A very low voltage bipolar op-amp for sensor applications

A new bipolar four-quadrant operational amplifer operating at a power supply voltage of 0.8 V and with a supply current of 800 mA is here presented and illustrated. It features low input offset, low bias current, low noise, low crossover distortion and a rail-to-rail output swing. Control circuits ensuring minimum and maximum current limits for the output transistors have been incorporated. The biasing circuitry follows a PTAT scheme. A simple compensation topology allows the reduction of the area. The chip, whose area is about 2 mm(2), has been fabricated in HF2CMOS 2 mu/6 GHz technology. Finally, Spice simulations and experimental results, which confirm the expected overall performances of the low voltage op-amp, are reported.