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 Associations (VESA™), Display Data Channel (DDC™) standards for "Plug-and-Play" monitors. The "transmitonly" mode (DDC1™) is controlled by the VCLK clock input and the "bi-directional" mode (DDC2™) 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 I2C 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.

FEATURES
■ DDC1TM/DDC2TM interface compliant for monitor identification
■ 400 kHz I2C bus compatible*
■ 2.5 to 5.5 volt operation
■ 16-byte page write buffer
■ Hardware write protect
■ Low power CMOS technology
■ 1,000,000 program/erase cycles
■ 100 year data retention
■ 8-pin DIP, SOIC, TSSOP, MSOP or TDFN packages
■ Industrial temperature range