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Microchip Technology 24CS256-I/SM
- Part No.:
- 24CS256-I/SM
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
24CS256-I/SM.pdf
- Description:
- IC EEPROM 256KBIT I2C 8SOIJ
- Quantity:
- Payment:
- Shipping:
Inventory:450
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Product details
Overview
24CS256-I/SM 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 integrated 128-bit factory-unique serial number. It delivers self-timed write cycles (≤5 ms), built-in ECC for single-bit error correction, and dual write protection (hardware WP pin + software-configurable zone locking), deployed in automotive infotainment control modules for firmware parameter storage.
For engineers reviewing the 24CS256-I/SM datasheet, 24CS256-I/SM pinout, 24CS256-I/SM application, or 24CS256-I/SM equivalent, key selection considerations include I²C bus speed compatibility (100 kHz to 3.4 MHz), voltage range support (1.7V–5.5V), Security register access protocol, ECC latch visibility via Configuration register, and AEC-Q100 qualification for under-hood use.
Technical Context
The 24CS256-I/SM implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress ground bounce and noise. 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 user-programmable lockable ID page (0840h–087Fh).
Device addressing uses three hardware address pins (A0–A2) enabling up to eight devices on one bus, with distinct device address byte formats for main EEPROM (1010xxxx), Security register (1011xxxx), Configuration register (1011xxxx), and Manufacturer ID (1111100x). Write protection is configurable via WP pin (full-array) or Configuration register (eight independent 32-Kbit zones), and the Configuration register can be permanently locked after setup.
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 Support | Up to 3.4 MHz (High-Speed mode), plus 1 MHz / 400 kHz / 100 kHz - supports fast configuration loading in real-time systems. |
| Write Cycle Time | ≤5 ms (self-timed) - eliminates need for external timing control; host can poll ACK or wait fixed interval before next command. |
| Operating Voltage | 1.7V to 5.5V - interoperable across 1.8V logic domains and legacy 5V microcontrollers without level shifters. |
| Data Retention | >200 years at 55°C - ensures long-term reliability in automotive and industrial deployments without refresh. |
| Endurance | 1,000,000 erase/write cycles - sufficient for frequent calibration or logging applications over product lifetime. |
| ECC Capability | Corrects up to one bit error per four-byte read - improves data integrity in electrically noisy environments like vehicle chassis networks. |
Pinout & Package
24CS256-I/SM is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with gull-wing leads, RoHS-compliant matte tin finish, and standard JEDEC MS-012AC footprint (5.3 mm × 4.4 mm × 1.75 mm height). Pin 1 is marked by a beveled corner or notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Hardware Address Input | LSB of 3-bit device address; tied to VSS or VCC to select one of eight possible I²C addresses on shared bus. |
| A1 | Hardware Address Input | Middle bit of 3-bit device address; determines unique client address when multiple 24CS256-I/SM devices share SDA/SCL lines. |
| A2 | Hardware Address Input | MSB of 3-bit device address; required to be logic '0' in SOT-23 variant but fully functional in SOIC package. |
| VSS | Ground Reference | Primary return path for all internal circuits; must be low-impedance connection to system ground plane. |
| SDA | Serial Data I/O | Open-drain bidirectional line; requires external pull-up resistor (value depends on bus speed: 330Ω for 3.4 MHz, 2 kΩ for 1 MHz). |
| VCC | Power Supply | Single supply input (1.7V–5.5V); must ramp monotonically at ≤0.1 V/µs during power-up to avoid POR instability. |
| WP | Write-Protect Control | Active-high enable: tied to VCC disables all writes to main array and Security register; ignored in Enhanced Software Protection mode. |
| SCL | Serial Clock Input | Master-generated clock signal; rising edge samples SDA, falling edge allows SDA transition; slope-controlled to reduce EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-Preprogrammed Serial Number | 128-bit globally unique identifier stored in read-only Security register section (0800h–080Fh), eliminating manufacturing serialization overhead. |
| Configurable Zone Write Protection | Eight independent 32-Kbit memory zones protected via Configuration register - enables selective firmware update partitioning without full-array lock. |
| Built-in Error Correction Code (ECC) | Hardware ECC corrects single-bit errors per 4-byte read; Error Correction State (ECS) latch in Configuration register signals correction event for diagnostics. |
| I²C Manufacturer ID Function | 24-bit read-only register returns unique value (0x00001D) confirming device identity - prevents misidentification in multi-vendor BOMs. |
| AEC-Q100 Qualified | Qualified to Grade 1 (-40°C to +125°C) per AEC-Q100 Rev H - validated for automotive powertrain, body control, and ADAS subsystems. |
Applications
| Automotive Body Control Module | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing seat position presets, mirror angles, and lighting profiles in OEM vehicle BCMs. IC Role / Device Role / Timing Role: Nonvolatile parameter retention IC with AEC-Q100 qualification and >200-year data retention. Use Value: Eliminates need for external backup battery or capacitor; factory-serialized units enable secure OTA update binding. | Use Scenario: Holding calibrated sensor offsets, I/O mapping tables, and firmware revision stamps in modular PLC backplanes. IC Role / Device Role / Timing Role: High-reliability I²C EEPROM interfacing with ARM Cortex-M7 controllers via 1 MHz bus. Use Value: ECC and 1M-cycle endurance ensure stable operation across 15+ year industrial deployment lifetimes. |
| Medical Infusion Pump Calibration | Smart Energy Meter Firmware Vault |
Use Scenario: Securing drug delivery calibration constants and usage logs subject to FDA 21 CFR Part 11 audit trails. IC Role / Device Role / Timing Role: Tamper-resistant memory with lockable Security register ID page (0840h–087Fh) for cryptographic key binding. Use Value: Preprogrammed 128-bit serial number provides immutable device identity for regulatory traceability. | Use Scenario: Storing tariff schedules, metering firmware signatures, and tamper-event logs in ANSI C12.22-compliant smart meters. IC Role / Device Role / Timing Role: Dual-protection EEPROM (WP pin + software zone lock) preventing unauthorized firmware modification. Use Value: Enhanced software write protection allows field-upgradable security policies without hardware redesign. |
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 Security register; no 128-bit serial number; max I²C speed 1 MHz; no ECC; operates 1.7V–5.5V. | Lacks factory serialization and ECC - suitable only for cost-sensitive non-automotive applications where data integrity is less critical. | Select when AEC-Q100, ECC, or unique ID are unnecessary and bill-of-materials cost is primary constraint. |
| 24AA256-I/SN | Same pinout and basic functionality; no Security register; no ECC; max I²C speed 400 kHz; operates 1.8V–5.5V. | Not AEC-Q100 qualified; lower speed limits use in high-throughput systems; lacks diagnostic ECS latch. | Choose for legacy industrial designs already using Microchip's 24AA family where upgrade path prioritizes footprint compatibility over enhanced features. |
Compared with AT24C256C-SSHL-T and 24AA256-I/SN, the 24CS256-I/SM adds factory-unique identification, hardware ECC, AEC-Q100 qualification, and 3.4 MHz I²C - making it the only option among the three qualified for safety-critical automotive and medical applications requiring traceability and error resilience.
