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Microchip Technology 24CS256T-I/CS0668
- Part No.:
- 24CS256T-I/CS0668
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- -
- Datasheet:
-
24CS256T-I/CS0668.pdf
- Description:
- IC EEPROM 256KBIT I2C
- Quantity:
- Payment:
- Shipping:
Inventory:4,532
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Product details
Overview
24CS256T-I/CS0668 from Microchip Technology is a 256-Kbit I²C serial EEPROM organized as 32,768 × 8-bit, supporting high-speed mode up to 3.4 MHz, 1.7V–5.5V operation, and built-in ECC for single-bit error correction. It integrates a factory-programmed 128-bit unique serial number and user-lockable 64-byte ID page, used in automotive infotainment boot configuration and industrial sensor calibration storage.
For engineers reviewing the 24CS256T-I/CS0668 datasheet, 24CS256T-I/CS0668 pinout, 24CS256T-I/CS0668 application, or 24CS256T-I/CS0668 equivalent, key selection criteria include I²C high-speed timing compliance, hardware/software write protection flexibility, ECC-enabled data integrity, and AEC-Q100 qualification for automotive deployment.
Technical Context
The 24CS256T-I/CS0668 implements a two-wire I²C interface with Schmitt-trigger inputs, slope-controlled outputs, and configurable address pins (A0–A2) enabling up to eight devices on one bus. Its memory architecture comprises a 256-Kbit main array and a separate 1-Kbit security register split into read-only serial number (0800h–080Fh) and programmable lockable ID page (0840h–087Fh).
It features dual write protection: hardware-based via WP pin and software-configurable per-zone protection using an 8-bit Configuration register that can be permanently locked. The device supports three distinct I²C address regions-main EEPROM, Security register, and Manufacturer ID-with dedicated access protocols and word address encoding rules.
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 bulk writes without crossing page boundaries. |
| I²C Speed Mode | Up to 3.4 MHz High-Speed mode (2.5V–5.5V, Industrial temp) - reduces firmware update time by >3× vs. standard 400 kHz mode. |
| Write Cycle Time | ≤5 ms max self-timed byte/page write - eliminates external timing control; device signals completion via ACK/NACK behavior. |
| Voltage Range | 1.7V to 5.5V supply - interoperates with 1.8V logic systems and legacy 5V microcontrollers without level shifters. |
| Data Retention | >200 years at 55°C - ensures long-term reliability in sealed automotive modules with no field recalibration needed. |
| Endurance | 1,000,000 erase/write cycles - supports frequent logging in industrial PLCs or OTA update staging buffers. |
| ECC Capability | Corrects up to one bit error per 4-byte read - prevents silent corruption in safety-critical configuration data without host-side overhead. |
Pinout & Package
24CS256T-I/CS0668 is packaged in an 8-lead UDFN (2 mm × 3 mm, wettable flank), optimized for automated optical inspection and high-density PCB layouts. Pin mapping is identical across all 8-lead packages (SOIC, TSSOP, MSOP, VDFN) per Microchip's standardized pinout convention.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A2 | Hardware Device Address Inputs | Three binary inputs selecting one of eight possible I²C addresses (1010xxx); must be hardwired to VSS or VCC - no floating states permitted. |
| SDA | Serial Data Bidirectional Line | Open-drain I²C data line requiring external pull-up; supports multi-master arbitration and clock stretching during internal write cycles. |
| SCL | Serial Clock Input | Asynchronous clock input synchronized internally; rise/fall times constrained to ≤1000 ns / ≤300 ns to meet 3.4 MHz HS-mode timing. |
| WP | Hardware Write-Protect Control | Active-high pin disabling all writes to main array and security register when driven to VCC - independent of software protection state. |
| VSS | Ground Reference | Primary return path for all internal circuitry; must be low-impedance connection to minimize noise coupling into SDA/SCL. |
| VCC | Power Supply Input | 1.7V–5.5V tolerant supply; includes internal POR circuit with 1.5 V threshold and 100 µs TPUP delay before command acceptance. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-Programmed Serial Number | Globally unique 128-bit read-only identifier (0800h–080Fh) - eliminates manufacturing serialization steps and enables secure device binding in firmware. |
| Lockable User ID Page | 64-byte programmable section (0840h–087Fh) permanently lockable via software sequence - stores cryptographic keys or calibration coefficients with irreversible write protection. |
| Enhanced Software Write Protection | Configuration register enables zone-level protection of eight independent 32-Kbit blocks - allows partial updates while safeguarding critical boot parameters. |
| I²C Manufacturer ID Support | 24-bit read-only register returning unique value for 24CS256 - enables automatic part identification in multi-EEPROM systems without hardcoded address assumptions. |
| AEC-Q100 Qualified | Qualified for Automotive Grade 2 (-40°C to +105°C ambient) and extended temperature range (-40°C to +125°C) - validated for under-hood and infotainment applications. |
Applications
| Automotive Infotainment Boot Configuration | Industrial Sensor Calibration Storage |
|---|---|
Use Scenario: Storing bootloader parameters, display resolution settings, and audio equalizer presets in head unit ECUs. IC Role / Device Role / Timing Role: Nonvolatile configuration store accessed during power-on initialization via I²C at 1 MHz; WP pin tied to VSS during programming, VCC during runtime. Use Value: Factory-programmed serial number enables secure firmware signing; ECC prevents corrupted boot flags from causing boot failure. | Use Scenario: Retaining calibrated offset/gain coefficients for pressure and temperature sensors in factory automation nodes. IC Role / Device Role / Timing Role: Persistent parameter storage updated only during calibration cycles; accessed via I²C at 400 kHz with software zone protection isolating active coefficients from test data. Use Value: 1M-cycle endurance supports lifetime recalibration; lockable ID page secures calibration certificates against tampering. |
| Medical Device Usage Logging | Smart Meter Firmware Staging |
