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Microchip Technology AT24C256BW-SH-B
- Part No.:
- AT24C256BW-SH-B
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
AT24C256BW-SH-B.pdf
- Description:
- IC EEPROM 256KBIT I2C 1MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,684
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Product details
Overview
AT24C256BW-SH-B from Microchip Technology (formerly Atmel) is a 256 Kbit (32,768 × 8) two-wire serial EEPROM with 1.8 V to 5.5 V operation, 64-byte page write capability, hardware write protection via WP pin, and 1 MHz I²C compatibility at 2.5 V/5.0 V. It serves as nonvolatile configuration storage in embedded controllers, industrial sensors, and power management systems.
For engineers reviewing the AT24C256BW-SH-B datasheet, AT24C256BW-SH-B pinout, AT24C256BW-SH-B application, or AT24C256BW-SH-B equivalent, key selection criteria include its 1.8 V low-voltage support, 40-year data retention, 1 million write endurance, Schmitt-trigger noise-immune inputs, and 8-lead TSSOP package with NiPdAu lead finish.
Technical Context
The AT24C256BW-SH-B implements a standard I²C-compatible two-wire interface with bidirectional open-drain SDA and edge-triggered SCL, supporting up to eight devices on one bus via A0–A2 address pins. Its internal architecture includes a 15-bit address counter, 512-page memory organization, and integrated high-voltage pump for byte/page programming.
It features hardware write protection (WP pin), software reset recovery, acknowledge polling during write cycles, and Schmitt-trigger filtered inputs for robust operation in electrically noisy environments. The device operates across −40°C to +85°C and supports both byte and page write modes with self-timed 5 ms max write cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8 bits), enabling storage of firmware parameters or calibration data in compact systems |
| Supply Voltage Range | 1.8 V to 5.5 V - supports direct interfacing with 1.8 V logic and legacy 3.3 V/5 V microcontrollers without level shifting |
| I²C Clock Frequency | Up to 1 MHz at 2.5 V/5.0 V; 400 kHz at 1.8 V - balances speed and noise immunity across voltage domains |
| Page Write Capacity | 64 bytes per page - reduces I²C transaction overhead when updating configuration blocks or logging data |
| Write Endurance | 1,000,000 cycles - ensures reliable field updates over product lifetime in telemetry or control applications |
| Data Retention | 40 years at 85°C - guarantees long-term integrity of stored settings without battery backup |
| Input Filtering | Schmitt-trigger inputs with 50–100 ns noise suppression - prevents spurious writes in industrial EMI environments |
Pinout & Package
AT24C256BW-SH-B is packaged in an 8-lead Thin Shrink Small Outline Package (TSSOP), 4.4 mm body width, with NiPdAu lead finish. Pin 1 is marked by a dot at the top-left corner of the package bottom view.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A2 | Hardware Device Address Inputs | Enable up to eight AT24C256BW-SH-B devices on a shared I²C bus; internally pulled down if floating but require external tie-off per design guidance |
| SDA | Serial Data Line | Bidirectional open-drain I²C data line; must be externally pulled up; supports wire-OR with other I²C peripherals |
| SCL | Serial Clock Input | Positive-edge clock input for data-in; negative-edge sampling for data-out; defines I²C timing compliance |
| WP | Write Protect Control | Hardware lock: grounded = write enabled; VCC = full memory write inhibition; floating defaults to GND but requires explicit biasing |
| GND | Ground Reference | Primary return path for all internal circuitry and I/O; must be low-impedance connection to system ground plane |
| VCC | Power Supply | Single-supply input supporting 1.8–5.5 V; decoupling capacitor (0.1 µF) required within 10 mm of pin |
Key Features
| Feature | Design Value |
|---|---|
