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Microchip Technology 24CS256-E/P
- Part No.:
- 24CS256-E/P
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
24CS256-E/P.pdf
- Description:
- IC EEPROM 256KBIT I2C 1MHZ 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:345
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Product details
Overview
24CS256-E/P 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 storage, industrial sensor calibration data retention, and embedded system configuration backup.
For engineers reviewing the 24CS256-E/P datasheet, 24CS256-E/P pinout, 24CS256-E/P application, or 24CS256-E/P equivalent, key selection considerations include its AEC-Q100 qualification, dual write-protection modes (hardware WP pin + software-configurable zone protection), 1 µA standby current at 5.5V, and compatibility with legacy 24AA256/24LC256 devices in shared-bus systems.
Technical Context
The 24CS256-E/P implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and ground bounce. Its internal architecture separates the 256-Kbit main array from a dedicated 1-Kbit Security register containing read-only serial number and programmable ID page.
Write operations use self-timed cycles (≤5 ms) with automatic address incrementing during page writes (up to 64 bytes/page). The Configuration register enables permanent locking of enhanced software write protection across eight independent 32-Kbit zones - distinct from legacy full-array hardware WP pin control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbits (32,768 × 8-bit), organized in 512 pages of 64 bytes each - enables efficient block-level firmware parameter storage. |
| I²C Speed Modes | Supports 100 kHz, 400 kHz, 1 MHz, and 3.4 MHz High-Speed mode - allows flexible timing margining in noise-sensitive automotive ECUs. |
| Operating Voltage | 1.7V to 5.5V - interoperable with both 1.8V logic and 5V legacy microcontrollers without level-shifting. |
| Write Endurance | 1,000,000 erase/write cycles - suitable for frequent calibration updates in industrial sensors. |
| Data Retention | >200 years at 55°C - ensures long-term reliability in sealed automotive modules with no field maintenance. |
| ESD Protection | >4000 V HBM - meets robustness requirements for assembly-line handling and in-vehicle ESD events. |
| Temperature Range | Extended (E): –40°C to +125°C - qualified per AEC-Q100 Grade 1 for under-hood automotive applications. |
Pinout & Package
24CS256-E/P is supplied in an 8-lead PDIP package with through-hole mounting and standard 0.3-inch body width. Pin functions are electrically identical across all supported packages including SOIC, TSSOP, and UDFN.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Device Address Input | Hardware-selectable LSB of 3-bit client address; tied high/low to enable up to 8 devices on same I²C bus. |
| A1 | Device Address Input | Middle bit of 3-bit hardware address; required to be logic '0' in SOT-23 variant but fully configurable in PDIP. |
| A2 | Device Address Input | MSB of 3-bit hardware address; determines unique I²C slave address when combined with A1/A0. |
| VSS | Ground Reference | Primary return path for all internal circuitry and I/O; must be low-impedance connection in automotive PCB layouts. |
| SDA | Serial Data Line | Open-drain bidirectional I²C data line requiring external pull-up; supports clock stretching and ACK/NACK signaling. |
| SCL | Serial Clock Line | Input-only I²C clock; accepts 3.4 MHz edges with controlled rise/fall times to meet HS-mode timing (THIGH ≥60 ns). |
| WP | Write-Protect Control | Active-high hardware lock: tied to VCC disables all writes to main array and Security register; ignored in enhanced software protection mode. |
| VCC | Power Supply | Single supply input supporting 1.7–5.5V; includes internal POR circuit with 100 µs TPUP delay before command acceptance. |
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. |
| Built-in ECC Logic | Corrects up to one bit error per 4-byte read; Error Correction State (ECS) latch in Configuration register flags correction events for diagnostics. |
| Dual Write-Protection Architecture | Hardware WP pin for full-array lock + software-configurable zone protection across eight 32-Kbit blocks - enables granular security for firmware vs. user data. |
| I²C Manufacturer ID Support | Returns unique 24-bit device-specific value via standardized I²C Manufacturer Identification command - simplifies runtime identification in multi-vendor BOMs. |
| Enhanced Software Locking | User-programmable 64-byte ID page can be permanently locked via software sequence - prevents tampering with calibration or licensing data. |
Applications
| Automotive Body Control Module | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing seat position presets, mirror angles, and lighting profiles in vehicle body control units. IC Role / Device Role / Timing Role: Nonvolatile configuration memory with AEC-Q100 qualification and 125°C operation for under-dash mounting. Use Value: Eliminates need for external serialization by leveraging factory-programmed 128-bit serial number for vehicle-specific profile binding. |
Use Scenario: Retaining I/O mapping, PID tuning parameters, and firmware update history in programmable logic controllers. IC Role / Device Role / Timing Role: High-reliability data logger with 1M write cycles and ECC - withstands daily recalibration in factory automation. Use Value: Dual protection modes allow separate locking of factory-calibrated values (via WP pin) and field-updated parameters (via software zones). |
| Medical Infusion Pump Calibration | Smart Energy Meter Firmware Backup |
