TY - GEN
T1 - On improving dynamic range of wideband multistage ΣΔ modulator using nonlinear oscillation
AU - Chang, Teng Hung
AU - Dung, Lan-Rong
AU - Guo, Jwin Yen
PY - 2005/12/1
Y1 - 2005/12/1
N2 - This paper presents an improved architecture of the multistage (MASH) multibit sigma-delta modulators (ΣΔMs). The architecture can be immune to circuit nonidealities over a large portion of input range when oversampling ratio (OSR) is low, and hence the dynamic range (DR) can be improved. Our approach is based on two resonator topologies, high-Q cascade-of-resonator-with-feedforward (HQCRFF) and low-Q cascade-of-integrator- with-feedforward (LQCIFF). The key to improving DR is to use HQCRFF-based single-bit structure in the first stage and have the first stage oscillated. When the first stage oscillates, the coarse quantization noise vanishes and hence circuit nonidealities, such as finite op-amp gain and capacitor mismatching, do not cause leakage quantization noise problem. In addition, because of the in-band zeros introduced by the resonators, the proposed architecture enhances the suppression of the in-band quantization noise for wideband applications. As the results of simulation, the proposed MASH architecture can inherently have wide DR without using additional calibration techniques.
AB - This paper presents an improved architecture of the multistage (MASH) multibit sigma-delta modulators (ΣΔMs). The architecture can be immune to circuit nonidealities over a large portion of input range when oversampling ratio (OSR) is low, and hence the dynamic range (DR) can be improved. Our approach is based on two resonator topologies, high-Q cascade-of-resonator-with-feedforward (HQCRFF) and low-Q cascade-of-integrator- with-feedforward (LQCIFF). The key to improving DR is to use HQCRFF-based single-bit structure in the first stage and have the first stage oscillated. When the first stage oscillates, the coarse quantization noise vanishes and hence circuit nonidealities, such as finite op-amp gain and capacitor mismatching, do not cause leakage quantization noise problem. In addition, because of the in-band zeros introduced by the resonators, the proposed architecture enhances the suppression of the in-band quantization noise for wideband applications. As the results of simulation, the proposed MASH architecture can inherently have wide DR without using additional calibration techniques.
UR - http://www.scopus.com/inward/record.url?scp=33745452377&partnerID=8YFLogxK
U2 - 10.1109/VDAT.2005.1500085
DO - 10.1109/VDAT.2005.1500085
M3 - Conference contribution
AN - SCOPUS:33745452377
SN - 0780390601
SN - 9780780390607
T3 - 2005 IEEE VLSI-TSA International Symposium on VLSI Design, Automation and Test,(VLSI-TSA-DAT)
SP - 319
EP - 322
BT - 2005 IEEE VLSI-TSA International Symposium on VLSI Design, Automation and Test,(VLSI-TSA-DAT)
Y2 - 27 April 2005 through 29 April 2005
ER -