Band-pass ΣΔ architectures with single and two parallel paths

The design strategies for band-pass ΣΔ modulators are discussed. This paper studies two different approaches: the use of resonators and the synthesis of the noise transfer function (NTF) starting from a closer function. The use of a MASH configuration to obtain multiple zeros or splitting the complex zeros of the NTF is also discussed. The sensitivity to components mismatch of the proposed solutions is studied to identify advantages and limits of various presented architectures. Results show that mismatch errors in the fraction of percent range do not degrade the SNR significantly.