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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Microchip Technology AT24C256C-MAPD-T

Name: AT24C256C-MAPD-T
Brand: Microchip Technology
SKU: AT24C256C-MAPD-T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AT24C256C-MAPD-T

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-UFDFN Exposed Pad

Datasheet:: AT24C256C-MAPD-T.pdf

Description:: IC EEPROM 256KBIT I2C 8UDFN

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Product details

Overview

AT24C256C-MAPD-T from Microchip Technology is a 256-Kbit (32,768 × 8) automotive-grade I²C serial EEPROM with AEC-Q100 Grade 1 qualification, operating from 2.5V to 5.5V over –40°C to +125°C, featuring 64-byte page write, 1,000,000 write endurance, and hardware write protection via WP pin - used for calibration storage in engine control units and ADAS sensor modules.

For engineers reviewing the AT24C256C-MAPD-T datasheet, AT24C256C-MAPD-T pinout, AT24C256C-MAPD-T application, or AT24C256C-MAPD-T equivalent, key selection criteria include I²C Fast Mode (400 kHz) timing compliance, Grade 1 temperature support, 8-lead SOIC package compatibility, and hardware write-protection implementation in safety-critical automotive subsystems.

Technical Context

The AT24C256C-MAPD-T implements a two-wire I²C slave interface with Schmitt-triggered, noise-filtered SDA/SCL inputs and open-drain bidirectional data transfer. It uses internal high-voltage generation for EEPROM cell programming and integrates a Power-on Reset (POR) circuit with 100 µs tPUP delay after stable VCC.

Memory is organized as 512 pages of 64 bytes each, supporting byte-write, page-write (with partial-page capability), current-address read, random read, and sequential read modes. Device addressing uses hardwired A0–A2 pins (internally pulled down if floating) to support up to eight devices on one bus with 7-bit address format (1010xxxR/W).

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	256 Kbit (32,768 × 8 bits), mapped to 512 × 64-byte pages - enables efficient firmware parameter logging in ECUs without external address latching.
Interface	I²C-compatible two-wire bus, supports Standard Mode (100 kHz) and Fast Mode (400 kHz) - compatible with most microcontroller I²C peripherals without protocol translation.
Supply Voltage	2.5V to 5.5V (Grade 1) - operates across automotive battery range (e.g., 3.3V MCU domains and 5V legacy systems) without level-shifting.
Temperature Range	–40°C to +125°C (AEC-Q100 Grade 1) - qualified for under-hood deployment in powertrain and chassis control modules.
Write Endurance	1,000,000 cycles - supports frequent recalibration updates in adaptive suspension or emissions learning algorithms.
Data Retention	100 years at 55°C - ensures long-term reliability of stored vehicle configuration and diagnostic history across product lifetime.
Active Current	≤3.0 mA max at 5.0V/400 kHz write - minimizes impact on low-power sleep modes during infrequent write operations.
Standby Current	≤6.0 µA at 5.0V - meets stringent automotive quiescent current budgets for always-on modules.

Pinout & Package

AT24C256C-MAPD-T is supplied in an 8-lead SOIC package (3.9 mm × 4.9 mm, 1.27 mm pitch), pin-compatible with industry-standard 8-pin EEPROM footprints and suitable for reflow assembly.

Pin/Terminal	Circuit Role	Design Meaning
A0	Device Address Input	Hardwired logic level sets bit 3 of 7-bit I²C slave address; internally pulled down if floating - enables multi-device bus addressing up to 8 units.
A1	Device Address Input	Hardwired logic level sets bit 2 of 7-bit I²C slave address; internally pulled down if floating - used with A0/A2 to configure unique device ID on shared bus.
A2	Device Address Input	Hardwired logic level sets bit 1 of 7-bit I²C slave address; internally pulled down if floating - required for system-level EEPROM expansion without software remapping.
GND	Ground Reference	System ground return path for VCC and I/O; must be low-impedance connection to minimize noise coupling into sensitive EEPROM read/write paths.
SDA	Serial Data Line	Open-drain bidirectional I²C data line; requires external pull-up resistor ≤10 kΩ - interfaces directly with MCU I²C peripheral with no additional buffering.
SCL	Serial Clock Line	Input-only I²C clock line; must be pulled high externally - synchronizes all data transfers and supports both 100 kHz and 400 kHz timing windows.
WP	Hardware Write-Protect	Logic-high input disables all write operations to entire memory array - provides fail-safe protection against unintended firmware corruption during ECU boot or reset sequences.
VCC	Power Supply	Primary supply input (2.5–5.5V); powers internal charge pump and logic - must ramp monotonically at ≤0.1 V/µs to ensure reliable POR behavior.