| Low-Voltage Operation | Functional down to 1.8 V supply - eliminates need for voltage translators in modern ultra-low-power MCU designs |
| Hardware Write Protection | Dedicated WP pin enables fail-safe prevention of accidental writes during power-up or brownout conditions |
| 64-Byte Page Writes | Reduces I²C bus occupancy by up to 94% vs. sequential byte writes - critical for real-time systems with tight timing budgets |
| Noise-Immune Inputs | Schmitt-trigger + RC filtering on SDA/SCL - meets industrial EMC requirements without external components |
| Extended Temperature Range | −40°C to +85°C operation - qualified for deployment in outdoor metering, factory automation, and automotive cabin modules |
Applications
| Smart Energy Meters | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Storing tariff tables, meter calibration constants, and tamper-event logs in utility-grade electricity meters. IC Role / Device Role / Timing Role: Nonvolatile configuration and event storage EEPROM interfaced directly to a 32-bit ARM Cortex-M MCU via I²C. Use Value: 40-year data retention ensures accuracy over meter lifetime; 1.8 V operation enables direct coupling to low-power metrology SoCs. |
Use Scenario: Holding module identification, channel scaling factors, and diagnostic history in DIN-rail mounted programmable logic controller expansion I/O cards. IC Role / Device Role / Timing Role: Persistent parameter storage accessed during boot and runtime by FPGA-based control logic. Use Value: WP pin prevents corruption during hot-swap insertion; Schmitt-trigger inputs reject EMI from adjacent 24 V DC solenoid drivers. |
| Medical Infusion Pumps | Automotive Body Control Modules |
Use Scenario: Saving drug library profiles, dose limits, and usage audit trails in Class II medical infusion devices requiring traceability. IC Role / Device Role / Timing Role: Safety-critical nonvolatile memory for FDA-regulated configuration data, isolated from main processor via optocoupled I²C. Use Value: 1 million write cycles support daily recalibration; 8-lead TSSOP fits constrained PCB space near analog front-end ICs. |
Use Scenario: Storing seat position presets, mirror fold/unfold settings, and lighting configuration in vehicle door modules. IC Role / Device Role / Timing Role: Parameter EEPROM connected to LIN-to-I²C bridge IC, updated only during ignition-off maintenance mode. Use Value: NiPdAu finish ensures solder joint reliability under thermal cycling; 5.5 V max rating accommodates load-dump transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| M24C256-WMN6TP | Same 256 Kbit capacity and I²C interface, but uses 8-lead SOIC-8 (8S1) package and specifies 1.7–5.5 V range; no explicit 1.8 V min guarantee in datasheet | SOIC-8 footprint requires PCB redesign; lacks NiPdAu finish - higher risk of intermetallic growth in high-reliability assemblies | Select only if SOIC-8 is mandatory and 1.8 V operation is not required; verify 1.8 V functionality per unit test |
| BR24G256FJ-3GE2 | Rohm's 256 Kbit I²C EEPROM in 8-lead TSSOP; rated 1.7–5.5 V, 1 MHz @ 2.5–5.5 V, but only 100 kHz @ 1.7 V - slower than AT24C256BW-SH-B at low voltage | Lower 1.7 V min may enable deeper sleep modes, but reduced 100 kHz speed at 1.7 V limits responsiveness in wake-up sequences | Prefer for cost-sensitive consumer designs where 1.8 V performance margin is acceptable; avoid in time-critical industrial firmware updates |
Compared with M24C256-WMN6TP and BR24G256FJ-3GE2, the AT24C256BW-SH-B delivers guaranteed 400 kHz I²C operation at 1.8 V in a NiPdAu-finished TSSOP package - making it uniquely suited for space-constrained, low-voltage, high-reliability industrial and medical applications requiring consistent timing behavior across voltage corners.
Availability
AT24C256BW-SH-B is available at Aetrix Electronics and suitable for smart energy meters, industrial PLC I/O modules, medical infusion pumps, and automotive body control modules requiring stable component supply, long-lifecycle assurance, and RoHS-compliant packaging.
