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Microchip Technology 24CS256-E/SN
- Part No.:
- 24CS256-E/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
24CS256-E/SN.pdf
- Description:
- IC EEPROM 256KBIT I2C 1MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:661
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Product details
Overview
24CS256-E/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 operation from 1.7V to 5.5V. It integrates a 128-bit factory-programmed serial number, 64-byte user-lockable ID page, and built-in ECC for single-bit error correction - deployed in automotive infotainment control units for firmware parameter storage.
For engineers reviewing the 24CS256-E/SN datasheet, 24CS256-E/SN pinout, 24CS256-E/SN application, or 24CS256-E/SN equivalent, key selection considerations include High-Speed I²C support up to 3.4 MHz, dual write-protection modes (hardware WP pin + software-configurable zone protection), AEC-Q100 qualification, and extended temperature range (–40°C to +125°C) for under-hood electronics.
Technical Context
The 24CS256-E/SN implements a two-wire I²C interface with Schmitt-trigger inputs, slope-controlled outputs, and programmable High-Speed mode (3.4 MHz at VCC ≥2.5V). Its memory architecture comprises a 256-Kbit main array (0000h–7FFFh) and a separate 1-Kbit Security register containing read-only 128-bit serial number (0800h–080Fh) and user-programmable lockable ID page (0840h–087Fh).
Device behavior is modulated via a Configuration register enabling enhanced software write protection across eight independent 32-Kbit zones; once locked, it becomes read-only. The ECC logic corrects one bit per four-byte readout and sets an Error Correction State (ECS) latch in the Configuration register upon correction.
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 block-level updates without full-array erasure. |
| I²C Speed Support | Up to 3.4 MHz (High-Speed mode), plus 1 MHz / 400 kHz / 100 kHz - supports high-throughput configuration loading in real-time systems. |
| Write Cycle Time | ≤5 ms max (self-timed); no external polling required - simplifies firmware timing and reduces host CPU overhead. |
| Operating Voltage | 1.7V to 5.5V - interoperable with 1.8V, 3.3V, and 5V logic domains without level shifters. |
| Data Retention | >200 years at 55°C - ensures long-term reliability in unattended industrial or automotive deployments. |
| Endurance | 1,000,000 erase/write cycles - validated for applications requiring frequent calibration or logging updates. |
| Temperature Range | –40°C to +125°C (Extended grade) - qualified per AEC-Q100 Grade 1 for automotive powertrain and body control modules. |
| ESD Protection | >4000V HBM - robust against handling and system-level electrostatic discharge in manufacturing and field environments. |
Pinout & Package
24CS256-E/SN is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with gull-wing leads, RoHS-compliant matte tin finish, and JEDEC MS-012AC footprint (5.3mm × 5.3mm × 1.75mm height). Pin 1 marked by notch or dot; pin 1 corner located at top-left when notch faces up.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Hardware Device Address Input | LSB of 3-bit client address; hardwired to VSS or VCC to enable up to 8 devices on same I²C bus - critical for multi-node sensor clusters. |
| A1 | Hardware Device Address Input | Middle bit of 3-bit client address; must be stable before I²C communication begins - prevents bus arbitration conflicts. |
| A2 | Hardware Device Address Input | MSB of 3-bit client address; tied low in SOT-23 variants but fully functional in SOIC - defines unique 7-bit I²C slave address (1010xxxR/W). |
| 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. |
| SDA | Serial Data Bidirectional Line | Open-drain I²C data line; requires external pull-up resistor (330Ω for 3.4 MHz); changes only during SCL low - enforces strict I²C protocol compliance. |
| SCL | Serial Clock Input | Master-generated clock synchronizing all data transfers; Schmitt-trigger input rejects noise; slope control minimizes ground bounce during fast edges. |
| WP | Hardware Write-Protect Input | Active-high pin disabling all writes to main array and Security register when driven to VCC - provides fail-safe protection during power-up or fault conditions. |
| VCC | Power Supply Input | 1.7V–5.5V supply; internal POR circuit holds device in reset until VCC ≥1.5V and stabilizes for ≥100 µs - prevents spurious writes during brown-out. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-Programmed 128-Bit Serial Number | Unique identifier preloaded in Security register (0800h–080Fh); eliminates manufacturing serialization steps and enables secure device binding in firmware. |
| User-Programmable & Lockable ID Page | 64-byte EEPROM section (0840h–087Fh) that can be permanently write-locked via software sequence - ideal for storing immutable calibration or cryptographic keys. |
| Built-In ECC Logic | Corrects single-bit errors within any 4-byte read window and asserts ECS latch in Configuration register - increases effective data integrity without host-side error-handling overhead. |
| Dual Write-Protection Modes | Hardware WP pin (full-array protection) + software-configurable zone protection (eight 32-Kbit regions) - allows granular security policy enforcement per application partition. |
| I²C Manufacturer ID Register | 24-bit read-only register returning unique value for 24CS256 - enables automatic device identification and firmware version validation during system boot. |
| AEC-Q100 Automotive Qualification | Qualified to Grade 1 (–40°C to +125°C) with full reliability testing (HTOL, TC, UHAST) - meets requirements for safety-critical automotive subsystems. |
Applications
| Automotive Body Control Module | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing seat position presets, mirror angles, and lighting profiles in vehicle door modules. IC Role / Device Role / Timing Role: Nonvolatile parameter storage with AEC-Q100 compliance and ECC-protected reads during CAN-based diagnostics. Use Value: Prevents loss of user preferences after battery disconnect; 200-year retention ensures lifetime functionality without replacement. |
Use Scenario: Holding firmware update metadata, I/O mapping tables, and calibration coefficients in modular automation controllers. IC Role / Device Role / Timing Role: Secure, field-updatable configuration store interfaced via isolated I²C to microcontroller's peripheral bus. Use Value: Enables zero-downtime reconfiguration; hardware WP pin blocks accidental overwrites during hot-swap maintenance. |
