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Microchip Technology 24CS256T-I/Q4B
- Part No.:
- 24CS256T-I/Q4B
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-UFDFN Exposed Pad
- Datasheet:
-
24CS256T-I/Q4B.pdf
- Description:
- IC EEPROM 256KBIT I2C 8UDFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,109
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Product details
Overview
24CS256T-I/Q4B 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 unique 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/Q4B datasheet, 24CS256T-I/Q4B pinout, 24CS256T-I/Q4B application, or 24CS256T-I/Q4B equivalent, key selection considerations include its AEC-Q100 qualification, 1.7V–5.5V operating range, industrial temperature rating (–40°C to +85°C), wettable flank VDFN-8 package, and dual-zone write protection via Configuration register.
Technical Context
The 24CS256T-I/Q4B implements a two-wire I²C interface with Schmitt-trigger inputs, slope-controlled outputs, and support for standard (100/400 kHz), fast (1 MHz), and high-speed (3.4 MHz) modes. Its memory architecture comprises a 256-Kbit main array and a separate 1-Kbit Security register split into read-only 128-bit serial number (0800h–080Fh) and programmable/lockable 64-byte ID page (0840h–087Fh).
Write protection is configurable via hardware WP pin (full-array lock) or software-defined zones (eight independent 32-Kbit regions) using the Configuration register - which itself can be permanently locked. Built-in ECC corrects one bit per four-byte read, with an Error Correction State (ECS) latch reporting correction events.
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 - compatible with modern microcontrollers without clock stretching bottlenecks. |
| Write Cycle Time | ≤5 ms max (self-timed), no external polling required - simplifies host firmware timing and reduces bus occupancy. |
| Operating Voltage | 1.7V to 5.5V - supports direct interfacing with 1.8V, 3.3V, and 5V logic domains without level shifters. |
| Temperature Range | Industrial grade: –40°C to +85°C - validated for under-hood and dashboard-mounted automotive electronics. |
| Data Retention | >200 years at 55°C - ensures long-term reliability in safety-critical configuration storage applications. |
| Endurance | 1,000,000 write/erase cycles - suitable for dynamic calibration data logging with frequent updates. |
Pinout & Package
24CS256T-I/Q4B is packaged in an 8-lead Wettable Flank VDFN (Q4B), optimized for automated optical inspection (AOI) and solder joint reliability in automotive PCB assemblies.
| 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 tied to VSS or VCC. |
| A1 | Device Address Input | Mid-bit of 3-bit hardware address; must be hard-wired for deterministic multi-device addressing. |
| A2 | Device Address Input | MSB of 3-bit hardware address; determines unique I²C slave address (1010A2A1A0R/W). |
| 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 (330Ω for 3.4 MHz operation). |
| SCL | Serial Clock Input | Input-only I²C clock line; synchronizes all data transfers; slope control minimizes ground bounce. |
| 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. |
| VCC | Power Supply | Single supply input (1.7–5.5V); powers EEPROM core, I²C interface, and ECC logic; decoupling capacitor required. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-Programmed 128-Bit Serial Number | Globally unique identifier preloaded in Security register (0800h–080Fh), eliminating manufacturing serialization overhead. |
| User-Programmable & Lockable ID Page | 64-byte EEPROM section (0840h–087Fh) that can be permanently write-locked via software sequence - ideal for storing immutable device keys or calibration certificates. |
| Built-In Error Correction Code (ECC) | Corrects single-bit errors within any four-byte read window; ECS latch flags correction events for host diagnostics and data integrity monitoring. |
| Enhanced Software Write Protection | Configurable via Configuration register to protect eight independent 32-Kbit zones - enables granular firmware update partitioning without hardware WP dependency. |
| AEC-Q100 Qualified | Validated for automotive applications per Grade 2 (–40°C to +105°C ambient) stress testing - meets reliability requirements for powertrain and ADAS subsystems. |
Applications
| Automotive Infotainment | Industrial PLC Configuration |
|---|---|
Use Scenario: Storing UI language settings, display brightness profiles, and Bluetooth pairing history across vehicle ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile configuration storage with secure, field-updatable parameters accessed via I²C during boot and runtime. Use Value: 128-bit serial number enables anti-cloning; ECC ensures data integrity over 15+ year vehicle lifespan; AEC-Q100 qualification guarantees operation in thermally aggressive dash environments. |
Use Scenario: Retaining I/O mapping tables, PID tuning coefficients, and alarm thresholds after power loss in factory automation controllers. IC Role / Device Role / Timing Role: High-reliability parameter retention element interfaced to ARM Cortex-M7-based PLC CPU via 1 MHz I²C. Use Value: 1M-cycle endurance supports daily recalibration; software zone protection isolates critical firmware parameters from user-modifiable settings; 1.7V operation enables brown-out resilience. |
| Medical Device Calibration | Smart Energy Metering |
