A 25 MHz 162-output S/H analog column driver for LCDs

A circuit which is capable of driving 162 columns (150 pF/column) for RGB (red, green, blue) or monochrome LCDs (liquid crystal displays) is described. The maximum sampling frequency is 25 MHz and the power dissipation is less than 250 mW (6 V VDD and 25 MHz). The chip is implemented in a 1- mu m double-poly CMOS process, and the chip size is 50 mm/sup 2/ (25 mm/sup 2/ active area). The circuit specifications are summarized. Four drivers are implemented in a prototype black-and-white, 8-inch diagonal, 640-column LCD. At a dot frequency of 25 MHz, adjacent black and white pixels are clearly displayed without loss of gray levels (analog bandwidth is better than 12.5 MHz).<>