Microchip AT24C02D-XHM-T 2-Wire Serial EEPROM Memory Chip Datasheet and Application Circuit Design Guide

Introduction to the AT24C02D-XHM-T

The AT24C02D-XHM-T is a 2-wire serial EEPROM memory chip manufactured by Microchip Technology. This device provides 2048 bits of organized memory, configured as 256 x 8 bits. It is designed for a wide range of applications requiring non-volatile data storage, such as system configuration parameters, user preferences, and data logging in consumer electronics, industrial systems, and IoT devices. Its 2-wire serial interface (I²C-compatible) allows for efficient communication with microcontrollers using only two bidirectional lines, making it ideal for space-constrained designs.

Key Features and Electrical Characteristics

The AT24C02D-XHM-T operates from 1.7V to 5.5V, supporting a broad spectrum of voltage levels commonly found in modern electronic systems. This wide voltage range ensures compatibility with various microcontrollers and processors. The device features a 16-byte page write buffer, enabling faster data writing compared to single-byte operations. It also supports partial page writes, allowing for efficient memory management.

With a maximum operating frequency of 1MHz (at 5V), the EEPROM ensures high-speed data transfer. It offers high reliability with an endurance of 1 million write cycles and a data retention period of 100 years. These characteristics make it suitable for applications requiring frequent updates and long-term data integrity.

The AT24C02D-XHM-T is available in a compact TSSOP-8 package, which is beneficial for PCB designs with limited space. It also includes hardware write-protection via the WC (Write Control) pin, preventing accidental data modification.

Application Circuit Design Guide

Designing with the AT24C02D-XHM-T is straightforward due to its simple interface. The primary connections involve the Serial Data (SDA) and Serial Clock (SCL) lines, which form the I²C bus. These lines must be pulled up to the supply voltage (VCC) using appropriate resistors (typically 4.7 kΩ to 10 kΩ). The pull-up resistors ensure the bus lines remain high when not actively driven by the master or slave device.

The device address pins (A0, A1, A2) allow for connecting up to eight identical devices on the same bus. These pins can be tied to GND or VCC to set the unique hardware address for each chip. The Write Control (WC) pin should be connected to GND for normal write operations or to VCC to enable write protection.

A typical application circuit includes:

- Power supply decoupling: A 0.1 µF ceramic capacitor placed close to the VCC and GND pins to filter noise.

- I²C pull-up resistors: Connected from SDA and SCL to VCC.

- Address configuration: Setting A0, A1, and A2 to logic low or high as needed.

- Write protection control: Connecting the WC pin based on the design requirements.

Software Implementation Considerations

When interfacing with a microcontroller, the I²C protocol must be implemented correctly. The master (microcontroller) initiates communication by sending a start condition followed by the device address (including the R/W bit). The AT24C02D-XHM-T supports random and sequential read modes, providing flexibility in data retrieval. For write operations, the page write function should be utilized to maximize efficiency.

It is crucial to observe the tWR (write cycle time) of 5 ms maximum after a write command. During this period, the device will not acknowledge further commands, a state known as internal write cycle polling. The master must wait until the write cycle completes before proceeding.

ICGOOODFIND

The Microchip AT24C02D-XHM-T is a highly reliable and versatile serial EEPROM, offering easy integration into modern electronic systems. Its low power consumption, wide voltage operation, and robust data retention make it an excellent choice for designers seeking efficient non-volatile memory solutions. The well-defined datasheet and straightforward application circuit ensure a smooth design process, reducing time to market for various products.

Keywords:

I²C Interface, Non-Volatile Memory, Page Write, Hardware Write Protection, Data Retention