Offset-compensated low power current comparator

A new current comparator based on a folded-cascade amplifier is presented. It has an excellent sensitivity of 20 nA and provides offset compensation avoiding clock-feedthrough errors. The circuit dissipates only 30 μW and achieves a switching time better than 30 ns with a 0.5 μA input step current. Moreover, the bias current and the input impedance are well-controlled parameters