Title :
A 1-V 13-mW Single-Path Frequency-Translating
Modulator With 55-dB SNDR and 4-MHz Bandwidth at 225 MHz
Author :
Chopp, P.M. ; Hamoui, Anas A.
Author_Institution :
Dept. of Electr. & Comput. Eng., McGill Univ., Montreal, QC, Canada
Abstract :
This paper presents a frequency-translating bandpass ΔΣ modulator that uses single-path mixing within the ΔΣ feedback loop to downconvert a 4-MHz signal band from IF1 = 225 MHz at the input to IF2 = 25 MHz at the output. The proposed ΔΣ modulator is designed with a sixth-order continuous-time loop filter and a 3-bit quantizer. The quantizer operates at a sampling frequency of 100 MHz, which is lower than IF1 and, therefore, reduces both the power consumption and the sensitivity to timing errors relative to a conventional bandpass ΔΣ modulator. Furthermore, the loop filter implements noise shaping primarily at IF 2, which reduces the sensitivity to coefficient variations. The prototype chip was fabricated in 65-nm CMOS with an active area of 0.55 mm2. It achieves an SNDR of 55 dB over a 4-MHz signal bandwidth, and consumes 13 mW from a 1-V power supply.
Keywords :
CMOS digital integrated circuits; continuous time filters; delta-sigma modulation; quantisation (signal); ΔΣ feedback loop; 3-bit quantizer; CMOS technology; conventional bandpass ΔΣ modulator; frequency 100 MHz; frequency 225 MHz to 4 MHz; noise shaping; power 13 mW; power consumption; sampling frequency; single-path frequency-translating ΔΣ modulator; single-path mixing; sixth-order continuous-time loop filter; size 0.55 mm; timing errors; voltage 1 V; Frequency modulation; Mixers; Noise; Receivers; Sensitivity; Topology; Analog-to-digital conversion; bandpass; continuous-time; frequency translation; multibit; sigma-delta ($Sigma Delta$) modulation;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2012.2227611