Analytical method to determine optimal out-of-band gain in multi-bit delta-sigma modulator

作者：Anand Awinash^*; Koirala Nischal; Pokharel Ramesh K; Kanaya Haruichi; Yoshida Keiji

来源：IEICE Electronics Express, 2012, 9(20): 1598-1603.

DOI：10.1587/elex.9.1598

• analog-to-digital conversion
• continuous-time delta-sigma modulator
• feedforward
• excess loop delay

A simple, systematic and deterministic MATLAB simulation which employs Risbo method and analytical simulation is proposed to determine the optimal out-of-band gain to achieve a maximal SNR and the maximum stable amplitude in a multi-bit delta-sigma modulator. Using the proposed method, a 128 MS/s, 2 MHz signal bandwidth 4th order 2-bit continuous-time delta-sigma modulator is designed and implemented in 0.18 mu m CMOS technology to verify the concept. As a result, the modulator achieves a peak SNDR of 79.3 dB and a dynamic range of 83 dB for a 2 MHz signal bandwidth (OSR = 32) while consuming only 7.8 mW from 1.8 V supply.

• 出版日期2012