Key Features

Feature	Design Value
Automotive AEC-Q100 Grade 1 Qualification	Validated for operation from –40°C to +125°C with full electrical testing per stress test conditions - eliminates need for derating or additional thermal validation in powertrain applications.
64-Byte Page Write with Partial-Page Support	Enables writing up to 64 bytes per I²C transaction without inter-byte delays - reduces bus occupancy time by >90% vs. byte-write for bulk calibration table updates.
Schmitt Trigger + Noise Filtering on SDA/SCL	Rejects transients ≤100 ns (tI) and suppresses EMI-induced glitches - maintains I²C communication integrity in noisy engine bay environments.
Self-Timed Write Cycle ≤5 ms	Internal write completion is automatic and deterministic - allows host MCU to poll ACK or use fixed timeout instead of complex status polling logic.
Green RoHS/Halide-Free Packaging	Lead-free SOIC with matte tin finish and halogen-free molding compound - satisfies automotive OEM environmental compliance requirements (e.g., BMW GS95024-3, VW TL813).
100-Year Data Retention at 55°C	Guaranteed nonvolatile storage lifetime exceeds typical vehicle service life - supports regulatory data logging mandates (e.g., OBD-II freeze frame, emission diagnostics).

Applications

Engine Control Unit (ECU)	Advanced Driver Assistance Systems (ADAS)
Use Scenario: Storing real-time learned fuel trim values, knock sensor adaptation maps, and misfire history across ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile parameter storage with guaranteed write integrity during cranking voltage dips and hot restarts. Use Value: Enables closed-loop engine optimization without requiring external backup power or supercapacitors - reduces BOM cost and board space.	Use Scenario: Retaining camera calibration offsets, radar object tracking history, and lane-departure warning thresholds between vehicle power cycles. IC Role / Device Role / Timing Role: Safety-critical configuration storage with hardware write-protection enabled during active driving phases. Use Value: Prevents accidental overwrites during CAN/FlexRay message bursts - ensures consistent sensor fusion behavior across all drive modes.
Body Control Module (BCM)	Electric Power Steering (EPS)
Use Scenario: Saving user preferences (mirror position, seat settings, lighting profiles) and door lock event logs for theft-deterrence reporting. IC Role / Device Role / Timing Role: Low-power, high-endurance data logger interfacing directly with 3.3V microcontroller I²C port. Use Value: Achieves <1 µA average standby current in sleep mode while supporting >10,000 configuration writes over 15-year vehicle life.	Use Scenario: Archiving torque sensor zero-point drift compensation, motor phase resistance calibration, and fault code history for ISO 26262 ASIL-B diagnostics. IC Role / Device Role / Timing Role: AEC-Q100 Grade 1 EEPROM integrated into ASIL-B safety island with WP pin tied to MCU-controlled GPIO. Use Value: Meets ASIL-B requirement for safe state preservation during voltage brownouts - no data corruption during EPS assist interruption.

Engine Control Unit (ECU)

Advanced Driver Assistance Systems (ADAS)

Use Scenario: Storing real-time learned fuel trim values, knock sensor adaptation maps, and misfire history across ignition cycles.

IC Role / Device Role / Timing Role: Nonvolatile parameter storage with guaranteed write integrity during cranking voltage dips and hot restarts.

Use Value: Enables closed-loop engine optimization without requiring external backup power or supercapacitors - reduces BOM cost and board space.

Use Scenario: Retaining camera calibration offsets, radar object tracking history, and lane-departure warning thresholds between vehicle power cycles.

IC Role / Device Role / Timing Role: Safety-critical configuration storage with hardware write-protection enabled during active driving phases.

Use Value: Prevents accidental overwrites during CAN/FlexRay message bursts - ensures consistent sensor fusion behavior across all drive modes.

Body Control Module (BCM)

Electric Power Steering (EPS)

Use Scenario: Saving user preferences (mirror position, seat settings, lighting profiles) and door lock event logs for theft-deterrence reporting.

IC Role / Device Role / Timing Role: Low-power, high-endurance data logger interfacing directly with 3.3V microcontroller I²C port.

Use Value: Achieves <1 µA average standby current in sleep mode while supporting >10,000 configuration writes over 15-year vehicle life.

Use Scenario: Archiving torque sensor zero-point drift compensation, motor phase resistance calibration, and fault code history for ISO 26262 ASIL-B diagnostics.

IC Role / Device Role / Timing Role: AEC-Q100 Grade 1 EEPROM integrated into ASIL-B safety island with WP pin tied to MCU-controlled GPIO.

Use Value: Meets ASIL-B requirement for safe state preservation during voltage brownouts - no data corruption during EPS assist interruption.

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STMicroelectronics M24C256-RMN6TP	Same 256-Kbit I²C EEPROM, AEC-Q100 Grade 1, but rated for 1.7–5.5V supply - wider low-voltage margin than AT24C256C-MAPD-T's 2.5–5.5V range.	Preferred where 1.8V microcontrollers or battery-backed operation below 2.5V is required; otherwise identical functional scope.	Select when system VCC may dip below 2.5V during cold-crank or energy harvesting scenarios.
ON Semiconductor CAT24C256HU4IGT3	256-Kbit I²C EEPROM with AEC-Q100 Grade 1, same 2.5–5.5V range, but offers 1 MHz Fast Mode Plus support - higher speed than AT24C256C-MAPD-T's 400 kHz limit.	Used where faster parameter loading is needed (e.g., OTA update staging), but requires MCU I²C peripheral capable of Fast Mode Plus timing.	Select only if host MCU supports Fast Mode Plus and bus timing budget allows tighter tLOW/tHIGH constraints.

