A very flexible BiCMOS low-voltage high-performance source follower

This paper presents a new, high performance source follower, which features very low output impedance and excellent driving capability, while only requiring a supply of one threshold plus two saturation voltages. In fact, its output conductance can be increased by a factor > 500 with a suitable local loop, making this cell suitable for driving loads up to some tenths of ohms. Using this basic block, a novel class AB push-pull operational amplifier has been designed. It achieves good performance (output quiescent current = 1.2 mu A, peak output current > 200 mu A, max. capacitive load = 1 nF), with a supply voltage of 1.3 V and a total power consumption of only 3.7 mu W.