Leveraged Current Mirror Op Amp

A small change to the standard current mirror op amp configuration is shown to improve performance, with few, if any, disadvantages. Adding a pair of fixed current sources allows reduced operating-point current in the output stage, while the resulting leveraging effect increases slew rate. For equal total power dissipation, the new configuration improves DC gain and gain-bandwidth (GBW) over conventional current-mirror and folded cascode op amps, as shown by hand analyses and SPICE simulations. Also, because of increased input stage transconductance, the new configuration reduces thermal and flicker noise.