Title :
A 1.8 V ΔΣ modulator interface for electret microphone with on-chip reference
Author :
Bajdechi, O. ; Huijsing, J.H.
Author_Institution :
Electron. Instrumentation Lab., Delft Univ. of Technol., Netherlands
Abstract :
A ΔΣ analog-to-digital converter for voltage readout of an electret capacitor microphone is presented. The circuit works at a supply voltage of 1.8 V, suited for next generation mobile phones. An improved-linearity, single-ended high-impedance input, differential output integrator is used to read the 125 mVp audio signal and compare it with a 1-bit digital feedback. The single-loop, fourth order ΔΣ converter operates at 64 times oversampling attaining 80 dB dynamic range and a peak SNDR of 62 dB over a signal bandwidth of 11 kHz
Keywords :
circuit feedback; integrating circuits; microphones; sigma-delta modulation; telephone sets; 1.8 V; 11 kHz; audio signal; differential output integrator; digital feedback; dynamic range; electret microphone; next generation mobile phones; on-chip reference; oversampling; peak SNDR; sigma-delta modulator interface; signal bandwidth; supply voltage; voltage readout; Analog-digital conversion; Capacitors; Circuits; Delta modulation; Dynamic range; Electrets; Microphones; Mobile handsets; Output feedback; Voltage;
Conference_Titel :
Custom Integrated Circuits, 2001, IEEE Conference on.
Conference_Location :
San Diego, CA
Print_ISBN :
0-7803-6591-7
DOI :
10.1109/CICC.2001.929718
