Title :
A 0.9mA 95dB ΣΔ Modulator for Digital RF Hearing Aid in 0.35μm CMOS
Author :
Chang, Long-Xi ; Li, Day-Uei ; Chung, Chi-Chen ; Shia, Tim-Kuei
Author_Institution :
Ind. Technol. Res. Inst., Hsinchu
Abstract :
A 0.9mA switch-capacitor (SC) third-order ΣΔ modulator for a digital RF hearing aid using a modified feedback loop-filter is presented. This loop-filter is composed of both feedback and feedforward paths. It has two advantages: reduced signal swings inside the ΣΔ loop and the low current consumption. With careful signal scaling, signal swings inside the loop having a -2dB reference voltage input can be suppressed to less than 95% of the reference voltage. This feature greatly enhances loop stability and current efficiency. The chip was implemented in 0.35μm CMOS process, and it achieves a dynamic range of 95dB with a signal bandwidth of 20kHz
Keywords :
σ-δ modulation; CMOS integrated circuits; biomedical electronics; circuit feedback; hearing aids; switched capacitor networks; ΣΔ modulator; 0.35 micron; 0.9 mA; 20 kHz; CMOS process; digital RF hearing aid; feedback paths; feedforward paths; modified feedback loop-filter; signal swings; switch-capacitor third-order modulator; Auditory system; Bandwidth; CMOS process; Digital modulation; Dynamic range; Dynamic voltage scaling; Feedback loop; Radio frequency; Signal processing; Stability;
Conference_Titel :
Circuits and Systems, 2007. ISCAS 2007. IEEE International Symposium on
Conference_Location :
New Orleans, LA
Print_ISBN :
1-4244-0920-9
Electronic_ISBN :
1-4244-0921-7
DOI :
10.1109/ISCAS.2007.378677
