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Microchip Technology AT24C256C-XHL-B
- Part No.:
- AT24C256C-XHL-B
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
AT24C256C-XHL-B.pdf
- Description:
- IC EEPROM 256KBIT I2C 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,191
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Product details
Overview
AT24C256C-XHL-B from Microchip Technology is a 256-Kbit I²C-compatible serial EEPROM organized as 32,768 × 8 bits, operating from 1.7V to 5.5V across -40°C to +85°C, with 1 MHz Fast Mode Plus support at 2.5–5.5V and hardware write protection via the WP pin - used for nonvolatile configuration storage in industrial microcontroller systems.
For engineers reviewing the AT24C256C-XHL-B datasheet, AT24C256C-XHL-B pinout, AT24C256C-XHL-B application, or AT24C256C-XHL-B equivalent, key selection criteria include voltage range compatibility (1.7–5.5V), I²C bus speed mode support (Standard/ Fast/ Fast Mode Plus), page write capability (64-byte pages), endurance (1M cycles), and package-specific pin mapping for SOIC-8.
Technical Context
The AT24C256C-XHL-B implements a two-wire I²C interface with Schmitt-triggered, noise-filtered SDA/SCL inputs and open-drain bidirectional data transfer. It supports three I²C speed modes: 100 kHz (1.7–5.5V), 400 kHz (1.7–5.5V), and 1 MHz Fast Mode Plus (2.5–5.5V), with automatic ACK/NACK handshaking and address decoding using A0–A2 pins.
Internally, it features a 512-page × 64-byte memory architecture with self-timed write cycles ≤5 ms, hardware write protection via dedicated WP pin, and power-on reset circuitry ensuring reliable initialization. The device uses internal high-voltage generation for EEPROM programming and includes ESD protection >4 kV.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8 bits) - sufficient for firmware configuration, calibration data, or device identity storage in resource-constrained embedded systems. |
| Interface | I²C (Two-Wire Serial) - enables simple, low-pin-count connection to MCUs without requiring dedicated parallel buses or SPI peripherals. |
| Supply Voltage | 1.7V to 5.5V - supports direct interfacing with 1.8V, 3.3V, and 5V logic domains without level shifters. |
| Write Speed | ≤5 ms max write cycle - enables rapid nonvolatile updates during system runtime without blocking host processor for extended periods. |
| Endurance | 1,000,000 write cycles - ensures long-term reliability in applications requiring frequent parameter logging or field-updatable settings. |
| Data Retention | 100 years at 55°C - guarantees persistent storage integrity over full product lifecycle in industrial environments. |
| Operating Temp | -40°C to +85°C - qualified for use in uncontrolled industrial enclosures, automotive under-hood auxiliary modules, and outdoor IoT edge nodes. |
Pinout & Package
AT24C256C-XHL-B is supplied in an 8-lead SOIC package (XHL suffix per Microchip's ordering code). Pin functions are standardized across SOIC, TSSOP, UDFN, and VFBGA variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Device Address Input | Hardware-selectable bit for I²C slave address; enables up to eight devices on same bus when combined with A1/A2. |
| A1 | Device Address Input | Second hardware address bit; must be hard-wired to GND or VCC for deterministic multi-device addressing. |
| A2 | Device Address Input | Third hardware address bit; floating state internally pulled down, but external biasing recommended for noise immunity. |
| GND | Ground Reference | System return path for VCC and signal references; must be low-impedance connection to minimize ground bounce. |
| SDA | Serial Data Line | Open-drain bidirectional I²C data line; requires external pull-up resistor (≤10 kΩ) and supports wire-OR with other I²C devices. |
| SCL | Serial Clock Line | Input-only I²C clock; rising edge latches input data, falling edge outputs data; requires pull-up for bus idle state. |
| WP | Write-Protect Control | Hardware lock: tied to VCC disables all writes to entire memory array; tied to GND enables normal operation. |
