GENERAL DESCRIPTION
The Philips PCB2421 is a 128 × 8-bit dual mode serial Electrically Erasable PROM (EEPROM).
This device is designed for use in applications requiring storage and serial transmission of configuration and control information. Two modes of operation have been implemented: transmit-only mode (DDC1 mode) and bidirectional mode (DDC2B, or I2C-bus mode). Upon power-up, the device will be in the transmit-only mode, sending a serial bitstream of the entire memory array contents, clocked by the VCLK pin. A valid HIGH-to-LOW transition on the SCL pin will cause the device to enter the bidirectional mode, with byte selectable read/write capability of the memory array. The PCB2421 is available in a standard 8-pin dual in-line and 8-pin small outline package operating in a commercial temperature range.

FEATURES
• Single supply with operation 4.5 to 5.5 V
• Completely implements DDC1/DDC2B interface for monitor identification
• Low power CMOS technology
• Two-wire I2C-bus interface
• Self-timed write cycle (including auto-erase)
• Page-write buffer for up to 8 bytes
• Write-protect pin
• 100 kHz I2C-bus compatibility
• Designed for 10000 erase/write cycles minimum
• Data retention greater than 10 years
• 8-pin DIP and SO package
• Temperature range 0 to +70 °C.