Datasheet

24AA64/24LC64
DS21189H-page 12  2003 Microchip Technology Inc.
7.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 7-1.
TABLE 7-1: PIN FUNCTION TABLE
7.1 A0, A1, A2 Chip Address Inputs
The A0, A1 and A2 inputs are used by the 24XX64 for
multiple device operation. The levels on these inputs
are compared with the corresponding bits in the slave
address. The chip is selected if the compare is true.
Up to eight devices may be connected to the same bus
by using different Chip Select bit combinations. These
inputs must be connected to either V
CC or VSS.
7.2 Serial Data (SDA)
SDA is a bidirectional pin used to transfer addresses
and data into and out of the device. Since it is an open-
drain terminal, the SDA bus requires a pull-up resistor
to V
CC (typical 10 kΩ for 100 kHz, 2 kΩ for 400 kHz).
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.
7.3 Serial Clock (SCL)
The SCL input is used to synchronize the data transfer
from and to the device.
7.4 Write-Protect (WP)
WP can be connected to either VSS, VCC or left floating.
An internal pull-down resistor on this pin will keep the
device in the unprotected state if left floating. If tied to
V
SS, or left floating, normal memory operation is
enabled (read/write the entire memory 0000-1FFF).
If tied to V
CC, write operations are inhibited. Read
operations are not affected.
Name PDIP SOIC TSSOP MSOP
ROTATED
TSSOP
Description
A0 1 1 1 1 3 Chip Address Input
A1 2 2 2 2 4 Chip Address Input
A2 3 3 3 3 5 Chip Address Input
V
SS 4444 6Ground
SDA 5 5 5 5 7 Serial Address/Data I/O
SCL 6 6 6 6 8 Serial Clock
WP 7 7 7 7 1 Write-Protect Input
V
CC 8 8 8 8 2 +1.8V to 5.5V Power Supply