Figure 15. (a) Transistor-level schematic, (b) half-circuit representation of the schematic, (c) gmC equivalent circuit, and (d) smallsignal diagram of the cross-coupled source-follower-based BPF [35]. Hs − XSFBPF ()=⋅ C C IN F ++ ss 2 11 2 2 g C mm m IN gg C IN s g C m1 IN ω0 = gg C mm Q = IN 12 g g m m 2 1 (22) where iZ represents a small-signal current in Fig. 15(c), CL is a load capacitance of the CCIA. We assume CC LF and sg C CC CFF /2 IN mF3 / () from the original OTA bandwidth as also described in [31]. The second apfor the first apHs Hs X Hs proximation in (25). We can see that the bandwidth of CCIA is reduced by the amount of feedback factor β=+ gCm3 /,L proximation used in (25) is valid when the bandwidth of CCIA is sufficiently higher than ω0 in the BPF. The transfer function of the XSF-based BPF Hs rived in (22) using the equations as below. Hs == IN. BPF () is deLPF () can be found in (18) but with an additional condition of CC C12 40 IEEE CIRCUITS AND SYSTEMS MAGAZINE () = LPF Loss = s Hs IN mF2 C g LPF ()⋅ C C BPF () =() ()CCIA IN X () Hs HsLPF () − (26) A clear advantage of the SF-based filters over the OTA-based design is its minimal number of parasitic poles. As shown in Fig. 12(a), the XSF filter exploits every node within the circuit as a source for pole synthesis while the OTA-based circuit does not. For instance, the mirror pole in the OTA acts as a non-dominant pole thereby necessitating additional power dissipation to SECOND QUARTER 2023 () Hs Hs =Hs s y () LPF () + 1 C g IN m2