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Microchip Technology 24FC256-I/ST
- Part No.:
- 24FC256-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
24FC256-I/ST.pdf
- Description:
- IC EEPROM 256KBIT I2C 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:811
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Product details
Overview
24FC256-I/ST from Microchip Technology is a 256-Kbit (32K × 8) I²C-compatible serial EEPROM with 1.7V–5.5V single-supply operation, 1 MHz maximum clock frequency at VCC ≥ 2.5V, and industrial temperature range (–40°C to +85°C). It features a 64-byte page write buffer, hardware write-protection via WP pin, and Schmitt-trigger inputs for noise immunity-used in embedded system configuration storage, sensor calibration data retention, and firmware parameter backup.
For engineers reviewing the 24FC256-I/ST datasheet, 24FC256-I/ST pinout, 24FC256-I/ST application, or 24FC256-I/ST equivalent, key selection criteria include its 1 MHz I²C speed capability (vs. 400 kHz for 24AA256), 1 µA standby current, 5 ms max page write time, and SOIC-8 package compatibility with legacy board layouts.
Technical Context
The 24FC256-I/ST implements a two-wire I²C interface with programmable device addressing via A0–A2 pins, supporting up to eight devices on one bus. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and memory control logic enabling self-timed erase/write cycles without external timing components.
It uses open-drain SDA/SCL with integrated Schmitt triggers and slope control to suppress ground bounce and noise spikes. Write protection is implemented through a dedicated WP input sampled at the Stop bit, and acknowledge polling is supported to detect write cycle completion without fixed delays.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8) - supports full system configuration storage for microcontrollers with limited internal NVM |
| I²C Clock Frequency | Up to 1 MHz at VCC ≥ 2.5V - enables faster parameter updates vs. 400 kHz alternatives, reducing host MCU wait time |
| Page Write Buffer | 64 bytes - allows efficient bulk writes without repeated address setup, minimizing I²C transaction overhead |
| Write Cycle Time | ≤ 5 ms per byte or page - deterministic timing simplifies host firmware timeout handling |
| Supply Voltage Range | 1.7V to 5.5V - interoperable with 1.8V, 3.3V, and 5V systems without level shifters |
| Standby Current | 1 µA max (I-temp.) - critical for battery-powered devices requiring multi-year data retention |
| Data Retention | >200 years - ensures long-term reliability in unattended industrial deployments |
Pinout & Package
24FC256-I/ST is supplied in an 8-lead SOIC package (ST suffix), with standard 150-mil body width and gull-wing leads. Pin 1 is marked by a beveled corner or notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Chip Address Input | User-configurable LSB of 3-bit device address; tied high/low to select one of eight possible I²C addresses on shared bus |
| A1 | Chip Address Input | Middle bit of device address; enables cascading multiple 24FC256-I/ST units without address conflict |
| A2 | Chip Address Input | MSB of device address; required for expanding contiguous memory space across up to eight devices (2 Mbit total) |
| VSS | Ground Reference | Primary return path for all internal circuitry and I/O; must be low-impedance connection to minimize noise coupling |
| SDA | Serial Data I/O | Open-drain bidirectional line; requires external pull-up resistor (2 kΩ typical for 1 MHz); carries address, command, and data |
| SCL | Serial Clock Input | Input-only clock line synchronized to host controller; rising edge samples data, falling edge allows data change |
| WP | Write-Protect Control | Active-high hardware lock; when tied to VCC, prevents all write/erase operations while permitting unlimited reads |
| VCC | Power Supply | Single 1.7–5.5V supply powering EEPROM array, interface logic, and charge pump; no separate VPP required |
Key Features
| Feature | Design Value |
|---|---|
| 1 MHz I²C Compatibility | Enables 2.5× faster write throughput than 400 kHz EEPROMs, reducing host MCU blocking time during configuration updates |
| Schmitt Trigger Inputs | Provides 50 ns spike suppression and 0.05 VCC hysteresis on SDA/SCL, eliminating need for external RC filtering in noisy industrial environments |
| Hardware Write Protection | WP pin disables writes at silicon level-prevents accidental firmware corruption during power-up/down or ESD events |
| 1 Million Erase/Write Cycles | Guarantees >10 years of daily reconfiguration in logging or calibration applications (365 cycles/year) |
| 64-Byte Page Write Buffer | Allows burst writes of up to 64 bytes with single address setup, cutting I²C bus transactions by up to 98% vs. byte-write mode |
Applications
| Industrial Sensor Node | Medical Device Calibration |
|---|---|
Use Scenario: Remote temperature/humidity sensor node stores calibration coefficients, last-measured values, and fault logs between wake cycles. IC Role / Device Role / Timing Role: Nonvolatile configuration storage with infrequent writes and frequent reads; retains data during 10-year battery life. Use Value: 1 µA standby current extends battery life; 1.7V operation ensures functionality down to end-of-life battery voltage. | Use Scenario: Portable blood glucose meter stores user-specific calibration curves, usage history, and regulatory audit logs. IC Role / Device Role / Timing Role: Secure, tamper-resistant parameter storage; WP pin prevents unauthorized recalibration during field use. Use Value: Hardware write-protection meets IEC 62304 safety requirements; >200-year data retention satisfies medical device archival mandates. |
| Smart Energy Meter | Automotive Body Control Module |
