I am following your paper "Porrazzo, S.; Morgado, A.; San Segundo Bello, D.; Cannillo, F.; Van Hoof, C.; Yazicioglu, R.F.; van Roermund, A.H.M.; Cantatore, E., "A 155 /spl mu/W 88-dB DR Discrete-Time /spl Delta/ /spl Sigma/ Modulator for Digital Hearing Aids Exploiting a Summing SAR ADC Quantizer," Biomedical Circuits and Systems, IEEE Transactions on , vol.7, no.5, pp.573,582, Oct. 2013".

Can you suggest me the suitable reference to understand the working of the passive SC adder (Fig.4)? A reference providing the full derivation would be very helpful.