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Microchip Technology AT24C256BN-SH-T
- Part No.:
- AT24C256BN-SH-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
AT24C256BN-SH-T.pdf
- Description:
- IC EEPROM 256KBIT I2C 1MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,089
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Product details
Overview
AT24C256BN-SH-T from Microchip Technology (formerly Atmel) is a 256 Kbit I²C-compatible serial EEPROM organized as 32,768 × 8 bits, operating from 1.8 V to 5.5 V, featuring hardware write protection via WP pin and 64-byte page write capability. It supports up to 1 MHz clock frequency at 5.0 V/2.7 V/2.5 V and 400 kHz at 1.8 V, and is used in industrial sensor calibration storage and embedded system configuration retention.
For engineers reviewing the AT24C256BN-SH-T datasheet, AT24C256BN-SH-T pinout, AT24C256BN-SH-T application, or AT24C256BN-SH-T equivalent, key selection considerations include its 1.8–5.5 V supply range, 1 million write endurance, 40-year data retention, 8-lead TSSOP package with NiPdAu lead finish, and compatibility with standard two-wire bus protocols across multiple voltage domains.
Technical Context
The AT24C256BN-SH-T implements a two-wire serial interface with Schmitt-triggered, noise-filtered SDA and SCL inputs, supporting bidirectional data transfer and acknowledge polling during internal write cycles. Its address decoding uses three hardwired A0–A2 pins enabling up to eight devices on a shared bus.
Internally, it features a 512-page × 64-byte memory architecture with automatic address incrementing within pages, self-timed 5 ms max write cycles, and hardware/software write protection via the WP pin-internally pulled low when floating but requiring external bias per design guidance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8), sufficient for firmware parameter tables or device-specific calibration data sets |
| Supply Voltage Range | 1.8 V to 5.5 V - enables direct interfacing with 1.8 V logic, 3.3 V microcontrollers, and legacy 5 V systems without level shifting |
| Interface Speed | Up to 1 MHz at ≥2.5 V; 400 kHz at 1.8 V - balances speed and noise immunity across voltage grades |
| Write Endurance | 1,000,000 cycles - supports frequent recalibration or logging in industrial monitoring applications |
| Data Retention | 40 years at 25 °C - ensures long-term reliability for unattended or maintenance-free deployments |
| Page Write Capacity | 64 bytes per page - reduces I²C transaction overhead versus byte writes, improving update efficiency |
| Operating Temperature | −40 °C to +85 °C - qualified for industrial ambient environments including factory automation and outdoor metering |
Pinout & Package
AT24C256BN-SH-T is supplied in an 8-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, body size 4.4 mm × 3.0 mm × 1.2 mm max, with NiPdAu lead finish for enhanced solderability and corrosion resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A2 | Hardware Device Address Inputs | Enable up to eight AT24C256BN-SH-T devices on one I²C bus; must be externally tied to VCC or GND - floating pins default low but are discouraged due to capacitive coupling risk |
| SDA | Serial Data Line | Bidirectional open-drain I/O; requires external pull-up resistor; wire-ORable with other I²C devices on same bus |
| SCL | Serial Clock Input | Positive-edge sampled input controlling data timing; negative-edge clocks data out; Schmitt-triggered for noise immunity |
| WP | Write Protect Control | Active-high hardware lock: tied to VCC disables all writes; tied to GND enables full read/write access |
| GND | Ground Reference | Primary return path for VCC and signal currents; must be low-impedance connection to avoid noise coupling into SDA/SCL |
| VCC | Power Supply | Accepts 1.8–5.5 V; decoupling capacitor (0.1 µF ceramic) required near pin to suppress switching transients |
Key Features
| Feature | Design Value |
|---|---|
| Low-voltage operation | Functional down to 1.8 V supply - eliminates need for separate 3.3 V or 5 V rails in battery-powered or energy-harvesting designs |
| Noise-suppressed inputs | Schmitt-trigger + filtering on SDA/SCL - rejects >100 ns glitches, enabling robust operation in electrically noisy industrial enclosures |
