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AT24C02

2-Wire I2C serial EEPROM with 2 Kbit (256 x 8) memory for nonvolatile data storage.

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Manufacturer Part：

AT24C02

Package：

8-SOIC / 8-PDIP / 8-TSSOP / 5-SOT23

Description

The AT24C02 by Microchip (formerly Atmel) is a 2 Kbit (256 x 8) I2C serial EEPROM providing nonvolatile data storage with 1 million write cycle endurance and 100-year data retention. It operates from 1.8V to 5.5V with I2C clock rates up to 400 kHz (1 MHz on CS-series FM+ mode). The device supports 8-byte page write with 5 ms self-timed write cycle, up to 8 devices on the same bus via A0-A2 address pins, and hardware write protection via the WP pin. Standby current is typically 6 uA.

Available in 8-SOIC, 8-PDIP, 8-TSSOP, 5-SOT23, 8-MAP, and 8-dBGA2 packages with industrial (-40 to +85C) and automotive-grade (-40 to +125C) temperature options. The AT24CS02 variant includes a factory-programmed 128-bit unique serial number. RoHS compliant and halogen-free. Target applications include configuration storage, data logging, device identification, and consumer/automotive electronics.

Product Introduction:AT24C02 Product Introduction

The AT24C02 is a 2-Wire Serial EEPROM manufactured by Microchip Technology (formerly Atmel), providing 2048 bits (256 x 8) of electrically erasable and programmable read-only memory. The device is accessed via an I2C-compatible serial interface supporting 100 kHz (1.8V) and 400 kHz (2.7V/5V) clock rates, with newer CS-series variants supporting 1 MHz (FM+) mode above 2.5V.

The AT24C02 operates from a supply voltage of 1.8V to 5.5V, with 8-byte page write mode and self-timed write cycle of 5 ms maximum. It supports up to 8 devices on the same I2C bus via three address input pins (A0-A2). The WP (Write Protect) pin provides hardware data protection for the entire memory array. Key reliability specifications include 1 million write cycle endurance and 100-year data retention.

The device is available in multiple package options including 8-lead PDIP, 8-lead JEDEC SOIC, 8-lead TSSOP, 5-lead SOT23, 8-lead MAP, and 8-ball dBGA2. The operating temperature range is -40 to +85C (industrial), with automotive-grade devices supporting -40 to +125C. The AT24C02 is RoHS compliant and halogen-free. The AT24CS02 variant includes a factory-programmed 128-bit unique serial number.

Working Principle:AT24C02 Working Principle

The AT24C02 operates as an I2C slave EEPROM device:

1. I2C Interface: The device communicates via a 2-wire serial bus (SDA for data, SCL for clock). Both lines are open-drain and require external pull-up resistors. The device supports Standard Mode (100 kHz), Fast Mode (400 kHz), and FM+ Mode (1 MHz on CS-series).

2. Device Addressing: The 7-bit slave address consists of a 4-bit device type identifier (1010), followed by three address bits (A2, A1, A0) set by the hardware pins, and a R/W bit. This allows up to 8 AT24C02 devices on the same bus.

3. Memory Organization: The 2 Kbit memory is organized as 256 words of 8 bits each. Memory is accessed via an 8-bit address byte sent after the slave address during a write or read operation.

4. Write Operation: Supports byte write and page write (8-byte page). During a page write, up to 8 bytes can be written in a single cycle. The internal address counter increments within the page boundary (wraps around within the same page). The self-timed write cycle takes up to 5 ms, during which the device does not acknowledge I2C commands (ACK polling can be used to detect completion).

5. Read Operation: Supports random read (address specified), sequential read (address auto-increments), and current address read (reads from the address of the last access + 1).

6. Write Protection: When the WP pin is connected to VCC, all write operations to the entire memory array are inhibited. Connecting WP to GND allows normal read/write operations.

7. Power Management: The device enters standby mode when no I2C activity is present, drawing typically 6 uA or less.

Pin Description:AT24C02 Pin Definition and Functions

Pin	Name	Type	Description
1	A0	I	Address input bit 0 for device selection on I2C bus
2	A1	I	Address input bit 1 for device selection on I2C bus
3	A2	I	Address input bit 2 for device selection on I2C bus
4	GND	G	Ground reference
5	SDA	I/O	Serial data input/output (open-drain, requires external pull-up)
6	SCL	I	Serial clock input
7	WP	I	Write protect; HIGH = protect entire array, LOW = normal operation
8	VCC	P	Power supply (1.8V to 5.5V)

Application Scenarios:In which products and applications isAT24C02 used

Application	Description
Configuration Storage	Stores calibration data, user settings, and configuration parameters that must survive power cycles in embedded systems
Data Logging	Records small datasets such as event logs, error counters, and diagnostic information in industrial and consumer devices
Device Identification	AT24CS02 variant with 128-bit factory-programmed serial number for unique device identification and anti-counterfeiting
Consumer Electronics	Channel presets, volume settings, and user preferences in TVs, audio systems, and home appliances
Automotive Systems	AEC-Q100 qualified variants for storing ECU parameters, sensor offsets, and diagnostic data in automotive electronics

Alternative Models:What chips are recommended as replacements for AT24C02

Model	Manufacturer	Compatibility	Key Difference
AT24C04	Microchip	Series Sibling	4 Kbit (512 x 8), same pinout, same I2C protocol
AT24C16A	Microchip	Series Sibling	16 Kbit (2048 x 8), same pinout, 16-byte page write
24LC02B	Microchip	Series Equivalent	2 Kbit I2C EEPROM, LC series with different addressing scheme
M24C02-W	STMicroelectronics	Competitive Alternative	2 Kbit I2C EEPROM, similar specs, different manufacturer
DS2431	Maxim/Analog	Competitive Alternative	1-Wire (not I2C) 4 Kbit EEPROM, different interface protocol