Use Scenario: Securing dose calibration coefficients and usage logs in battery-powered infusion pumps. IC Role / Device Role / Timing Role: Low-power EEPROM with 1 µA standby current and 1.7V minimum VCC - extends battery life between charges. Use Value: Built-in ECC ensures integrity of critical drug dosage data even after years of storage at elevated temperatures. |
Use Scenario: Backing up meter firmware, tariff tables, and cryptographic keys in utility-grade smart meters. IC Role / Device Role / Timing Role: Tamper-resistant storage with lockable 64-byte ID page for secure key injection during production. Use Value: I²C Manufacturer ID function enables automated verification of authentic Microchip parts during meter commissioning. |
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/P | No Security register; no 128-bit serial number; no ECC; max I²C speed = 1 MHz; only Industrial temp (–40°C to +85°C). | Lacks AEC-Q100 qualification and extended temperature support - unsuitable for automotive under-hood use. | Select when cost sensitivity outweighs security, ECC, and automotive qualification requirements. |
| AT24C256C-PU | No Security register; no ECC; no High-Speed mode (max 1 MHz); different device addressing scheme; no Manufacturer ID register. | Not AEC-Q100 qualified; lacks hardware/software dual write protection - limited to consumer-grade applications. | Choose only for legacy designs already using AT24C256 footprint and where serial number/ECC are unnecessary. |
Compared with 24AA256-I/P and AT24C256C-PU, the 24CS256-E/P delivers differentiated value through factory-serialized identity, ECC-enabled data integrity, AEC-Q100 compliance, and flexible dual-mode write protection - making it the sole option among these three qualified for safety-critical automotive and industrial deployments.
Availability
24CS256-E/P 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/P 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 belongs to Microchip's CS-series serial EEPROM family, engineered specifically for automotive and industrial applications demanding enhanced security, reliability, and extended temperature operation beyond legacy EEPROM offerings.
FAQ
What is the maximum I²C clock frequency supported by the 24CS256-E/P?
The 24CS256-E/P supports High-Speed mode up to 3.4 MHz when operating at VCC ≥ 2.5V and within the Industrial temperature range. At lower voltages (1.7V–2.5V) or Extended temperature range, maximum clock frequency is 1 MHz. This enables faster firmware updates in automotive ECUs while maintaining signal integrity via built-in slope control on SDA/SCL lines.
Does the 24CS256-E/P require external pull-up resistors on SDA and SCL lines?
Yes, the 24CS256-E/P requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. Recommended values are 330 Ω for 3.4 MHz operation, 2 kΩ for 1 MHz, and 10 kΩ for 100 kHz - selected based on bus capacitance and desired rise time per I²C specification.
How does the Security register in the 24CS256-E/P differ from the main memory array?
The Security register in the 24CS256-E/P is a physically separate 1-Kbit structure: its first 16 bytes contain a factory-programmed, globally unique 128-bit serial number (read-only), and the next 64 bytes form a user-programmable, lockable ID page. Unlike the main 256-Kbit array, this register supports dedicated access via distinct I²C address bits and enables irreversible protection of sensitive data.
Can the 24CS256-E/P replace a 24LC256 in an existing design without changes?
The 24CS256-E/P is backward compatible with 24LC256 in pinout, basic I²C protocol, and memory organization, but adds new features including Security register access, ECC, and High-Speed mode. To retain full functionality, firmware must be updated to handle new address mappings for Security/Configuration registers and optional ECC status checking - no PCB changes are needed.
What write protection options are available on the 24CS256-E/P?
The 24CS256-E/P offers two independent write protection mechanisms: (1) Hardware-based full-array lock via the WP pin tied to VCC, and (2) Software-configurable protection of any of eight 32-Kbit zones using the Configuration register. Once configured, the register can be permanently locked to prevent further modification - enabling layered security for firmware and user data.
24CS256-E/P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
24CS256-E/P FAQ
1.How can I place an order for 24CS256-E/P through Aetrix?
Please submit a Request for Quotation (RFQ) for 24CS256-E/P 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/P reliable?
The price and inventory of 24CS256-E/P 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/P is usually 5 days.
3.What payment methods are accepted for 24CS256-E/P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24CS256-E/P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24CS256-E/P?
24CS256-E/P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24CS256-E/P 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/P?
For technical support, including 24CS256-E/P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24CS256-E/P requirements.
6.How does Aetrix verify that 24CS256-E/P is sourced from the original manufacturer or authorized distributors?
All 24CS256-E/P 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/P meets industry standards.
7.What is the process for return or replacement of 24CS256-E/P?
All 24CS256-E/P units undergo pre-shipment inspection (PSI). If there is an issue with 24CS256-E/P, 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/P part is unused and in its original packaging.
Return procedure for 24CS256-E/P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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