for 100 kHz - ensuring proper rise times and noise immunity per I²C specification.

How does the built-in ECC in the 24CS256T-I/SN function during read operations?

The 24CS256T-I/SN applies ECC correction automatically during every read operation across any four-byte boundary. If a single-bit error is detected, it is corrected transparently, and the Error Correction State (ECS) latch in the Configuration register is set. Host firmware can poll ECS to log potential memory stress events without interrupting normal operation.

Can the 128-bit serial number in the 24CS256T-I/SN be overwritten or modified?

No, the 128-bit serial number in the 24CS256T-I/SN is factory-programmed and permanently read-only. It resides in the first 16 bytes (0800h–080Fh) of the security register and cannot be altered, erased, or reprogrammed - providing guaranteed uniqueness and traceability for anti-counterfeiting and regulatory compliance.

What happens if the WP pin is left floating on the 24CS256T-I/SN?

The WP pin on the 24CS256T-I/SN must be actively driven to either VSS (enables writes) or VCC (disables writes); leaving it floating violates the Absolute Maximum Ratings and may cause undefined behavior, including intermittent write failures or unintended memory protection. A pull-down resistor to VSS is recommended unless hardware write protection is required.

Is the 24CS256T-I/SN pin-compatible with the 24LC256 across all package types?

The 24CS256T-I/SN is pin-compatible with the 24LC256 in 8-lead SOIC, MSOP, PDIP, TSSOP, and UDFN packages, sharing identical pin functions and layout. However, differences in internal registers, ECC, and security features mean firmware must be updated to leverage new capabilities - it is not a drop-in functional replacement without validation.

24CS256T-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:: 3.4 MHz

Write Cycle Time - Word, Page:: 5ms

Access Time:: 70 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

24CS256T-I/SN FAQ

1.How can I place an order for 24CS256T-I/SN through Aetrix?

Please submit a Request for Quotation (RFQ) for 24CS256T-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 24CS256T-I/SN reliable?

The price and inventory of 24CS256T-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 24CS256T-I/SN is usually 5 days.

3.What payment methods are accepted for 24CS256T-I/SN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24CS256T-I/SN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 24CS256T-I/SN?

24CS256T-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 24CS256T-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 24CS256T-I/SN?

For technical support, including 24CS256T-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24CS256T-I/SN requirements.

6.How does Aetrix verify that 24CS256T-I/SN is sourced from the original manufacturer or authorized distributors?

All 24CS256T-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 24CS256T-I/SN meets industry standards.

7.What is the process for return or replacement of 24CS256T-I/SN?

All 24CS256T-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 24CS256T-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 24CS256T-I/SN part is unused and in its original packaging.

Return procedure for 24CS256T-I/SN:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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