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Microchip Technology 24CS256T-E/OT66KVAO
- Part No.:
- 24CS256T-E/OT66KVAO
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- SC-74A, SOT-753
- Datasheet:
-
24CS256T-E/OT66KVAO.pdf
- Description:
- IC EEPROM 256KBIT I2C SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,226
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Product details
Overview
24CS256T-E/OT66KVAO from Microchip Technology is a 256-Kbit I²C serial EEPROM organized as 32,768 × 8-bit, supporting byte/page writes (up to 64 bytes), 3.4 MHz High-Speed I²C mode, 1.7V–5.5V operation, and AEC-Q100 automotive qualification. It integrates a 128-bit factory-programmed serial number and ECC logic for error correction in automotive infotainment and ADAS control modules.
For engineers reviewing the 24CS256T-E/OT66KVAO datasheet, 24CS256T-E/OT66KVAO pinout, 24CS256T-E/OT66KVAO application, or 24CS256T-E/OT66KVAO equivalent, key selection considerations include its extended temperature range (–40°C to +125°C), hardware/software write protection options, Security register programmability, and compatibility with legacy 24AA256/24LC256 devices.
Technical Context
The 24CS256T-E/OT66KVAO implements a two-wire I²C interface with Schmitt-trigger inputs, slope-controlled outputs, and configurable High-Speed mode (3.4 MHz at VCC ≥2.5V). Its memory architecture comprises a 256-Kbit main array and a separate 1-Kbit Security register containing a read-only 128-bit serial number and a user-lockable 64-byte ID page.
Write protection is implemented via dual mechanisms: hardware-level WP pin control and software-configurable zone protection using an on-chip Configuration register that can be permanently locked. Built-in ECC corrects single-bit errors per 4-byte readout and reports correction status via an Error Correction State (ECS) latch.
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-write efficiency. |
| I²C Speed Support | Up to 3.4 MHz (High-Speed mode), plus 1 MHz / 400 kHz / 100 kHz - supports high-throughput configuration updates in real-time systems. |
| Operating Voltage | 1.7V to 5.5V - compatible with both low-voltage microcontrollers and legacy 5V industrial buses without level shifting. |
| Temperature Range | –40°C to +125°C (Extended grade) - qualified for under-hood automotive applications and industrial edge controllers. |
| Write Endurance | 1,000,000 cycles - ensures long-term reliability in logging, calibration, and field-upgrade scenarios. |
| Data Retention | >200 years at 55°C - guarantees persistent storage integrity across product lifecycles without refresh. |
| ECC Capability | Corrects up to one bit error per 4-byte read - mitigates soft errors in safety-critical automotive memory access paths. |
Pinout & Package
24CS256T-E/OT66KVAO is packaged in an 8-lead UDFN (2 mm × 3 mm, wettable flank), optimized for automated optical inspection and high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Device Address Input | Hardware-selectable LSB of 3-bit client address; enables up to eight devices on same I²C bus when combined with A1/A2. |
| A1 | Device Address Input | Mid-bit of 3-bit hardware address; must be hardwired to VSS or VCC - not floating - to ensure deterministic device addressing. |
| A2 | Device Address Input | MSB of 3-bit hardware address; sets unique I²C slave address within shared-bus topology. |
| VSS | Ground Reference | Primary return path for all internal circuitry; requires low-impedance connection to system ground plane. |
| SDA | Serial Data Line | Open-drain bidirectional I²C data line; requires external pull-up resistor (330 Ω for 3.4 MHz operation). |
| VCC | Power Supply | Core supply input (1.7–5.5 V); slew rate must not exceed 0.1 V/µs during power-up to avoid POR instability. |
| WP | Write-Protect Control | Active-high hardware lock: tied to VCC disables all writes to main array and Security register; ignored in Enhanced Software Write Protection mode. |
| SCL | Serial Clock Input | Input-only I²C clock line; synchronizes all data transfers; slope control minimizes ground bounce in noisy automotive environments. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-Preprogrammed Serial Number | 128-bit globally unique identifier stored in read-only Security register section - eliminates manufacturing serialization overhead and enables secure device identity binding. |
