24AA32AF Datasheet, PDF (5/30 Pages) Microchip Technology – 32K I2C™ Serial EEPROM with Quarter-Array Write-Protect

24AA32AF/24LC32AF
2.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1: PIN FUNCTION TABLE
Name
PDIP
SOIC TSSOP
A0
1
1
1
A1
2
2
2
A2
3
3
3
VSS
4
4
4
SDA
5
5
5
SCL
6
6
6
WP
7
7
7
VCC
8
8
8
TDFN
1
2
3
4
5
6
7
8
MSOP
1
2
3
4
5
6
7
8
SOT-23
Description
— Chip Address Input
— Chip Address Input
— Chip Address Input
2 Ground
3 Serial Address/Data I/O
1 Serial Clock
5 Write-Protect Input
4 +1.7V to 5.5V Power Supply
2.1 A0, A1, A2 Chip Address Inputs
The A0, A1 and A2 inputs are used by the 24XX32AF
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 comparison 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 VCC or VSS.
In most applications, the chip address inputs A0, A1
and A2 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. Address
pins are not available in the SOT-23 package.
2.2 Serial Data (SDA)
SDA is a bidirectional pin used to transfer addresses
and data into and 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)
For normal data transfer, SDA is allowed to change
only during SCL low. Changes during SCL high are
reserved for indicating Start and Stop conditions.
2.3 Serial Clock (SCL)
The SCL input is used to synchronize the data transfer
to and from the device.
2.4 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 for the upper 1/4 of the
array (C00h-FFFh), but read operations are not
affected.
© 2009 Microchip Technology Inc.
DS22184A-page 5