The photocircuits described in section 7.3.2 and 7.3.3 can be improved further by using a cascoding transistor in the amplifier path, to reduce the effect of the miller capacitance. The new circuits are shown in Figure 7.21. It is rather very simple to show that the small signal behavior of the circuits improves. This same principle can be used in designing the amplifiers used in these circuits for reducing the capacitance between the input and output of the amplifier.
Figure 7.21: Cascoded photocircuits.