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Microchip Technology 24CS256T-I/ST
- Part No.:
- 24CS256T-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
24CS256T-I/ST.pdf
- Description:
- IC EEPROM 256KBIT I2C 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,893
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Product details
Overview
24CS256T-I/ST 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 units for firmware parameter storage.
For engineers reviewing the 24CS256T-I/ST datasheet, 24CS256T-I/ST pinout, 24CS256T-I/ST application, or 24CS256T-I/ST equivalent, key selection criteria include I²C speed compatibility (100 kHz–3.4 MHz), 1.7V–5.5V supply range, industrial temperature rating (–40°C to +85°C), WP pin behavior, and Security register access protocol for secure device identification.
Technical Context
The 24CS256T-I/ST 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 (0800h–080Fh) and programmable ID page (0840h–087Fh).
Write protection operates via dual modes: hardware-based full-array lock using the WP pin, or enhanced software-configurable zone protection (eight independent 32-Kbit zones) controlled by a permanently lockable Configuration register. Built-in ECC corrects one bit per four-byte readout and latches error state in the ECS bit.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8-bit), organized in 512 pages of 64 bytes - enables efficient block-level firmware updates without full-erase overhead. |
| I²C Speed Support | Up to 3.4 MHz (High-Speed mode), plus 1 MHz / 400 kHz / 100 kHz - supports real-time configuration loading in fast-boot embedded systems. |
| Write Cycle Time | ≤5 ms max (self-timed), no external delay required - simplifies host firmware timing and eliminates need for polling or timeout loops. |
| Operating Voltage | 1.7V to 5.5V - interoperable with 1.8V logic microcontrollers and legacy 5V systems without level-shifting. |
| Temperature Range | Industrial: –40°C to +85°C - qualified for under-hood and dashboard-mounted automotive electronics. |
| Data Retention | >200 years at 55°C - ensures long-term calibration data integrity across vehicle lifetime. |
| Endurance | 1,000,000 write cycles - supports frequent logging or adaptive tuning applications like battery management systems. |
Pinout & Package
24CS256T-I/ST is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with gull-wing leads, RoHS-compliant, surface-mountable, and rated for industrial temperature operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Device Address Input | Hardware-selectable LSB of 3-bit client address; ties to VSS or VCC to enable up to eight devices on same I²C bus. |
| A1 | Device Address Input | Middle bit of hardware client address; determines unique 7-bit I²C address when combined with A0/A2. |
| A2 | Device Address Input | MSB of hardware client address; must be hard-wired (not floating) to ensure deterministic bus addressing. |
| VSS | Ground Reference | Primary return path for all internal circuitry and I/O; requires low-impedance connection to system GND plane. |
| SDA | Serial Data Line | Open-drain bidirectional I²C data line; requires external pull-up resistor (e.g., 2 kΩ for 1 MHz, 330 Ω for 3.4 MHz). |
| SCL | Serial Clock Input | Input-only I²C clock line; driven by host controller; slope-controlled to reduce EMI and ground bounce. |
| WP | Write-Protect Control | Active-high hardware lock: tied to VCC disables all writes to main array and Security register; tied to VSS enables full write access. |
| VCC | Power Supply | Single-supply input (1.7–5.5V); powers EEPROM core, I/O buffers, and internal ECC logic; decoupling capacitor required. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-Programmed 128-Bit Serial Number | Uniquely identifies each unit across CS-series EEPROMs - eliminates manufacturing serialization effort and enables traceability in Tier-1 automotive supply chains. |
| User-Programmable & Lockable 64-Byte ID Page | Stores immutable device-specific keys or calibration data; once locked via software sequence, prevents tampering or overwrite in field-deployed units. |
| Built-In Error Correction Code (ECC) | Corrects single-bit errors per 4-byte read; ECS latch signals correction event - enhances reliability in electrically noisy automotive environments. |
| Enhanced Software Write Protection | Configures eight independent 32-Kbit zones for granular protection; Configuration register can be permanently locked - replaces mechanical WP pin dependency for flexible security policies. |
| I²C Manufacturer Identification Function | Returns unique 24-bit ID on command - allows runtime verification of genuine Microchip device and detection of counterfeit parts in production test. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing door lock actuation history, mirror position presets, and lighting profiles across ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile parameter retention IC with guaranteed 200-year data retention and AEC-Q100 qualification for under-dash mounting. Use Value: Eliminates need for backup battery or supercapacitor; WP pin and ECC ensure integrity of safety-critical settings during voltage transients. |
Use Scenario: Holding ladder logic configuration, I/O mapping, and calibration offsets in modular automation controllers. IC Role / Device Role / Timing Role: I²C-configurable memory peripheral interfacing with ARM Cortex-M7 host MCU over 1 MHz bus. Use Value: 3.4 MHz High-Speed mode reduces configuration load time by >70% vs. legacy 400 kHz EEPROMs; 1.7V min VCC supports wide-input DC-DC rails. |
| Medical Infusion Pump Calibration | Smart Energy Meter Firmware Parameters |
