AT24C02 EEPROM Explained: Features, Pinout, Interfacing & Use Cases for IoT Projects

What is AT24C02 EEPROM?

The AT24C02 is a 2-Kilobit (256 x 8) serial Electrically Erasable Programmable Read-Only Memory (EEPROM) developed by Microchip Technology. It uses the I2C (Inter-Integrated Circuit) protocol for communication, allowing easy interfacing with microcontrollers and digital devices. Designed for non-volatile memory storage, it retains data even after power is removed.

This makes it a go-to solution for storing configuration data, calibration settings, and temporary logs in embedded systems.

Key Features of AT24C02

• Memory Size: 2Kb (256 bytes total; organized as 32 pages of 8 bytes)

• Interface: I²C (2-wire)

• Operating Voltage: 1.7V to 5.5V (compatible with both 3.3V and 5V logic)

• Low Power Consumption: 1 µA standby current

• Write Time: Typical 5ms

• Write Protection: Hardware-based write protection via WP pin

• Data Retention: 100 years

• Endurance: 1,000,000 write/erase cycles

• Package Types: 8-lead SOIC, DIP, TSSOP, UDFN

AT24C02 Pinout Description

These address pins (A0–A2) allow users to configure the device's I2C address — enabling up to 8 devices on the same I2C bus.

How AT24C02 Works

AT24C02 operates on the master-slave communication model. When connected to a microcontroller, the EEPROM acts as a slave device. The microcontroller sends the memory address and either writes data to it or reads data from it over the I2C protocol. The EEPROM handles internal memory management automatically.

Each write operation is internally acknowledged by the EEPROM and can take up to 5ms to complete.

Package Types of AT24C02

1. AT24C02N – DIP-8 package (through-hole, breadboard-friendly)

2. AT24C02C – SOIC-8 package (surface mount)

3. AT24C02B – Automotive grade

4. AT24C02D – Industrial-grade temperature and voltage support

5. AT24C02-MAHM – 8-lead UDFN for ultra-compact devices

Each variant is functionally the same but offered in different form factors for use in industrial, commercial, or space-limited applications.

Interfacing AT24C02 with Microcontrollers

To interface AT24C02 with a microcontroller:

• Connect SDA and SCL lines to the respective I2C pins on the microcontroller
• Pull-up resistors (typically 4.7kΩ to 10kΩ) are required on SDA and SCL lines
• Connect VCC and GND to power and ground
• If not using write protection, tie the WP pin to GND

Important Note: Always monitor I²C address collisions when using multiple I2C devices on the same bus.

Advantages of Using AT24C02

• Reliable non-volatile memory
• Simple I2C interface for easy programming
• Low power and small form factor
• Cost-effective for small data storage needs
• Supports multiple devices on the same bus via address pins

Example: Writing and Reading Data from AT24C02 (Pseudo Code)