X24256
Characteristics subject to change without notice.
2 of 18
PIN DESCRIPTIONS
Serial Clock (SCL)
The SCL input is used to clock all data into and out of
the device.
Serial Data (SDA)
SDA is a bidirectional pin used to transfer data into
and out of the device. It is an open drain output and
may be wire-ORed with any number of open drain or
open collector outputs.
An open drain output requires the use of a pull-up
resistor. For selecting typical values, refer to the Pull-
up resistor selection graph at the end of this data
sheet.
Device Select (S
The device select inputs (S
the slave address. This allows up to four devices to
share a common bus. These inputs can be static or
actively driven. If used statically they must be tied to
V
SS
or V
CC
as appropriate. If actively driven, they
must be driven with CMOS levels (driven to V
V
SS
) and they must be constant between each start
and stop issued on the SDA bus. These pins have an
active pull down internally and will be sensed as low if
the pin is left unconnected.
0
, S
1
)
0
, S
1
) are used to set bits in
CC
or
Write Protect (WP)
WP must be constant between each start and stop
issued on the SDA bus and is always active (not
gated). The WP pin has an active pull down to disable
the write protection when the input is left floating. The
Write Protect input controls the Hardware Write Pro-
tect feature. When held LOW, Protection is disabled
and the device operates normally. When this input is
held HIGH, the device is protected, preventing
changes to any and all locations in the EEPROM array.
PIN NAMES
PIN CONFIGURATION
Symbol
S
0
, S
SDA
SCL
WP
V
SS
V
CC
NC
Description
1
Device Select Inputs
Serial Data
Serial Clock
Write Protect
Ground
Supply Voltage
No Connect
8 Lead PDIP/SOIC
VCC
WP
SCL
SDA
S0
S1
NC
1
2
3
4
6
5
7
8
X24256
VSS
14 Lead TSSOP
VCC
WP
NC
NC
SCL
SDA
S0
S1
NC
NC
NC
NC
1
2
3
4
5
7
6
X24256
VSS
NC
8
9
10
11
12
14
13
8-Lead XBGA: Top View
S
1
SDA
NC
SCL
VCC
VSS
S
0
WP
8
7
6
5
1
2
3
4
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