2.1 Device Address Inputs (A1, A2)

The A1 and A2 pins are device address inputs that are hardwired (directly to GND or to V_CC) for compatibility with other Two-Wire Serial EEPROM devices. When the pins are hardwired on the AT24C04C, as many as four devices may be addressed on a single bus system. When the A2 pin is hardwired on the AT24C08C, as many as two devices may be addressed on a single bus system. A device is selected when a corresponding hardware and software match is true. If the pins are left floating, the A1 and A2 pins will be internally pulled down to GND. However, due to capacitive coupling that may appear in customer applications, connecting the address pins to a known state is recommended. When using a pull-up resistor, using 10 kΩ or less is recommended.