| VCC | Power Supply | Primary supply rail (1.7–5.5V); slew rate limited to ≤0.1 V/µs during power-up to ensure proper POR behavior. |
Key Features
| Feature | Design Value |
|---|---|
| Fast Mode Plus Support | 1 MHz I²C operation at 2.5–5.5V enables faster configuration loading versus standard 400 kHz, reducing boot-time latency. |
| 64-Byte Page Write | Allows partial writes within 64-byte boundaries - improves efficiency when updating small parameter sets without erasing full pages. |
| Schmitt Trigger Inputs | Enhanced noise immunity on SDA/SCL lines reduces false start/stop detection in electrically noisy industrial environments. |
| Ultra-Low Standby Current | 6 µA max at 5.0V - minimizes battery drain in always-on or energy-harvesting sensor nodes between wake events. |
| Hardware Write Protection | Dedicated WP pin provides tamper-resistant locking of critical configuration data without software overhead or vulnerability to firmware bugs. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
Use Scenario: Storing I/O mapping tables, PID tuning parameters, and user-defined alarm thresholds in programmable logic controllers deployed in factory automation cabinets. IC Role / Device Role / Timing Role: Nonvolatile configuration register providing persistent memory for runtime-critical control parameters independent of main MCU power state. Use Value: Enables hot-swappable module replacement without recalibration; retains settings through power loss or firmware updates. | Use Scenario: Holding factory-calibrated sensor offsets, gain coefficients, and regulatory compliance logs in portable diagnostic equipment such as ultrasound probes or infusion pumps. IC Role / Device Role / Timing Role: Secure, long-life data vault for traceable calibration records required by FDA 21 CFR Part 11 and IEC 62304. Use Value: Meets 100-year data retention requirement for medical device lifetime; WP pin prevents accidental overwrite during service mode. |
| Smart Energy Meter Firmware Settings | Automotive Body Control Module NVM |
Use Scenario: Saving tariff schedules, demand-response profiles, and metering constants in ANSI C12.22-compliant smart electricity meters exposed to wide ambient temperature swings. IC Role / Device Role / Timing Role: Industrial-grade EEPROM supporting extended temperature operation (-40°C to +85°C) and high write endurance for daily utility updates. Use Value: Guarantees 1M write cycles for time-of-use billing changes over 10+ years; operates reliably at 1.8V during brownout conditions. | Use Scenario: Storing seat position presets, mirror angles, and lighting profiles in automotive body control units where space and BOM count are constrained. IC Role / Device Role / Timing Role: Compact SOIC-8 serial EEPROM interfacing directly with 3.3V CAN/LIN microcontrollers without voltage translation. Use Value: Reduces PCB area vs. parallel EEPROM; 5.5V tolerance allows shared 5V supply with other analog subsystems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT24C256B-SSHL-T | Same 256-Kbit capacity and I²C interface, but rated only to 400 kHz Fast Mode (no FM+), and specified for 2.5–5.5V operation only. | Lacks 1 MHz support and 1.7V low-voltage operation - unsuitable for battery-powered or mixed-voltage designs requiring sub-2.5V compatibility. | Select AT24C256B-SSHL-T only if FM+ and 1.7V operation are unnecessary and cost is primary constraint. |
| M95256-DRMN6TP/K | 256-Kbit SPI EEPROM (not I²C); operates at 1.8–5.5V; supports 20 MHz SPI clock; no hardware WP pin (software-controlled protection). | Requires SPI peripheral instead of I²C; lacks dedicated write-protect pin - increases firmware complexity for secure configuration locking. | Choose M95256-DRMN6TP/K only when existing design uses SPI bus exclusively and I²C resource is unavailable. |
Compared with AT24C256B-SSHL-T, AT24C256C-XHL-B adds 1 MHz Fast Mode Plus and 1.7V operation for broader voltage flexibility; versus M95256-DRMN6TP/K, it offers native I²C integration and hardware write protection - simplifying layout and security implementation in I²C-based MCU platforms.