Use Scenario: Archiving dose calibration coefficients, maintenance logs, and operator audit trails in Class II medical devices. IC Role / Device Role / Timing Role: Secure, tamper-evident storage element with lockable ID page for regulatory compliance (IEC 62304). Use Value: Factory serial number + programmable ID page satisfies UDI requirements; ECC prevents silent data corruption in long-term deployments. |
Use Scenario: Storing tariff schedules, metering constants, and communication credentials in ANSI C12.22-compliant smart meters. IC Role / Device Role / Timing Role: Dual-mode write-protected memory supporting both hardware (WP pin) and software (Configuration register) security policies. Use Value: Enhanced software protection allows field-upgradable zone locks without PCB redesign; 5.5V max VCC tolerates AC-line surge events. |
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; no ECC; max I²C speed 1 MHz; 1.7–5.5V. | Lacks hardware-assisted device identity and error resilience - unsuitable for automotive or medical use cases requiring traceability or fault tolerance. | Select only for cost-sensitive consumer applications where serial number and ECC are nonessential. |
| 24AA256-I/SN | Same pinout and basic function; no Security register; no ECC; no High-Speed mode (max 400 kHz); 1.8–5.5V. | Lower speed and missing security features limit use to legacy industrial controls with slow I²C buses and no anti-counterfeit requirements. | Choose only if backward compatibility with existing 24AA256 designs is mandatory and 3.4 MHz operation is unnecessary. |
Compared with AT24C256C-SSHL-T and 24AA256-I/SN, the 24CS256T-I/ST delivers differentiated value through integrated security (serial number + lockable ID), ECC-driven reliability, and 3.4 MHz throughput - making it the sole option among these three qualified for AEC-Q100 automotive systems requiring both performance and trust.
Availability
24CS256T-I/ST 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, long-lifecycle support, and AEC-Q100 compliance.
Supply support for 24CS256T-I/ST 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 24CS256T-I/ST belongs to Microchip's CS-series serial EEPROM family, engineered specifically for automotive, industrial, and medical applications demanding enhanced security, high-speed I²C, and extended reliability beyond standard EEPROM offerings.
FAQ
What is the package type and lead finish of the 24CS256T-I/ST?
The 24CS256T-I/ST uses an 8-lead SOIC package (SOIJ variant per datasheet DS20005998D) with gull-wing leads and matte tin (Sn) lead finish, RoHS-compliant and compatible with standard reflow soldering profiles for industrial and automotive assembly lines.
Does the 24CS256T-I/ST support I²C High-Speed mode, and what conditions apply?
Yes, the 24CS256T-I/ST supports I²C High-Speed mode up to 3.4 MHz, but only when VCC is ≥2.5V and ambient temperature is within the Industrial range (–40°C to +85°C). The HS mode must be explicitly enabled via the High-Speed Mode host code (00001XXx) in the device address byte.
How is the 128-bit serial number accessed in the 24CS256T-I/ST?
The 128-bit serial number resides in the read-only portion of the Security register at addresses 0800h–080Fh. Access requires sending the Security register device address (1011 A2 A1 A0 R/W) followed by word address bytes with A15=0 and A11–A10=10b, then reading 16 bytes sequentially.
Can the Configuration register of the 24CS256T-I/ST be unlocked after being permanently locked?
No - once the Configuration register is permanently locked via the software lock sequence, it becomes read-only for the life of the 24CS256T-I/ST. This irreversible lock ensures that write protection settings and ECC configuration remain tamper-proof in deployed systems.
What is the maximum number of 24CS256T-I/ST devices that can share a single I²C bus?
Up to eight 24CS256T-I/ST devices can operate on the same I²C bus, enabled by the three hardware address pins (A0, A1, A2), each configurable as logic high or low to generate unique 7-bit client addresses within the 1010xxx binary prefix range.
24CS256T-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- 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:
- 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-TSSOP
24CS256T-I/ST FAQ
1.How can I place an order for 24CS256T-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 24CS256T-I/ST 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/ST reliable?
The price and inventory of 24CS256T-I/ST 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/ST is usually 5 days.
3.What payment methods are accepted for 24CS256T-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24CS256T-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24CS256T-I/ST?
24CS256T-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24CS256T-I/ST 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/ST?
For technical support, including 24CS256T-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24CS256T-I/ST requirements.
6.How does Aetrix verify that 24CS256T-I/ST is sourced from the original manufacturer or authorized distributors?
All 24CS256T-I/ST 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/ST meets industry standards.
7.What is the process for return or replacement of 24CS256T-I/ST?
All 24CS256T-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 24CS256T-I/ST, 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/ST part is unused and in its original packaging.
Return procedure for 24CS256T-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
24CS256T-I/ST Tags
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