| Medical Infusion Pump Calibration | Smart Energy Meter Firmware Parameters |
Use Scenario: Archiving dose calibration constants, operator audit logs, and safety interlock settings in Class II medical devices. IC Role / Device Role / Timing Role: Tamper-resistant storage with lockable ID page for regulatory traceability and secure boot verification. Use Value: Meets IEC 62304 software lifecycle requirements; 1M endurance supports daily recalibration over 10+ years. |
Use Scenario: Retaining tariff schedules, metering history, and cryptographic keys in ANSI C12.22-compliant smart meters. IC Role / Device Role / Timing Role: High-reliability EEPROM interfaced to metrology SoC via 3.4 MHz I²C for rapid parameter load during wake-up cycles. Use Value: 1.7V operation ensures functionality during brown-out events; >4 kV ESD protects against utility-side transients. |
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 or lockable ID page; max I²C speed 1 MHz; no AEC-Q100 qualification. | Lacks hardware-assisted device identity and enhanced write protection - unsuitable for automotive or regulated medical use. | Select only for cost-sensitive consumer applications where serialization and zone-level protection are unnecessary. |
| 24AA256-I/SN | Same pinout and basic I²C interface, but no ECC, no Security register, no High-Speed mode (>1 MHz), and Industrial-grade only (–40°C to +85°C). | Lower reliability and narrower temperature range limit use to non-automotive embedded systems with relaxed uptime requirements. | Choose when legacy compatibility with older Microchip EEPROMs is required and ECC/extended temp are not design constraints. |
Compared with AT24C256C-SSHL-T and 24AA256-I/SN, the 24CS256-E/SN delivers certified automotive reliability, integrated device identity, and ECC-protected data integrity - making it the sole option among the three qualified for safety-critical, long-lifecycle, and secure-parameter applications.
Availability
24CS256-E/SN is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC configuration storage, and medical infusion pump calibration requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for 24CS256-E/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, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 24CS256 belongs to Microchip's CS-series serial EEPROM family, designed specifically for automotive, industrial, and medical applications demanding AEC-Q100 qualification, enhanced security features, and extended temperature operation.
FAQ
What is the maximum I²C clock frequency supported by the 24CS256-E/SN?
The 24CS256-E/SN supports High-Speed I²C mode up to 3.4 MHz when VCC is ≥2.5V and operating in Industrial temperature range. At lower voltages (1.7V–2.5V) or Extended temperature range, maximum clock frequency is 1 MHz. This enables faster configuration loads in time-critical systems while maintaining compatibility with legacy 100 kHz and 400 kHz designs.
Does the 24CS256-E/SN require external pull-up resistors on SDA and SCL lines?
Yes, the 24CS256-E/SN requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. Recommended values are 330Ω for 3.4 MHz operation, 2 kΩ for 1 MHz/400 kHz, and 10 kΩ for 100 kHz - selected based on bus capacitance and rise-time requirements per I²C specification.
How is write protection implemented on the 24CS256-E/SN?
The 24CS256-E/SN implements dual write protection: (1) Hardware via the WP pin - tying WP to VCC disables all writes to main memory and Security register; (2) Software via the Configuration register - enabling zone-level protection across eight 32-Kbit segments, configurable and lockable independently. Both modes coexist and can be used simultaneously.
What is the purpose of the Security register in the 24CS256-E/SN?
The Security register in the 24CS256-E/SN is a dedicated 1-Kbit area split into two sections: a read-only 128-bit factory-programmed serial number (0800h–080Fh) for unique device identification, and a user-programmable 64-byte ID page (0840h–087Fh) that can be permanently locked via software. It enables secure device binding, calibration anchoring, and tamper-resistant credential storage.
Is the 24CS256-E/SN pin-compatible with the 24LC256 or 24AA256?
Yes, the 24CS256-E/SN is backward compatible and pin-compatible with 24AA256, 24LC256, and 24FC256 in identical packages (e.g., SOIC-8), sharing the same A0/A1/A2/VSS/SDA/SCL/WP/VCC pinout and basic I²C command set. However, advanced features like ECC, Security register, and High-Speed mode require updated firmware initialization sequences.
What does the Error Correction State (ECS) latch indicate in the 24CS256-E/SN?
The Error Correction State (ECS) latch is a read-only flag in the Configuration register that is set whenever the built-in ECC logic successfully corrects a single-bit error during a read operation. It remains asserted until cleared by a read of the Configuration register, allowing host firmware to log or respond to memory integrity events without interrupting normal operation.
24CS256-E/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm 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:
- 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:
- 8-SOIC
24CS256-E/SN FAQ
1.How can I place an order for 24CS256-E/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 24CS256-E/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 24CS256-E/SN reliable?
The price and inventory of 24CS256-E/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 24CS256-E/SN is usually 5 days.
3.What payment methods are accepted for 24CS256-E/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24CS256-E/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24CS256-E/SN?
24CS256-E/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24CS256-E/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 24CS256-E/SN?
For technical support, including 24CS256-E/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24CS256-E/SN requirements.
6.How does Aetrix verify that 24CS256-E/SN is sourced from the original manufacturer or authorized distributors?
All 24CS256-E/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 24CS256-E/SN meets industry standards.
7.What is the process for return or replacement of 24CS256-E/SN?
All 24CS256-E/SN units undergo pre-shipment inspection (PSI). If there is an issue with 24CS256-E/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 24CS256-E/SN part is unused and in its original packaging.
Return procedure for 24CS256-E/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
24CS256-E/SN Tags
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