Low quiescent current high speed amplifier for LCD column driver

Abstract

The design of a very low-current transconductance operational amplifier specifically optimized for a switched-capacitor LCD column driver is presented. Despite its stringent standby current requirements (lower than 700 nA), the amplifier exhibits a DC gain of about 80 dB and, working in class AB, provides a slew rate greater than 20 V/mus under a load capacitance of 500 fF. The gain-bandwidth product and phase margin are about 2 MHz and 70deg. With exception of the DC gain, these performances represent a major improvement with respect to comparable solutions, and are obtained while halving the area occupation.