24AA1025_08 Datasheet, PDF (5/24 Pages) Microchip Technology – 1024K I2C™ CMOS Serial EEPROM

24AA1025/24LC1025/24FC1025
2.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1: PIN FUNCTION TABLE
Name PDIP SOIJ
Function
A0 1
A1 2
A2 3
VSS 4
SDA 5
SCL 6
WP 7
VCC 8
1 User Configurable Chip Select
2 User Configurable Chip Select
3 Non-Configurable Chip Select.
This pin must be hard-wired to
logical 1 state (VCC). Device
will not operate with this pin
left floating or held to logical 0
(VSS).
4 Ground
5 Serial Data
6 Serial Clock
7 Write-Protect Input
8 +1.7 to 5.5V (24AA1025)
+2.5 to 5.5V (24LC1025)
+1.8 to 5.5V (24FC1025)
2.1 A0, A1 Chip Address Inputs
The A0 and A1 inputs are used by the 24XX1025 for
multiple device operations. The levels on these inputs
are compared with the corresponding bits in the slave
address. The chip is selected if the comparison is true.
Up to four devices may be connected to the same bus
by using different Chip Select bit combinations. In most
applications, the chip address inputs A0 and A1 are
hard-wired to logic ‘0’ or logic ‘1’. For applications in
which these pins are controlled by a microcontroller or
other programmable device, the chip address pins
must be driven to logic ‘0’ or logic ‘1’ before normal
device operation can proceed.
2.2 A2 Chip Address Input
The A2 input is non-configurable Chip Select. This pin
must be tied to VCC in order for this device to operate.
2.3 Serial Data (SDA)
This is a bidirectional pin used to transfer addresses
and data into and data out of the device. It is an open-
drain terminal, therefore, the SDA bus requires a pull-
up resistor to VCC (typical 10 kΩ for 100 kHz, 2 kΩ for
400 kHz and 1 MHz).
For normal data transfer SDA is allowed to change only
during SCL low. Changes during SCL high are
reserved for indicating the Start and Stop conditions.
2.4 Serial Clock (SCL)
This input is used to synchronize the data transfer from
and to the device.
2.5 Write-Protect (WP)
This pin must be connected to either VSS or VCC. If tied
to VSS, write operations are enabled. If tied to VCC,
write operations are inhibited, but read operations are
not affected.
© 2008 Microchip Technology Inc.
DS21941F-page 5