Use Scenario: Recording cumulative operational hours, error counters, and last-known-safe state in portable diagnostic equipment. IC Role / Device Role / Timing Role: Low-power logging buffer written once per session; operates at 1.8V with standby current ≤1 µA to extend battery life. Use Value: 200-year data retention ensures audit trail validity over full product lifecycle; ECC guarantees log integrity for regulatory compliance. | Use Scenario: Holding staged firmware images and version metadata prior to atomic OTA update in utility meters. IC Role / Device Role / Timing Role: Dual-bank storage where one bank holds active firmware and the other receives new image via 3.4 MHz I²C; WP pin controls write enable during transfer. Use Value: Page-write capability (64-byte bursts) accelerates image loading; enhanced software protection prevents partial overwrite during power loss. |
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; 1.7V–5.5V; 1M endurance. | Lacks serial number and lockable ID page; no zone-level software write protection. | Select when cost sensitivity outweighs data integrity requirements and AEC-Q100 is not mandated. |
| 24AA256-I/P | Same pinout and basic function; no high-speed mode (>1 MHz); no security register; no ECC; rated for Industrial temp only. | Cannot support 3.4 MHz firmware updates; no factory serial number for device identity; lower reliability margin. | Choose for legacy designs already using 24AA256 footprint and where extended temp or ECC are unnecessary. |
Compared with AT24C256C-SSHL-T and 24AA256-I/P, the 24CS256T-I/CS0668 delivers differentiated value through integrated ECC, AEC-Q100 qualification, and cryptographically useful security features - making it the only option among the three qualified for automotive safety-critical configuration storage.
Availability
24CS256T-I/CS0668 is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor calibration, and medical device usage logging requiring stable component supply and long-term lifecycle support.
Supply support for 24CS256T-I/CS0668 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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 24CS256T-I/CS0668 belongs to Microchip's CS-series serial EEPROM family, engineered specifically for automotive and industrial applications demanding high reliability, secure identity, and robust data integrity under extended temperature and voltage stress.
FAQ
What is the maximum I²C clock frequency supported by the 24CS256T-I/CS0668?
The 24CS256T-I/CS0668 supports up to 3.4 MHz in High-Speed mode when VCC is ≥2.5V and operating within the Industrial temperature range (-40°C to +85°C). At lower voltages (1.7V–2.5V) or Extended temperature range (-40°C to +125°C), the maximum clock frequency is 1 MHz. This is confirmed in Table 1-2 of the DS20005998D datasheet.
Does the 24CS256T-I/CS0668 include Error Correction Code (ECC) functionality?
Yes, the 24CS256T-I/CS0668 incorporates built-in ECC logic that corrects up to one bit error per four-byte readout. The Configuration register includes a read-only Error Correction State (ECS) latch that asserts when ECC correction is applied. This feature is documented in the Features section and Section 1.0 of DS20005998D.
How is the 128-bit serial number implemented in the 24CS256T-I/CS0668?
The 24CS256T-I/CS0668 contains a factory-programmed, globally unique 128-bit serial number stored in the read-only portion of the Security register at addresses 0800h–080Fh. It is guaranteed unique across the entire CS-series EEPROM family and cannot be altered or erased. This is specified in Section 3.2.2 and Figure 3-1 of DS20005998D.
Can the 24CS256T-I/CS0668 be used in automotive applications?
Yes, the 24CS256T-I/CS0668 is AEC-Q100 qualified for Automotive Grade 2 and operates across -40°C to +125°C. Its design includes ESD protection >4000V, >200-year data retention, and 1 million write cycles - meeting stringent reliability requirements for automotive infotainment, body control, and ADAS subsystems per DS20005998D-page 1.
What write protection mechanisms does the 24CS256T-I/CS0668 support?
The 24CS256T-I/CS0668 supports dual write protection: hardware-based via the WP pin (disabling all writes when high), and enhanced software-based via the Configuration register, which enables independent protection of eight 32-Kbit zones. The Configuration register itself can be permanently locked to prevent further changes, as detailed in Sections 3.2.1 and 9.0 of DS20005998D.
24CS256T-I/CS0668 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Type:
- -
- Memory Format:
- EEPROM
- Technology:
- -
- Memory Size:
- 256Kbit
- Memory Organization:
- -
- Memory Interface:
- -
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- -
- Access Time:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
24CS256T-I/CS0668 FAQ
1.How can I place an order for 24CS256T-I/CS0668 through Aetrix?
Please submit a Request for Quotation (RFQ) for 24CS256T-I/CS0668 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/CS0668 reliable?
The price and inventory of 24CS256T-I/CS0668 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/CS0668 is usually 5 days.
3.What payment methods are accepted for 24CS256T-I/CS0668?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24CS256T-I/CS0668 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24CS256T-I/CS0668?
24CS256T-I/CS0668 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24CS256T-I/CS0668 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/CS0668?
For technical support, including 24CS256T-I/CS0668 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24CS256T-I/CS0668 requirements.
6.How does Aetrix verify that 24CS256T-I/CS0668 is sourced from the original manufacturer or authorized distributors?
All 24CS256T-I/CS0668 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/CS0668 meets industry standards.
7.What is the process for return or replacement of 24CS256T-I/CS0668?
All 24CS256T-I/CS0668 units undergo pre-shipment inspection (PSI). If there is an issue with 24CS256T-I/CS0668, 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/CS0668 part is unused and in its original packaging.
Return procedure for 24CS256T-I/CS0668:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
24CS256T-I/CS0668 Tags
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AT24CS02-SSHM-T
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