Compared with M24C256-RMN6TP and CAT24C256HU4IGT3, the AT24C256C-MAPD-T delivers optimal balance of proven Grade 1 reliability, strict 400 kHz timing margin for legacy MCU compatibility, and SOIC package availability - making it the preferred choice for cost-sensitive, volume automotive programs with established design-in history.

Availability

AT24C256C-MAPD-T is available at Aetrix Electronics and suitable for engine control units, ADAS sensor modules, and body electronics requiring stable component supply across extended automotive lifecycles.

Supply support for AT24C256C-MAPD-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 is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with broad automotive qualification capabilities and global manufacturing traceability.

The AT24C256C belongs to Microchip's automotive-qualified serial EEPROM product line, designed specifically for robust, low-power nonvolatile storage in safety-critical vehicle subsystems operating under harsh thermal and electrical conditions.

FAQ

What is the maximum I²C clock frequency supported by the AT24C256C-MAPD-T?

The AT24C256C-MAPD-T supports I²C Fast Mode up to 400 kHz, with AC timing parameters fully characterized for tLOW ≥1200 ns and tHIGH ≥600 ns at VCC = 5.0V. It does not support Fast Mode Plus (1 MHz). This 400 kHz limit ensures reliable operation with widely deployed automotive microcontrollers lacking enhanced timing margins.

Does the AT24C256C-MAPD-T require external pull-up resistors on SDA and SCL lines?

Yes, the AT24C256C-MAPD-T requires external pull-up resistors on both SDA and SCL lines because its SDA pin is open-drain and SCL is input-only. Microchip specifies maximum pull-up resistance of 10 kΩ, with 1.3 kΩ recommended for 400 kHz operation to meet tR/tF rise/fall time requirements per I²C specification.

How is hardware write protection implemented on the AT24C256C-MAPD-T?

Hardware write protection on the AT24C256C-MAPD-T is controlled by the WP pin: when WP is driven high (≥0.7×VCC), all write operations to the entire memory array are inhibited; when WP is low (≤0.3×VCC) or floating (internally pulled down), normal write access is enabled. This provides deterministic, glitch-immune protection independent of firmware state.

What package type is used for the AT24C256C-MAPD-T?

The AT24C256C-MAPD-T uses an 8-lead SOIC package (3.9 mm × 4.9 mm, 1.27 mm pitch), designated by the "-MAPD-T" suffix. This package is pin-compatible with standard JEDEC MS-012AC SOIC footprints and supports automated optical inspection and reflow soldering per J-STD-020.

Is the AT24C256C-MAPD-T qualified to AEC-Q100, and which grade applies?

Yes, the AT24C256C-MAPD-T is AEC-Q100 qualified to Grade 1, meaning it is tested and certified for operation from –40°C to +125°C ambient temperature with full electrical characterization across that range - meeting requirements for powertrain, chassis, and safety-critical automotive applications.

AT24C256C-MAPD-T Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 8-UFDFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Active

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:: 400 kHz

Write Cycle Time - Word, Page:: 5ms

Access Time:: 900 ns

Voltage - Supply:: 2.5V ~ 5.5V

Operating Temperature:: -40°C ~ 125°C (TA)

Grade:: Automotive

Qualification:: AEC-Q100

Mounting Type:: Surface Mount

Supplier Device Package:: 8-UDFN (2x3)

AT24C256C-MAPD-T FAQ

1.How can I place an order for AT24C256C-MAPD-T through Aetrix?

Please submit a Request for Quotation (RFQ) for AT24C256C-MAPD-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 AT24C256C-MAPD-T reliable?

The price and inventory of AT24C256C-MAPD-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT24C256C-MAPD-T is usually 5 days.

3.What payment methods are accepted for AT24C256C-MAPD-T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT24C256C-MAPD-T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AT24C256C-MAPD-T?

AT24C256C-MAPD-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AT24C256C-MAPD-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 AT24C256C-MAPD-T?

For technical support, including AT24C256C-MAPD-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT24C256C-MAPD-T requirements.

6.How does Aetrix verify that AT24C256C-MAPD-T is sourced from the original manufacturer or authorized distributors?

All AT24C256C-MAPD-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 AT24C256C-MAPD-T meets industry standards.

7.What is the process for return or replacement of AT24C256C-MAPD-T?

All AT24C256C-MAPD-T units undergo pre-shipment inspection (PSI). If there is an issue with AT24C256C-MAPD-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 AT24C256C-MAPD-T part is unused and in its original packaging.

Return procedure for AT24C256C-MAPD-T:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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