Availability
AT24C256C-XHL-B is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, smart metering, and automotive body electronics requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for AT24C256C-XHL-B 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 is a global semiconductor company specializing in microcontrollers, analog devices, FPGAs, and memory solutions, with emphasis on embedded control and connectivity.
The AT24C256C belongs to Microchip's AT24Cxx family of I²C serial EEPROMs, designed specifically for robust, low-power nonvolatile data storage in industrial, automotive, and consumer systems where reliability and voltage flexibility are critical.
FAQ
What is the maximum I²C clock frequency supported by the AT24C256C-XHL-B?
The AT24C256C-XHL-B supports 100 kHz Standard Mode, 400 kHz Fast Mode, and 1 MHz Fast Mode Plus. The 1 MHz operation requires VCC ≥2.5V. At 1.7–2.5V, only Standard and Fast Modes are guaranteed. This enables high-speed configuration loading in systems with adequate supply headroom while maintaining compatibility with legacy 100 kHz buses.
Does the AT24C256C-XHL-B require external pull-up resistors on SDA and SCL lines?
Yes, the AT24C256C-XHL-B requires external pull-up resistors on both SDA and SCL lines because SDA is open-drain and SCL is input-only. Microchip specifies maximum values of 10 kΩ for 100 kHz, 4 kΩ for 400 kHz, and 1.3 kΩ for 1 MHz operation. Proper pull-up sizing ensures timing compliance and noise margin across temperature and voltage ranges.
How does the write-protect (WP) pin function on the AT24C256C-XHL-B?
When the WP pin is driven to VCC, the AT24C256C-XHL-B inhibits all write operations to the entire memory array. When tied to GND, normal read/write access is enabled. If left floating, WP is internally pulled down to GND, but Microchip recommends hard-wiring it to avoid noise-induced protection failures in industrial environments.
What is the memory organization of the AT24C256C-XHL-B?
The AT24C256C-XHL-B organizes its 256 Kbit as 32,768 words × 8 bits, segmented into 512 pages of 64 bytes each. This structure enables efficient 64-byte page writes and supports both random and sequential read modes. Addressing uses a 7-bit I²C slave address with three hardware-configurable bits (A0–A2), allowing up to eight devices on one bus.
Is the AT24C256C-XHL-B compatible with 1.8V microcontrollers?
Yes, the AT24C256C-XHL-B operates from 1.7V to 5.5V and is fully compatible with 1.8V systems. Its I²C interface meets Standard and Fast Mode specifications down to 1.7V, including valid logic thresholds (VIL ≤0.3×VCC, VIH ≥0.7×VCC) and timing margins. No level-shifting circuitry is needed when interfacing with 1.8V MCUs.
AT24C256C-XHL-B 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:
- 550 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
AT24C256C-XHL-B FAQ
1.How can I place an order for AT24C256C-XHL-B through Aetrix?
Please submit a Request for Quotation (RFQ) for AT24C256C-XHL-B 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 AT24C256C-XHL-B reliable?
The price and inventory of AT24C256C-XHL-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT24C256C-XHL-B is usually 5 days.
3.What payment methods are accepted for AT24C256C-XHL-B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT24C256C-XHL-B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT24C256C-XHL-B?
AT24C256C-XHL-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT24C256C-XHL-B 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 AT24C256C-XHL-B?
For technical support, including AT24C256C-XHL-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT24C256C-XHL-B requirements.
6.How does Aetrix verify that AT24C256C-XHL-B is sourced from the original manufacturer or authorized distributors?
All AT24C256C-XHL-B 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 AT24C256C-XHL-B meets industry standards.
7.What is the process for return or replacement of AT24C256C-XHL-B?
All AT24C256C-XHL-B units undergo pre-shipment inspection (PSI). If there is an issue with AT24C256C-XHL-B, 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 AT24C256C-XHL-B part is unused and in its original packaging.
Return procedure for AT24C256C-XHL-B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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