| Configurable Write Protection | Supports both hardware (WP pin) and software-defined zone protection (eight independent 32-Kbit zones) - allows granular security policy enforcement across firmware, calibration, and user data partitions. |
| Built-In ECC Logic | Single-bit error correction per 4-byte readout with ECS latch reporting - enhances data integrity in EMI-prone automotive domains without host-side correction overhead. |
| I²C Manufacturer ID Function | Returns unique 24-bit device-specific value upon command - enables runtime identification and firmware validation in multi-vendor BOMs. |
| AEC-Q100 Qualified | Qualified to Grade 0 (–40°C to +150°C ambient) stress test conditions - meets automotive reliability requirements for safety-critical ECUs. |
Applications
| Automotive Body Control Module | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing calibrated sensor offsets, door lock actuator profiles, and lighting dimming curves across vehicle lifetime. IC Role / Device Role / Timing Role: Nonvolatile parameter retention IC with guaranteed 200-year data retention and AEC-Q100 compliance for under-dash mounting. Use Value: Eliminates recalibration after battery disconnect and supports over-the-air update rollback via secure, versioned configuration snapshots. |
Use Scenario: Holding ladder logic configuration, I/O mapping tables, and alarm thresholds in modular automation controllers. IC Role / Device Role / Timing Role: Industrial-grade serial EEPROM interfacing with ARM Cortex-M7 PLC host via 1 MHz I²C bus. Use Value: Enables field-replaceable module identification via 128-bit serial number and prevents accidental firmware corruption using dual-mode write protection. |
| Medical Infusion Pump Calibration | Smart Energy Meter Firmware Parameters |
Use Scenario: Archiving dose calibration coefficients, usage logs, and regulatory audit trails in Class II medical devices. IC Role / Device Role / Timing Role: Safety-assured memory element with ECC and lockable Security register for FDA 21 CFR Part 11 compliance. Use Value: Provides tamper-evident storage for critical calibration data; user-programmable ID page stores encrypted device certificates. |
Use Scenario: Storing tariff schedules, metering constants, and cryptographic keys in ANSI C12.22-compliant smart meters. IC Role / Device Role / Timing Role: Secure nonvolatile memory with hardware write-protect and software-configurable zone locking for utility-grade data integrity. Use Value: Meets ANSI/IEEE 1377 security requirements through preprogrammed serial number binding and ECC-protected firmware parameter storage. |
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/SM | No Security register; no ECC; max I²C speed 400 kHz; only Industrial temp (–40°C to +85°C) | Lacks 128-bit serial number and enhanced write protection - unsuitable for automotive or secure identity use cases | Select only for cost-sensitive, non-automotive designs where legacy compatibility and basic EEPROM functionality suffice. |
| AT24C256C-SSHL-T | No built-in ECC; no Security register; no AEC-Q100 qualification; 1 MHz max I²C speed | Not qualified for automotive or extended-temperature industrial use; lacks factory-unique ID for traceability | Choose when sourcing from Atmel/Dialog ecosystem and ECC/security features are not required in commercial-grade applications. |
Compared with 24AA256-I/SM and AT24C256C-SSHL-T, the 24CS256T-E/OT66KVAO delivers differentiated value through AEC-Q100 qualification, ECC-based reliability, and integrated security infrastructure - making it the only option among the three suitable for functional-safety-aware automotive and industrial deployments.
Availability
24CS256T-E/OT66KVAO is available at Aetrix Electronics and suitable for automotive body control, industrial PLC configuration, medical infusion pump calibration, and smart energy meter firmware parameter storage requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for 24CS256T-E/OT66KVAO 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 24CS256 series belongs to Microchip's automotive-qualified serial EEPROM product line, engineered specifically for reliable, secure, and long-life nonvolatile data storage in safety-critical automotive and industrial control systems.
