A JFET input single supply operational amplifier with rail-to-rail output

A JFET input single supply amplifier functioning on supplies from +3 to +36 volts and 700 /spl mu/A supply current is described. The common-emitter output stage's saturation resistance of 40 ohms to the positive supply and 20 ohms to the negative supply allow rail-to-rail output voltages even with heavy load currents. An N-channel JFET folded cascode input stage provides a robust low noise front end with an input voltage range from 0.2 volts below the negative supply to 1 volt below the positive supply.