Supply support for AT24C256BW-SH-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 acquired Atmel in 2016 and maintains full technical and manufacturing continuity for the AT24Cxx EEPROM family. The company specializes in microcontrollers, analog, and nonvolatile memory solutions for industrial, automotive, and IoT markets.
The AT24C256BW-SH-B belongs to Microchip's serial EEPROM product line, designed specifically for low-power, multi-voltage embedded systems needing robust, pin-efficient nonvolatile storage with hardware data protection and extended temperature reliability.
FAQ
What is the operating voltage range of the AT24C256BW-SH-B?
The AT24C256BW-SH-B operates from 1.8 V to 5.5 V, with full I²C functionality including 400 kHz clock rate at 1.8 V and 1 MHz at 2.5 V or 5.0 V. This wide range allows direct integration with both modern ultra-low-power MCUs and legacy 3.3 V/5 V systems without level-shifting circuitry. The AT24C256BW-SH-B is characterized and tested across this entire range per its datasheet Rev. 5279C.
Does the AT24C256BW-SH-B support page write operations?
Yes, the AT24C256BW-SH-B supports 64-byte page write mode, allowing up to 64 bytes to be written in a single I²C transaction. Partial page writes are permitted, and the internal address counter automatically increments within the current page boundary. This feature significantly improves write efficiency compared to byte-by-byte programming. The AT24C256BW-SH-B completes each page write in ≤5 ms.
What package type and finish does the AT24C256BW-SH-B use?
The AT24C256BW-SH-B is supplied in an 8-lead Thin Shrink Small Outline Package (TSSOP), designated as 8A2 per Microchip's ordering codes, with NiPdAu (Nickel-Palladium-Gold) lead finish. This finish provides superior solderability, corrosion resistance, and wire-bond compatibility - critical for high-reliability industrial and medical assemblies. The AT24C256BW-SH-B package measures 4.4 mm × 3.0 mm with 0.65 mm lead pitch.
How does the write protect (WP) pin function on the AT24C256BW-SH-B?
On the AT24C256BW-SH-B, the WP pin provides hardware-level write inhibition: when tied to VCC, all memory writes are blocked; when grounded, normal write operations proceed. If left floating, the pin is internally pulled down to GND, but Microchip recommends explicit biasing (e.g., 10 kΩ pull-down) to prevent noise-induced misoperation. This dual-mode protection complements software write-lock commands in the AT24C256BW-SH-B instruction set.
What is the data retention and endurance specification for the AT24C256BW-SH-B?
The AT24C256BW-SH-B guarantees 40 years of data retention at +85°C and 1,000,000 write/erase cycles at 25°C under page-write conditions. These specifications are production-tested and specified in the official datasheet Rev. 5279C. The AT24C256BW-SH-B achieves this reliability through optimized oxide thickness and charge-trapping mechanisms in its floating-gate EEPROM cell structure.
AT24C256BW-SH-B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tube
- 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
AT24C256BW-SH-B FAQ
1.How can I place an order for AT24C256BW-SH-B through Aetrix?
Please submit a Request for Quotation (RFQ) for AT24C256BW-SH-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 AT24C256BW-SH-B reliable?
The price and inventory of AT24C256BW-SH-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT24C256BW-SH-B is usually 5 days.
3.What payment methods are accepted for AT24C256BW-SH-B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT24C256BW-SH-B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT24C256BW-SH-B?
AT24C256BW-SH-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT24C256BW-SH-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 AT24C256BW-SH-B?
For technical support, including AT24C256BW-SH-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT24C256BW-SH-B requirements.
6.How does Aetrix verify that AT24C256BW-SH-B is sourced from the original manufacturer or authorized distributors?
All AT24C256BW-SH-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 AT24C256BW-SH-B meets industry standards.
7.What is the process for return or replacement of AT24C256BW-SH-B?
All AT24C256BW-SH-B units undergo pre-shipment inspection (PSI). If there is an issue with AT24C256BW-SH-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 AT24C256BW-SH-B part is unused and in its original packaging.
Return procedure for AT24C256BW-SH-B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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