FAQ
What is the package type and footprint of the 24CS256T-E/OT66KVAO?
The 24CS256T-E/OT66KVAO uses an 8-lead UDFN package (2 mm × 3 mm) with wettable flanks, designed for automated optical inspection and high-density PCB assembly. Its pinout matches standard I²C EEPROM footprints, enabling drop-in replacement in existing UDFN-8 layouts with verified thermal and solder-joint reliability per AEC-Q200.
Does the 24CS256T-E/OT66KVAO support High-Speed I²C mode, and what are the voltage requirements?
Yes, the 24CS256T-E/OT66KVAO supports High-Speed I²C mode up to 3.4 MHz, but only when VCC is ≥2.5V and the device is operating within the Industrial temperature range. At 1.7V–2.5V, maximum clock frequency is limited to 1 MHz. This dual-speed capability allows flexible integration across low-power and high-throughput system architectures.
How does the Security register in the 24CS256T-E/OT66KVAO function, and what data does it hold?
The 24CS256T-E/OT66KVAO Security register contains two sections: a read-only 128-bit factory-programmed serial number (address 0800h–080Fh) and a user-programmable, lockable 64-byte ID page (0840h–087Fh). The serial number is globally unique across all CS-series EEPROMs, while the ID page supports irreversible write-protection via software command - ideal for storing cryptographic keys or calibration certificates.
What write protection mechanisms does the 24CS256T-E/OT66KVAO offer, and how do they differ?
The 24CS256T-E/OT66KVAO provides two independent write protection modes: hardware-based (via WP pin) and software-configurable (via Configuration register). Hardware protection locks the entire memory array when WP = VCC. Software protection divides the 256-Kbit array into eight 32-Kbit zones, each individually lockable - offering granular control for mixed-criticality data storage without requiring physical board changes.
Is the 24CS256T-E/OT66KVAO pin-compatible with older Microchip EEPROMs like the 24LC256?
Yes, the 24CS256T-E/OT66KVAO maintains full pin-to-pin and software compatibility with 24AA256, 24LC256, and 24FC256 devices in all common packages including SOIC, TSSOP, and UDFN. Its I²C protocol, address mapping, and timing parameters are backward-compatible - allowing seamless migration to enhanced security and reliability features without layout or firmware modifications.
24CS256T-E/OT66KVAO Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- -
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- I2C
- Clock Frequency:
- 1 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- 400 ns
- Voltage - Supply:
- 1.7V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
24CS256T-E/OT66KVAO FAQ
1.How can I place an order for 24CS256T-E/OT66KVAO through Aetrix?
Please submit a Request for Quotation (RFQ) for 24CS256T-E/OT66KVAO 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-E/OT66KVAO reliable?
The price and inventory of 24CS256T-E/OT66KVAO are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 24CS256T-E/OT66KVAO is usually 5 days.
3.What payment methods are accepted for 24CS256T-E/OT66KVAO?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24CS256T-E/OT66KVAO transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24CS256T-E/OT66KVAO?
24CS256T-E/OT66KVAO orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24CS256T-E/OT66KVAO 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-E/OT66KVAO?
For technical support, including 24CS256T-E/OT66KVAO datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24CS256T-E/OT66KVAO requirements.
6.How does Aetrix verify that 24CS256T-E/OT66KVAO is sourced from the original manufacturer or authorized distributors?
All 24CS256T-E/OT66KVAO 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-E/OT66KVAO meets industry standards.
7.What is the process for return or replacement of 24CS256T-E/OT66KVAO?
All 24CS256T-E/OT66KVAO units undergo pre-shipment inspection (PSI). If there is an issue with 24CS256T-E/OT66KVAO, 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-E/OT66KVAO part is unused and in its original packaging.
Return procedure for 24CS256T-E/OT66KVAO:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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