Use Scenario: Electricity meter records tariff schedules, billing intervals, and tamper-event timestamps across 15+ year service life. IC Role / Device Role / Timing Role: High-endurance data logger; withstands >10,000 write cycles/year over lifetime. Use Value: 1 million write cycles guarantee >100 years of operation at worst-case duty cycle; industrial temp rating covers outdoor enclosure extremes. | Use Scenario: BCM stores seat/mirror position presets, lighting profiles, and diagnostic trouble codes (DTCs) across ignition cycles. IC Role / Device Role / Timing Role: Fast-access configuration memory interfaced directly to 32-bit MCU via 1 MHz I²C. Use Value: 1 MHz clock support reduces MCU wait states; SOIC-8 footprint matches legacy automotive PCB designs. |
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/ST | Max I²C clock = 400 kHz; same 1.7–5.5V range and SOIC-8 package | Limited to lower-speed systems where 1 MHz timing margin is unnecessary | Select when cost sensitivity outweighs speed requirement; identical pinout and software interface |
| AT24C256-10PU-2.7 | Max I²C clock = 1 MHz; 2.7–5.5V supply; PDIP-8 package only | Not suitable for surface-mount production; lacks 1.7V operation for ultra-low-power designs | Choose only for through-hole prototyping or legacy PDIP-based systems requiring same speed |
Compared with 24AA256-I/ST, the 24FC256-I/ST delivers 2.5× faster I²C throughput and maintains full 1.7V compatibility, while AT24C256-10PU-2.7 offers equivalent speed but sacrifices low-voltage operation and modern packaging.
Availability
24FC256-I/ST is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, and smart energy metering requiring stable component supply across extended product lifecycles.
Supply support for 24FC256-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, serving industrial, automotive, and consumer markets with high-reliability semiconductor products.
The 24FC256 belongs to Microchip's 24XX256 family of I²C EEPROMs, designed specifically for low-power, high-endurance nonvolatile data storage in resource-constrained embedded systems.
FAQ
What is the maximum I²C clock frequency supported by the 24FC256-I/ST?
The 24FC256-I/ST supports up to 1 MHz I²C clock frequency when VCC is 2.5V or higher. At VCC < 2.5V, the maximum clock rate drops to 400 kHz. This dual-speed capability allows seamless integration into both legacy 400 kHz systems and newer high-throughput designs without changing the 24FC256-I/ST part number.
Does the 24FC256-I/ST require an external high-voltage programming supply?
No, the 24FC256-I/ST does not require an external high-voltage supply. It integrates an on-chip charge pump that generates the necessary programming voltage from the standard 1.7–5.5V VCC rail. This eliminates external components and simplifies PCB layout-critical for space-constrained applications using the 24FC256-I/ST.
How many devices can be connected to the same I²C bus using the 24FC256-I/ST?
Up to eight 24FC256-I/ST devices can be connected to a single I²C bus using the A0, A1, and A2 address pins to configure unique 3-bit device addresses. Each pin must be hard-wired to VSS or VCC; floating connections are not permitted. The 24FC256-I/ST's SOIC-8 package exposes all three address pins for full address flexibility.
What is the function of the WP pin on the 24FC256-I/ST?
The WP (Write-Protect) pin on the 24FC256-I/ST is a hardware-level enable/disable control for all write and erase operations. When WP is tied to VCC, writes are inhibited while reads remain fully functional. When WP is tied to VSS, normal read/write operation is enabled. The pin is sampled at the Stop bit of each write command, making it effective for preventing accidental writes during power transitions.
Is the 24FC256-I/ST compatible with standard I²C protocol implementations?
Yes, the 24FC256-I/ST is fully compliant with the standard I²C protocol, including Start/Stop conditions, 7-bit addressing (with 4-bit '1010' prefix and 3-bit chip select), ACK/NACK signaling, and clock stretching support. It responds to standard I²C commands without requiring custom drivers-ensuring drop-in compatibility with existing MCU I²C peripherals and software stacks using the 24FC256-I/ST.
24FC256-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- 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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
24FC256-I/ST FAQ
1.How can I place an order for 24FC256-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 24FC256-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 24FC256-I/ST reliable?
The price and inventory of 24FC256-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 24FC256-I/ST is usually 5 days.
3.What payment methods are accepted for 24FC256-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24FC256-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24FC256-I/ST?
24FC256-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24FC256-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 24FC256-I/ST?
For technical support, including 24FC256-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24FC256-I/ST requirements.
6.How does Aetrix verify that 24FC256-I/ST is sourced from the original manufacturer or authorized distributors?
All 24FC256-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 24FC256-I/ST meets industry standards.
7.What is the process for return or replacement of 24FC256-I/ST?
All 24FC256-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 24FC256-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 24FC256-I/ST part is unused and in its original packaging.
Return procedure for 24FC256-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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