670-nA CMOS OTA FOR AMLCD COLUMN DRIVER
A transconductance operational amplifier specifically optimized for a switched-capacitor LCD column driver is presented. It exploits MOS transistors in subthreshold region and dissipates 670 nA at DC. Despite this extremely low quiescent current value, the amplifier exhibits a DC gain of about 80 dB, and a gain-bandwidth product and phase margin around 2 MHz and 70 degrees, with a load capacitance of 500 fF. Besides, working in class AB, the solution provides a slew rate equal to 27V/mu s. With exception of the DC gain, these performances represent an improvement with respect to comparable solutions, and are obtained while halving the area occupation.
lcd column driver amplifier d/a converters