Introduction
The Integrated Circuit Systems ICS90C65 is a dual clock generator for VGA applications. It simultaneously generates two clocks. One clock is for the video memory, and the other is the video dot clock.

Description
The Integrated Circuit Systems Video Graphics Array Clock Generator (ICS90C65) is capable of producing different output frequencies under firmware control. The video output frequency is derived from a 14.318 MHz system clock available in IBM PC/XT/AT and Personal System/2 computers. It is designed to work with Western Digital Imaging Video Graphics Array and 8514/A devices to optimize video subsystem performance.

Features
• Specified for dual voltage operation (VDD=3.3V or 5V), but operates continuously from 3.0V to 5.25V
• Designed to be powered-down for extended battery life
• Backward compatibility to the ICS90C64 and ICS90C63
• Dual Clock generator for the IBM-compatible Western Digital Imaging Video Graphics Array (VGA) LSI devices, and 8514/A chip sets
• Integral loop filter components, reduce cost and phase jitter
• Generates fifteen video clock frequencies (including 25.175 and 28.322 MHz) derived from a 14.318 MHz system clock reference frequency
• On-chip generation of eight memory clock frequencies
• Video clock is selectable among the 15 internally generated clocks and one external clock
• CMOS technology
• Available in 20-pin PLCC, SOIC and DIP packages