Availability
24CS256-I/SM is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial programmable logic controllers, medical infusion pumps, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 24CS256-I/SM 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 manufacturer specializing in microcontrollers, analog devices, and memory solutions, with global design centers and ISO/TS 16949-certified wafer fabs.
The 24CS256-I/SM belongs to Microchip's CS-series serial EEPROM product line, engineered specifically for automotive-grade reliability, secure device identity, and robust operation in electrically noisy, wide-temperature environments.
FAQ
What is the maximum I²C clock frequency supported by the 24CS256-I/SM?
The 24CS256-I/SM supports High-Speed mode up to 3.4 MHz when VCC is ≥2.5V and ambient temperature is within the Industrial range (–40°C to +85°C). At lower voltages (1.7V–2.5V) or Extended temperature (–40°C to +125°C), maximum clock frequency is 1 MHz. This enables faster firmware updates in automotive head units while maintaining compatibility with legacy 400 kHz industrial controllers.
How does the Security register in the 24CS256-I/SM differ from standard EEPROM memory?
The Security register in the 24CS256-I/SM is a separate 1-Kbit block with two distinct sections: a read-only 128-bit factory-programmed serial number (0800h–080Fh), and a user-programmable, lockable 64-byte ID page (0840h–087Fh). Unlike main array writes, Security register programming requires specific address byte sequences (1011xxxx) and proper Stop condition termination - ensuring secure, isolated storage for cryptographic keys or device certificates.
Can the 24CS256-I/SM replace the 24LC256 in an existing design without changes?
The 24CS256-I/SM is backward compatible with 24LC256 in pinout, basic I²C protocol, and memory map, but introduces new features including Security register access, ECC, and Configuration register locking. To retain full functionality, firmware must be updated to handle ECS latch polling and optional zone protection. For drop-in replacement without feature use, no PCB changes are needed - however, WP pin behavior remains identical and voltage range (1.7V–5.5V) matches.
What is the purpose of the Error Correction State (ECS) latch in the 24CS256-I/SM Configuration register?
The ECS latch in the 24CS256-I/SM Configuration register is a read-only status bit that is set to '1' whenever the built-in ECC logic corrects a single-bit error during a read operation. It remains set until cleared by a power cycle or hardware reset, allowing host firmware to log integrity events or trigger diagnostic routines - providing observable evidence of memory stress or EMI exposure in mission-critical systems.
Is the 24CS256-I/SM suitable for use in AEC-Q100 Grade 0 applications?
No - the 24CS256-I/SM is qualified to AEC-Q100 Grade 1 (–40°C to +125°C), not Grade 0 (–40°C to +150°C). Its specified extended temperature range is –40°C to +125°C, and absolute maximum storage temperature is +150°C. For under-hood applications exceeding +125°C ambient, such as near turbochargers or exhaust manifolds, Grade 0 qualified alternatives must be selected; the 24CS256-I/SM is appropriate for cabin, chassis, and most powertrain control modules.
24CS256-I/SM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tube
- 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-SOIJ
24CS256-I/SM FAQ
1.How can I place an order for 24CS256-I/SM through Aetrix?
Please submit a Request for Quotation (RFQ) for 24CS256-I/SM 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 24CS256-I/SM reliable?
The price and inventory of 24CS256-I/SM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 24CS256-I/SM is usually 5 days.
3.What payment methods are accepted for 24CS256-I/SM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24CS256-I/SM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24CS256-I/SM?
24CS256-I/SM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24CS256-I/SM 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 24CS256-I/SM?
For technical support, including 24CS256-I/SM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24CS256-I/SM requirements.
6.How does Aetrix verify that 24CS256-I/SM is sourced from the original manufacturer or authorized distributors?
All 24CS256-I/SM 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 24CS256-I/SM meets industry standards.
7.What is the process for return or replacement of 24CS256-I/SM?
All 24CS256-I/SM units undergo pre-shipment inspection (PSI). If there is an issue with 24CS256-I/SM, 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 24CS256-I/SM part is unused and in its original packaging.
Return procedure for 24CS256-I/SM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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