Title :
Low-voltage high-speed switched-capacitor circuits without voltage bootstrapper
Author :
Wang, Lei ; Embabi, S.H.K.
Author_Institution :
New England Design Center, Maxim Integrated Products, North Chelmsford, MA, USA
Abstract :
Low-voltage high-speed switched-capacitor (SC) circuit design without using voltage bootstrapper is presented. The basic building block used for low-voltage SC circuit design is the auto-zeroed integrator (AZI), which can work at both low voltage and high sampling frequency. With this method, two low-voltage SC systems were successfully designed and implemented in 1.2-μm CMOS technology. The first one is a fully differential SC bandpass biquad working at 1.5 V and 5.0-MHz clock frequency. The measured Q value is 8.0 at the center frequency of 833 kHz. The second one is a fully differential fourth-order bandpass ΔΣ modulator that also works at 1.5 V and 5.0 MHz. Its measured third-order intermodulation is less than -78 dBc due to the low distortion characteristic of AZI. The measured signal-to-noise ratio of the modulator is 61 dB within the narrow band of 25 kHz centered at 1.25 MHz.
Keywords :
CMOS analogue integrated circuits; band-pass filters; biquadratic filters; delta-sigma modulation; high-speed integrated circuits; modulators; switched capacitor filters; switched capacitor networks; 1.2 micron; 1.25 MHz; 1.5 V; 25 kHz; 5.0 MHz; 61 dB; 833 kHz; CMOS technology; LV switched-capacitor circuit design; auto-zeroed integrator; delta-sigma modulator; fourth-order bandpass ΔΣ modulator; fully differential ΔΣ modulator; fully differential SC bandpass biquad; high-speed SC circuit design; low-voltage SC circuit design; voltage bootstrapper; CMOS technology; Circuit synthesis; Clocks; Distortion measurement; Frequency; Low voltage; Q measurement; Sampling methods; Switched capacitor circuits; Switching circuits;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2003.814418
