Title :
A 1.8-V MOSFET-only ΣΔ modulator using substrate biased depletion-mode MOS capacitors in series compensation
Author :
Tille, Thomas ; Sauerbrey, Jens ; Schmitt-Landsiedel, Doris
Author_Institution :
Inst. of Tech. Electron., Tech. Univ. Munchen, Germany
fDate :
7/1/2001 12:00:00 AM
Abstract :
A low-voltage high-linearity MOSFET-only ΣΔ modulator for speech band applications is presented. The modulator uses substrate biased MOSFETs in the depletion region as capacitors, linearized by a series compensation technique. A second-order fully differential single-loop architecture has been realized in a conventional 0.25-μm digital n-well CMOS process without extra layers for capacitors. An SNDR of 72 dB and an SNR of 77 dB is obtained with 8-kHz signal bandwidth at an oversampling ratio of 64. The circuit consumes about 1 mW from a single 1.8-V power supply and occupies a core area of 0.08 mm2
Keywords :
CMOS digital integrated circuits; MOS capacitors; compensation; low-power electronics; modulators; sigma-delta modulation; switched capacitor networks; 1 mW; 1.8 V; 8 kHz; MOSFET-only sigma-delta modulator; area efficiency; depletion region broadening; digital n-well CMOS process; high-linearity; low-voltage; second-order fully differential single-loop architecture; series compensation; speech band applications; substrate biased depletion-mode MOS capacitors; switched capacitor modulator; CMOS process; CMOS technology; Capacitance; Delta modulation; Linearity; MOS capacitors; MOSFET circuits; Speech; Switched capacitor circuits; Voltage;
Journal_Title :
Solid-State Circuits, IEEE Journal of