Use Scenario: Archiving sensor offset/gain coefficients and regulatory audit logs in portable diagnostic equipment. IC Role / Device Role / Timing Role: Tamper-evident calibration vault with cryptographically verifiable serial number and lockable ID page. Use Value: Preprogrammed serial number serves as hardware root-of-trust; lockable 64-byte ID page stores digital signatures of calibration certificates; >200-year data retention satisfies FDA long-term recordkeeping mandates. |
Use Scenario: Storing tariff schedules, metering firmware version history, and cryptographic keys in ANSI C12.22-compliant smart meters. IC Role / Device Role / Timing Role: Secure nonvolatile memory for utility-grade data integrity, accessed via isolated I²C interface. Use Value: Hardware WP pin provides physical write disable during firmware updates; ECC prevents silent corruption of billing-critical registers; RoHS compliance meets global energy infrastructure regulations. |
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 serial number and lockable ID page; unsuitable for automotive or security-sensitive use cases. | Select only for cost-sensitive consumer applications where ECC and serialization are unnecessary. |
| 24AA256-I/P | Same pinout but PDIP-8 package; no wettable flank; no AEC-Q100; no 3.4 MHz support; no 128-bit serial number. | Legacy through-hole assembly; limited to industrial temp (–40°C to +85°C) but lacks automotive validation and advanced security features. | Choose only for prototyping or legacy board refresh where surface-mount constraints or automotive qualification are not required. |
Compared with AT24C256C-SSHL-T and 24AA256-I/P, the 24CS256T-I/Q4B delivers differentiated value through AEC-Q100 qualification, ECC-enabled data integrity, factory-serialized identity, and software-configurable zone protection - making it the sole option among the three qualified for safety-critical automotive and medical deployments.
Availability
24CS256T-I/Q4B is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC configuration storage, and medical device calibration archiving requiring stable component supply across extended product lifecycles.
Supply support for 24CS256T-I/Q4B 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with a focus on embedded control and connectivity.
The 24CS256T-I/Q4B belongs to Microchip's CS-series serial EEPROM family, designed specifically for automotive, industrial, and medical applications demanding enhanced security, reliability, and long-term data integrity in harsh environments.
FAQ
What is the package type of the 24CS256T-I/Q4B?
The 24CS256T-I/Q4B uses an 8-lead Wettable Flank VDFN package (Q4B footprint), featuring exposed side-wettable flanks for reliable automated optical inspection (AOI) and solder joint quality verification - essential for automotive-grade manufacturing yield assurance.
Does the 24CS256T-I/Q4B support high-speed I²C mode?
Yes, the 24CS256T-I/Q4B supports I²C High-Speed mode up to 3.4 MHz when operated at VCC ≥2.5V and within the industrial temperature range. This enables faster firmware parameter loading and reduces I²C bus contention in systems with multiple EEPROMs or sensors.
How does the built-in ECC function in the 24CS256T-I/Q4B?
The 24CS256T-I/Q4B implements on-die ECC that automatically corrects single-bit errors within any four-byte read window. The Configuration register includes a read-only Error Correction State (ECS) latch that asserts when correction occurs - enabling host firmware to log integrity events without additional external logic.
Can the 128-bit serial number in the 24CS256T-I/Q4B be overwritten?
No - the 128-bit serial number in the 24CS256T-I/Q4B is factory-programmed, globally unique, and permanently read-only (located at addresses 0800h–080Fh). It cannot be altered, erased, or reprogrammed, providing a hardware-enforced identity anchor for anti-counterfeiting and secure boot applications.
What write protection options does the 24CS256T-I/Q4B offer?
The 24CS256T-I/Q4B offers dual write protection: (1) hardware-based full-array lock via the WP pin, and (2) software-configurable protection of eight independent 32-Kbit zones via the Configuration register - which can itself be permanently locked to prevent further changes to protection policy.
24CS256T-I/Q4B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-UFDFN Exposed Pad
- 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-UDFN (2x3)
24CS256T-I/Q4B FAQ
1.How can I place an order for 24CS256T-I/Q4B through Aetrix?
Please submit a Request for Quotation (RFQ) for 24CS256T-I/Q4B 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/Q4B reliable?
The price and inventory of 24CS256T-I/Q4B 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/Q4B is usually 5 days.
3.What payment methods are accepted for 24CS256T-I/Q4B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24CS256T-I/Q4B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24CS256T-I/Q4B?
24CS256T-I/Q4B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24CS256T-I/Q4B 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/Q4B?
For technical support, including 24CS256T-I/Q4B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24CS256T-I/Q4B requirements.
6.How does Aetrix verify that 24CS256T-I/Q4B is sourced from the original manufacturer or authorized distributors?
All 24CS256T-I/Q4B 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/Q4B meets industry standards.
7.What is the process for return or replacement of 24CS256T-I/Q4B?
All 24CS256T-I/Q4B units undergo pre-shipment inspection (PSI). If there is an issue with 24CS256T-I/Q4B, 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/Q4B part is unused and in its original packaging.
Return procedure for 24CS256T-I/Q4B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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