I'm having some difficulty understanding the frequency response of a charge mode amplifier, circuit shown in Figure 1 below.
Figure 1: Ideal charge mode amplifier circuit (1)
I believe I understand the principles behind an charge mode amplifier circuit, however I'm rather confused about the frequency response. Considering Figure 1 above, my understanding is that R1 and Cf will act as a low pass filter, where frequencies above a specific cutoff frequency (related to values of R1 and Cf) will be attenuated. However, having had a read through a Texas Instruments (TI) PDF (2) discussing this type of circuit, the frequency response doesn't appear to follow this rule (I was expecting a low pass filter response). The circuit and frequency response described by TI is shown in Figure 2 below.
Figure 2: Practical charge mode amplifier and frequency response (2)
I'd really appreciate if someone could help me understand this.