Dynamic push-pull operational amplifier for AMLCD common voltage driver using minimum current limiting circuit

This paper reports a Class AB output stage based on a complementary common source with a minimum current limiting circuit. The non-active transistor in the output stage remains slightly turned on to react immediately for the opposite operation. The quiescent current of the output stage is defined by the proposed minimum current limiting circuit. This operational amplifier is designed for an AMLCD common voltage driver and fabricated by MagnaChip 18V 0.35µm CMOS process. The operation range of the supply voltage is from 5V to 16V and the total quiescent current is independent of temperature variation from −40°C to 120°C. On a single 8V supply, the operational amplifier has 1.37mA quiescent current including the bias generation block. The offset voltage is measured from −3.2mV to 5.4mV for 80 samples. The maximum transient current capacity is measured 200mA. The bandwidth is 15MHz with 62° phase margin and the slew-rate is measured 29.9V/µs (rising) and 45.0V/µs (falling).