| Hardware write protection | WP pin directly inhibits all write commands when high - prevents accidental overwrites during power transitions or firmware faults |
| Page write mode | 64-byte burst writes reduce I²C bus occupancy by ~94% vs. sequential byte writes - critical for real-time systems with tight timing budgets |
| Self-timed write cycle | Internal 5 ms max erase/write completion - relieves host MCU of precise timing control; supports ACK polling for non-blocking operation |
Applications
| Industrial Sensor Calibration Storage | Embedded System Configuration Retention |
|---|---|
Use Scenario: Storing temperature, pressure, or humidity sensor offset/gain coefficients updated during factory calibration or field recalibration. IC Role / Device Role / Timing Role: Nonvolatile parameter repository accessed via I²C during boot or on-demand; WP pin secured during normal operation. Use Value: Enables traceable, field-updatable calibration without requiring reprogramming tools or firmware updates - reducing service cost and downtime. |
Use Scenario: Holding user-configurable settings (e.g., display brightness, network IP, alarm thresholds) across power cycles in medical monitors or HVAC controllers. IC Role / Device Role / Timing Role: Persistent configuration store written infrequently but read at every startup; leverages 40-year retention for product lifetime compliance. Use Value: Eliminates need for battery-backed SRAM, simplifying BOM and avoiding end-of-life battery replacement in sealed equipment. |
| Smart Meter Firmware Parameter Tables | POS Terminal Transaction Log Buffer |
Use Scenario: Storing tariff schedules, billing algorithms, and regulatory compliance flags in electricity/water meters deployed for >10 years. IC Role / Device Role / Timing Role: Read-mostly memory with occasional secure updates; WP pin controlled by secure bootloader to prevent unauthorized writes. Use Value: Meets IEC 62056 and ANSI C12.22 requirements for tamper-resistant, long-life data storage in revenue-critical infrastructure. |
Use Scenario: Capturing last N transaction records (e.g., card swipe timestamps, amounts) during brief power loss in retail point-of-sale terminals. IC Role / Device Role / Timing Role: High-endurance write buffer using page mode to minimize I²C bus contention during peak transaction periods. Use Value: Guarantees audit trail integrity even during brownout events - satisfies PCI DSS requirement for nonvolatile transaction logging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| M24256-BWMN6TP | Same 256 Kbit capacity, 1.8–5.5 V, but uses different I²C address mapping (A0–A1 only); 100 kHz/400 kHz/1 MHz speeds identical | Requires minor firmware adjustment for device addressing; pinout identical in TSSOP-8 | Select if sourcing from STMicroelectronics preferred; verify A2 handling in existing I²C stack |
| CAT24C256HU4I-GT3 | Identical 256 Kbit × 8 organization, 1.8–5.5 V, 1 MHz max, but rated for −40 °C to +125 °C extended temp range | Suitable for under-hood automotive or high-temp industrial environments where AT24C256BN-SH-T's 85 °C limit is insufficient | Choose for extended temperature applications; otherwise functionally interchangeable in industrial designs |
Compared with M24256-BWMN6TP and CAT24C256HU4I-GT3, the AT24C256BN-SH-T offers identical core functionality and TSSOP-8 packaging but differs in device addressing flexibility and temperature qualification - making it optimal for cost-sensitive industrial designs operating within standard industrial temperature bounds.
Availability
AT24C256BN-SH-T is available at Aetrix Electronics and suitable for industrial sensor calibration storage, embedded system configuration retention, and smart meter firmware parameter tables requiring stable component supply and long-term lifecycle support.
Supply support for AT24C256BN-SH-T 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 acquired Atmel in 2016 and now manufactures and supports the AT24C256BN-SH-T as part of its broad serial EEPROM portfolio, emphasizing reliability, longevity, and industrial-grade qualification.
The AT24C256BN-SH-T belongs to Microchip's AT24Cxx family of I²C-compatible EEPROMs, designed specifically for low-power, multi-voltage embedded systems needing robust, field-updatable nonvolatile storage in space-constrained packages.
