Nanoampere supply independent low-voltage current reference

Mixed signal integrated circuits require a form of current reference to properly bias the analog block. The use of advanced process technologies forces those circuits to operate at low voltage, and portable electronics demand operation at very low currents. Good power supply rejection is of paramount importance to reduce coupling of noise generated in the associated digital circuitry into the analog part. It is important then to count with current reference circuits that can operate with predictable performance in these conditions.