One of the two important differences between voltage feedback, VFB, and current feedback, CFB, amplifiers is the capability of the CFB amplifier to produce higher slew rates than the VFB for the same quiescent current and process conditions. The other difference is the relative independence of gain bandwidth in the CFB amplifier. The VFB Op Amp is limited in slew rate by the ability of that circuit configuration to charge and discharge the inter-stage capacitor C in the voltage feedback schematic on the left-hand side. The current source I, which supplies the balancing currents to the input differential pair, is the sole source of current available to charge and discharge C when the circuit is under large signal, slew rate conditions. Since a current source supplies the same current under all conditions, charging and discharging are limited to current regardless of the magnitude of the input signal applied to the Differential Pair. In the case of the CFB amplifier on the right-hand side C equivalent, Ceq, the gain node capacitance, is charged by the balanced current sources CM which produce current IZ. By the way, CM is the abbreviation for current mirror. This becomes the charging and discharging current for C equivalent or Ceq. However, this current is not limited by the Diff Pair current source current as in the case of the VFB. Rather, this capacitance is charged and discharged by the delta current IZ supplied by the current mirror. These matched current mirrors, or CMs, are responding to the magnitude of IN which is driven by the input signal. Thus, the charging current for the equivalent capacitance, which becomes the slew rate limitation in a CFB Op Amp is proportional to the input signal and would be theoretically limited only by the size of the current mirror transistors. This is different than the VFB design architecture.