© 2008 Microchip Technology Inc. DS22102A-page 5
24AA024H/24LC024H
2.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1: PIN FUNCTION TABLE
2.1 SDA Serial Data
This 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 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.
2.2 SCL Serial Clock
The SCL input is used to synchronize the data transfer
to and from the device.
2.3 A0, A1, A2
The A0, A1 and A2 inputs are used by the 24AA024H/
24LC024H 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
compare is true.
Up to eight 24AA024H/24LC024H 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.
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.
2.4 WP
WP is the hardware write-protect pin. It must be tied to
V
CC or VSS. If tied to VCC, the hardware write protection
is enabled and will protect half of the array (80h-FFh).
If the WP pin is tied to VSS the hardware write
protection is disabled.
2.5 Noise Protection
The 24AA024H/24LC024H employs a VCC threshold
detector circuit that disables the internal erase/write
logic if the VCC is below 1.5 volts at nominal conditions.
The SCL and SDA inputs have Schmitt Trigger and
filter circuits that suppress noise spikes to assure
proper device operation even on a noisy bus.
Name
8-pin
PDIP
8-pin
SOIC
8-pin
TSSOP
8-pin
MSOP
8-pin
TDFN
Function
A0 1 1 1 1 1 User Configurable Chip Select
A1 2 2 2 2 2 User Configurable Chip Select
A2 3 3 3 3 3 User Configurable Chip Select
V
SS 44444Ground
SDA 5 5 5 5 5 Serial Data
SCL 6 6 6 6 6 Serial Clock
WP 7 7 7 7 7 Write-Protect Input
V
CC 8 8 8 8 8 +1.7V to 5.5V (24AA024H)
+2.5V to 5.5V (24LC024H)