FAQ
What is the maximum I²C clock frequency supported by the AT24C256BN-SH-T?
The AT24C256BN-SH-T supports up to 1 MHz I²C clock frequency when operated at VCC = 2.5 V, 2.7 V, or 5.0 V. At 1.8 V, the maximum clock frequency is 400 kHz. These values are specified in Table 3-3 of the datasheet and reflect guaranteed AC timing performance across the industrial temperature range (−40 °C to +85 °C). The AT24C256BN-SH-T maintains full compatibility with standard I²C protocol timing requirements at both speed grades.
Does the AT24C256BN-SH-T require external pull-up resistors on SDA and SCL lines?
Yes, the AT24C256BN-SH-T requires external pull-up resistors on both SDA and SCL lines because these pins are open-drain outputs. The recommended pull-up value is 1.3 kΩ for 2.5 V or 5.5 V operation and 10 kΩ for 1.8 V operation, as defined in the AC measurement conditions section of the datasheet. Without proper pull-ups, the AT24C256BN-SH-T cannot drive valid logic high levels on the I²C bus, resulting in communication failure.
How does the write protect (WP) pin function on the AT24C256BN-SH-T?
The WP pin on the AT24C256BN-SH-T is an active-high hardware write protection input. When WP is tied to VCC, all write operations-including byte, page, and sequential writes-are inhibited, though reads remain fully functional. When WP is tied to GND, normal read/write access is enabled. The AT24C256BN-SH-T internally pulls WP low if left floating, but Atmel explicitly recommends hardwiring WP to a known state to prevent unintended behavior due to capacitive coupling.
What package type and lead finish does the AT24C256BN-SH-T use?
The AT24C256BN-SH-T is packaged in an 8-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, with NiPdAu (Nickel-Palladium-Gold) lead finish. This finish provides superior solderability, corrosion resistance, and wire-bond compatibility compared to standard SnPb or pure matte tin finishes, and is explicitly confirmed in the ordering code "AT24C256BN-SH-T(2) (NiPdAu Lead Finish)" in the source documentation.
Can the AT24C256BN-SH-T be used in a 1.8 V-only system without level shifting?
Yes, the AT24C256BN-SH-T is fully compatible with 1.8 V-only systems. Its absolute minimum supply voltage is 1.8 V, and it guarantees 400 kHz I²C operation, 1 µA standby current, and full read/write functionality at this voltage. All DC and AC specifications-including VOL, VIH, VIL, and tSU.DAT-are characterized down to 1.8 V, eliminating the need for voltage translation when interfacing with 1.8 V microcontrollers or FPGAs. The AT24C256BN-SH-T is explicitly designated as a 1.8 V option in the ordering table.
AT24C256BN-SH-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 550 ns
- Voltage - Supply:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
AT24C256BN-SH-T FAQ
1.How can I place an order for AT24C256BN-SH-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT24C256BN-SH-T 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 AT24C256BN-SH-T reliable?
The price and inventory of AT24C256BN-SH-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT24C256BN-SH-T is usually 5 days.
3.What payment methods are accepted for AT24C256BN-SH-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT24C256BN-SH-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT24C256BN-SH-T?
AT24C256BN-SH-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT24C256BN-SH-T 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 AT24C256BN-SH-T?
For technical support, including AT24C256BN-SH-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT24C256BN-SH-T requirements.
6.How does Aetrix verify that AT24C256BN-SH-T is sourced from the original manufacturer or authorized distributors?
All AT24C256BN-SH-T 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 AT24C256BN-SH-T meets industry standards.
7.What is the process for return or replacement of AT24C256BN-SH-T?
All AT24C256BN-SH-T units undergo pre-shipment inspection (PSI). If there is an issue with AT24C256BN-SH-T, 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 AT24C256BN-SH-T part is unused and in its original packaging.
Return procedure for AT24C256BN-SH-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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