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™), Display Data Channel (DDC™) standards for “Plug−and−Play” monitors. The “transmit−only” 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−lead DIP, SOIC, TSSOP, MSOP and TDFN packages.

Features
• DDC1/DDC2 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
• Industrial Temperature Range
• 8−lead DIP, SOIC, TSSOP, MSOP or TDFN Packages
• This Device is Pb−Free, Halogen Free/BFR Free, and RoHS Compliant