Datasheet

24AA64/24LC64
DS21189F-page 12  2002 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, A2 inputs are used by the 24XX64 for mul-
tiple 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)
This is a bi-directional 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 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 condi-
tions.
7.3 Serial Clock (SCL)
This input is used to synchronize the data transfer from
and to the device.
7.4 Write Protect (WP)
This pin 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 4 4 4 4 6 Ground
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