CAT24C21
1-kb Dual Mode Serial EEPROM for VESA鈩?"Plug-and-Play"
FEATURES
s
DDC1
TM
/DDC2
TM
interface compliant for
s
Low power CMOS technology
s
1,000,000 program/erase cycles
s
100 year data retention
H
GEN
FR
ALO
EE
LE
A
D
F
R
E
E
TM
monitor identification
s
400 kHz I C bus compatible*
s
2.5 to 5.5 volt operation
s
16-byte page write buffer
s
Hardware write protect
2
s
8-pin DIP, SOIC, TSSOP, MSOP or TDFN
packages
s
Industrial temperature range
DESCRIPTION
The CAT24C21 is a 1-kb Serial CMOS EEPROM
internally organized as 128 words of 8 bits each. The
device complies with the Video Electronics Standard
Association's (VESA鈩?, Display Data Channel (DDC鈩?
standards for "Plug-and-Play" monitors. The "transmit-
only" mode (DDC1鈩? is controlled by the VCLK clock
input and the "bi-directional" mode (DDC2鈩? is controlled
by the SCL clock input, with both modes sharing a
common SDA input/output (I/O). The transmit-only mode
is a read-only mode, while the bi-directional mode is a
read and write mode following the I
2
C protocol. In write
mode the CAT24C21 features a 16-byte page write
buffer. The device is available in 8-in DIP, SOIC, TSSOP,
MSOP and TDFN packages.
PIN CONFIGURATION
DIP Package (P, L)
NC
NC
NC
VSS
1
2
3
4
8
7
6
5
VCC
VCLK
SCL
SDA
FUNCTIONAL SYMBOL
SOIC Package (J, W)
NC
NC
NC
VSS
1
2
3
4
8
7
6
5
VCC
VCLK
SCL
SDA
CAT24C21
SDA
SCL
VCC
MSOP Package (R, Z)
NC
NC
NC
VSS
1
2
3
4
8
7
6
5
VCC
VCLK
SCL
SDA
TDFN Package (RD4, ZD4)
VCLK
NC
1
NC
2
NC
3
VSS
4
8
VCC
7
VCLK
6
SCL
5
SDA
VSS
3 mm x 3 mm
Top View
PIN FUNCTIONS
Pin Name
NC
SDA
SCL
VCLK
V
CC
Function
No Connect
Serial Data/Address
Serial Clock (bi-directional mode)
Serial Clock (transmit-only mode)
Power Supply
Ground
TSSOP Package (U, Y)
NC
NC
NC
VSS
1
2
3
4
8
7
6
5
VCC
VCLK
SCL
SDA
* Catalyst Semiconductor is licensed by Philips Corporation to carry the I
2
C Bus
Protocol.
V
SS
漏 2004 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. 1032, Rev. O