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Non-volatile memory devices allow data to remain stored even when power is removed. One widely used device for this purpose is the AT24C02 EEPROM. This article will discuss the AT24C02 EEPROM basics, pinout details, variants, block diagram, specifications, features, working principle with Arduino, usage scenarios, etc.
The AT24C02 EEPROM is a 2-Kbit two-wire serial EEPROM designed for reliable non-volatile data storage. It stores information even when the power is turned off, making it useful for keeping configuration or system data. The device contains 2048 bits of memory, organized as 256 words of 8 bits each, allowing small amounts of data to be written, erased, and read repeatedly.
The AT24C02 communicates through a two-wire serial interface based on the I²C communication protocol, using only SDA (Serial Data) and SCL (Serial Clock) lines. This simple interface helps reduce wiring and allows easy communication with many digital systems. The device also supports low-voltage operation and efficient power usage, making it suitable for compact electronic designs.
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| Pin No. | Pin Name | Type | Description |
| 1 | A0 | Input | Address input pin used to set the device address. It allows multiple EEPROM devices to share the same I²C bus. |
| 2 | A1 | Input | Address input pin that helps define the device address for communication. |
| 3 | A2 | Input | Address input pin used together with A0 and A1 to select the EEPROM device on the bus. |
| 4 | GND | Power | Ground connection for the device. |
| 5 | SDA | Bidirectional | Serial Data line used to transfer data between the EEPROM and the controller through the I²C interface. |
| 6 | SCL | Input | Serial Clock line that synchronizes data transfer in the I²C communication protocol. |
| 7 | WP | Input | Write Protect pin. When connected to VCC, it prevents writing to the memory to protect stored data. |
| 8 | VCC | Power | Power supply pin for the EEPROM device. |
| Equivalent Model | Manufacturer | Memory Size | Interface | Package Options |
| M24C02 | STMicroelectronics | 2 Kbit (256 × 8) | I²C | DIP-8, SOIC-8, TSSOP |
| CAT24C02 | onsemi | 2 Kbit (256 × 8) | I²C | DIP-8, SOIC-8 |
| 24LC02 | Microchip Technology | 2 Kbit (256 × 8) | I²C | DIP-8, SOIC-8, TSSOP |
| IS24C02 | Integrated Silicon Solution Inc. | 2 Kbit (256 × 8) | I²C | DIP-8, SOIC-8 |
| BR24G02 | ROHM Semiconductor | 2 Kbit (256 × 8) | I²C | SOP-8, TSSOP |
| FT24C02A | Fremont Micro Devices | 2 Kbit (256 × 8) | I²C | SOP-8 |
| Ordering Code | Package Code | Package Type | Supply Voltage | Memory Size | Temperature Range |
| AT24C02-10PU-2.7 | 8P3 | 8-lead Plastic Dual Inline Package (PDIP), 0.300″ | 2.7V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02-10PU-1.8 | 8P3 | 8-lead Plastic Dual Inline Package (PDIP), 0.300″ | 1.8V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02N-10SU-2.7 | 8S1 | 8-lead Plastic Gull Wing Small Outline (JEDEC SOIC), 0.150″ | 2.7V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02N-10SU-1.8 | 8S1 | 8-lead Plastic Gull Wing Small Outline (JEDEC SOIC), 0.150″ | 1.8V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02-10TU-2.7 | 8A2 | 8-lead Thin Shrink Small Outline Package (TSSOP), 4.4 mm body | 2.7V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02-10TU-1.8 | 8A2 | 8-lead Thin Shrink Small Outline Package (TSSOP), 4.4 mm body | 1.8V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02Y1-10YU-1.8 | 8Y1 | 8-lead Miniature Array Package (MAP), 4.90 mm × 3.00 mm body | 1.8V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02-10TSU-1.8 | 5TS1 | 5-lead Thin Shrink Small Outline Package (SOT23), 2.90 mm × 1.60 mm | 1.8V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02U3-10UU-1.8 | 8U3-1 | 8-ball Die Ball Grid Array (dBGA2) | 1.8V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
| AT24C02-W2.7-11 | Die | Bare Die | 2.7V – 5.5V | 2 Kbit (256 × 8) | -40°C to 85°C |
The functional block diagram of the AT24C02 shows how the device manages communication and memory operations. The SCL (clock) and SDA (data) lines enter the Start/Stop logic, which detects the beginning and end of I²C communication. After this, the signals move to the Serial Control Logic, which controls data transfer, read/write operations, and overall communication timing inside the chip.
The Device Address Comparator checks the address sent by the controller against the hardware address pins A0, A1, and A2. If the address matches, the EEPROM responds and allows access to the memory. The Data Word Address Counter then selects the correct memory location where data will be written or read.
Inside the memory section, the X and Y decoders choose the exact cell within the EEPROM array. During write operations, the High-Voltage Pump and Timing circuit generates the required voltage to store data in the EEPROM cells. The Data Recovery and Serial MUX blocks manage data retrieval and send the output through the DOUT/ACK logic back to the SDA line.
| Parameter | Value |
| Memory Type | Serial EEPROM |
| Memory Capacity | 2 Kbit (256 × 8 bits) |
| Interface | Two-Wire Serial Interface (I²C) |
| Operating Voltage | 1.8 V – 5.5 V (depending on variant) |
| Maximum Operating Voltage | 6.25 V |
| Operating Temperature | −40°C to +85°C |
| Storage Temperature | −65°C to +150°C |
| Voltage on Any Pin (Relative to GND) | −1.0 V to +7.0 V |
| Write Cycle Time | Typically 5 ms |
| Page Write Size | 8 bytes |
| Clock Frequency | Up to 1 MHz (depending on version) |
| Endurance | Up to 1,000,000 write cycles |
| Data Retention | Up to 100 years |
| Address Inputs | 3 (A0, A1, A2) |
| DC Output Current | 5 mA (max) |
| Write Protection | Hardware Write Protect (WP) pin |
| Package Options | PDIP-8, SOIC-8, TSSOP-8, SOT-23-5, MAP, dBGA |
The AT24C02 supports both standard and low-voltage operation. Depending on the version, the device operates from 2.7 V to 5.5 V or 1.8 V to 5.5 V, allowing it to work with different digital systems and low-power electronics.
