AT24C04 4-Kbit Serial EEPROM

20 November 2019 - 0 Comments

AT24C04 Serial EEPROM IC

AT24C04 EEPROM Pinout

The AT24C04 provides 4096 bits of serial electrically erasable and programmable read-only memory (EEPROM) organized as 512 words of 8 bits each. AT24C04 is optimized for use in many industrial and commercial applications where low-power and low-voltage operations are essential.

Pin Description of AT24C04:

Pin Number	Pin Name	Description
1,2,3	A0,A1,A2	User configured Chip Select pins, useful during cascading
4	Vss (Ground)	Connected to the ground of the circuit
5	Serial Data (SDA)	Serial Data pin for I2C Communication
6	Serial Clock (SCL)	Serial Clock pin for I2C Communication
7	Write-Protect	If connected to Vss write is enabled, if connected to Vcc write is disabled.
8	Vcc	Connect to supply rail

Specifications of AT24C04

Maximum Clock Frequency:1 MHz
Supply Current - Max:1 mA
Supply Voltage - Min:1.7 V
Supply Voltage - Max:3.6 V
Operating Voltage: 1.7V to 3.6V
Internally Organized 512 x 8 (4K) memory
Communication: Serial, 2-Wire, I2C
Write cycle time: 5ms
16-byte Page (4K) Write Modes
Available in 8-lead PDIP, SOIC, Ultra-Thin Mini-MAP (MLP 2x3), 5-lead SOT23, 8-lead TSSOP and 8-ball dBGA2 Packages.

Note: Complete Technical Details can be found at the AT24C04 datasheet give at the end of this page.

Equivalent of AT24C04: 24LC512

Alternatives EEPROM’S: 24LC1026, 25LC050, 24C32

Where to use the AT24C04 EEPROM:

The AT24C04is a 512 Kilo Bit, 8-pin EEPROM IC. As we know EEPROM stands for Electrically Erasable Programmable Read-Only Memory, we can store information on this IC and it will remain there even when the power is turned off just like your pen drive. Then the information can be retrieved or over-written when required.

It has a wide operating voltage range from 1.7V to 3.6V, which makes it ideal to be used both for 3.3V systems. Each IC comes with a storage space of 512Kb and can be cascaded with 8 similar IC if expansion is required. The IC works with help of 2-wire protocol (IIC/I2C) and hence it is easy to interface with most of the MCU’s and consumes fewer pins.

So if you are looking for an EEPROM IC with storage of 512KB and works on Serial, 2-Wire, I2C then this IC might be the right choice for you.

How to use AT24C04 EEPROM IC:

The AT24C04 EEPROM IC communicates with the help of the I2C protocol. To interface it with an MCU just power the IC (with 3.3V) and connect the communication lines as shown below.

AT24C04 Interfacing Circuit Diagram

The Serial Clock SCK (pin 6) is connected to the Serial clock pin of the microcontroller and the Serial Data SDA (pin 5) is connected to the Serial Data pin of the microcontroller. Also like all I2C communication we have pulled the SCK and SDA line high using two pull-up resistors or while 4.7k. This will keep the bus at high state during the idle condition.

Other than that we have three chip select pins namely A0, A1, and A2. These three pins are useful only if more than one I2C device or EEPROM is connected to the same microcontroller, else three pins can be grounded directly. In the above diagram, we have connected the three pins to the GPIO pins so that we can cascade more than one EEPROM IC if required.

The Write Protect WP (pin 7) is provided for improving data security in the IC. The data can be written or erased on the EEPROM only if the WP pin is held low (logic 0). Else the data written on the EEPROM will remain as such. Normally this pin will be grounded (logic 0) when the protection is not needed. Data can be read from the EEPROM at all conditions irrespective of the status of the WP pin.

Once the communication is successful the MCU can be programmed to read/write data to the EEPROM by calling the right register values. First, the address of the location to which the data must be read/written should be specified followed by the data. Normally this is how data will be read/written byte by byte. The AT24C04 IC provides an option called page write which allows the user to write 128-bytes of data continuously without mention the address of each data. Read the datasheet at the end of the page to know more about how to communicate with the IC.