The AT24C02 provides 2 Kbits of non-volatile memory, organized as 256 × 8 bits. Internally, the memory is divided into 32 pages with 8 bytes per page, enabling efficient storage and page write operations.
The device communicates through a two-wire I²C interface using SDA (Serial Data) and SCL (Serial Clock) lines. This simple communication method allows easy integration with microcontrollers.
The AT24C02 includes Schmitt trigger inputs and filtered input circuits. These features help suppress noise and improve signal stability during communication.
The EEPROM supports bidirectional serial communication, allowing both reading and writing of data through the same SDA line controlled by the clock signal on SCL.
A dedicated Write Protect (WP) pin is available to protect stored data. When the WP pin is enabled, write operations are disabled to prevent accidental modification of memory contents.
The AT24C02 supports 8-byte page write operations, allowing multiple bytes to be written to the EEPROM in a single write cycle for faster programming.
The device includes an internal self-timed write cycle, typically completed within 5 ms, which automatically handles the EEPROM programming process.
The AT24C02 offers high endurance and long data retention, supporting up to 1 million write cycles and maintaining stored data for up to 100 years under normal operating conditions.
The EEPROM is available in several package types, including 8-lead PDIP, SOIC, TSSOP, Ultra Thin Mini-MAP, 5-lead SOT-23, and 8-ball dBGA, providing flexibility for different PCB layouts and compact electronic designs.
The device supports 100 kHz operation for 1.8 V versions and up to 400 kHz operation for 2.7 V and 5 V versions, ensuring compatibility with standard I²C bus speeds.
Some AT24C02 versions are designed to meet automotive-grade reliability standards, allowing use in environments requiring higher reliability and stability.
How the AT24C02 EEPROM is connected to an Arduino Uno using the I²C communication protocol? The EEPROM receives power from the 5 V supply, with VCC connected to 5 V and GND connected to ground. The three address pins A0, A1, and A2 are tied to ground, which sets the device I²C address. This configuration allows the Arduino to communicate with the EEPROM using a fixed device address on the bus.
The SDA (Serial Data) and SCL (Serial Clock) pins of the EEPROM are connected to the Arduino’s A4 (SDA) and A5 (SCL) pins. Two 4.7 kΩ resistors are connected from SDA and SCL to the 5 V supply. These resistors act as pull-up resistors, which are required for proper I²C communication because the bus uses open-drain signaling.
During operation, the Arduino sends commands and data through the SDA line while the SCL line provides the timing signal. The AT24C02 receives the device address and memory address from the Arduino, then stores or retrieves data from its internal EEPROM array. Data written to the chip remains stored even when power is removed.
• Storing configuration settings in microcontroller-based systems
• Saving calibration data for sensors and measurement devices
• Keeping system parameters in embedded electronics
• Storing small amounts of non-volatile data in control circuits
• Retaining device identification or serial number information
• Storing firmware parameters or system flags
• Saving user preferences in electronic devices
• Storing lookup tables or small data tables for embedded programs
• Backup storage for small critical data values
• Non-volatile memory support for I²C-based digital systems
| Parameter | AT24C01 | AT24C02 | AT24C04 | AT24C08 | AT24C16 |
| Memory Capacity | 1 Kbit | 2 Kbit | 4 Kbit | 8 Kbit | 16 Kbit |
| Memory Organization | 128 × 8 | 256 × 8 | 512 × 8 | 1024 × 8 | 2048 × 8 |
| Page Write Size | 8 Bytes | 8 Bytes | 16 Bytes | 16 Bytes | 16 Bytes |
| Word Address Size | 7-bit | 8-bit | 8-bit | 8-bit | 8-bit |
| Interface | I²C | I²C | I²C | I²C | I²C |
| Operating Voltage | 1.8–5.5 V | 1.8–5.5 V | 1.8–5.5 V | 1.8–5.5 V | 1.8–5.5 V |
| Typical Write Time | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms |
| Endurance | 1M cycles | 1M cycles | 1M cycles | 1M cycles | 1M cycles |
| Data Retention | 100 years | 100 years | 100 years | 100 years | 100 years |
| Common Packages | PDIP, SOIC | PDIP, SOIC, TSSOP | PDIP, SOIC | PDIP, SOIC | PDIP, SOIC |
Atmel Corporation had strong semiconductor manufacturing capabilities in producing non-volatile memory devices such as the AT24C02 EEPROM. The company specialized in designing and fabricating reliable serial EEPROM chips optimized for low-power operation, high endurance write cycles, and long data retention. Atmel used advanced semiconductor fabrication processes and operated multiple global facilities to support large-scale production of memory devices and embedded components. Its manufacturing capabilities also included flexible packaging technologies, allowing devices like the AT24C02 to be offered in formats such as PDIP, SOIC, TSSOP, SOT-23, and dBGA. These capabilities enabled Atmel to supply high-quality EEPROM solutions for various embedded and electronic systems.
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