DocumentCode :
82471
Title :
A 64-fJ/Conv.-Step Continuous-Time 
Modulator in 40-nm CMOS Using Asynchronous SAR Quantizer and Digital  with 6-bit asynchronous successive approximation register (ASAR) quantizer and digital ΔΣ truncator for WCDMA/GSM/EDGE cellular systems is presented. The proposed ASAR-based quantizer reduces the area and power of the modulator dramatically by utilizing the digital truncation technique. By using the 6-bit ASAR quantizer, the sampling frequency is lowered, which reduces the design efforts not only in system level but also in the modulator. In addition, the ac-coupled push-pull stage is employed to improve the high-frequency driving capability of the first integrator. Sampling at 65 MHz, the modulator achieves 83.4 dB dynamic range (DR) and 80/79.6 dB peak SNR/SNDR with 1.92 MHz bandwidth in WCDMA mode. In GSM/EDGE mode, the DR is 96.2 dB. Fabricated in 40-nm CMOS, the modulator occupies 0.051 mm <sup>2</sup> and consumes 1.91 mW from a 1.2-V supply. A 64fJ/conv.-step figure of merit is achieved.</div>
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<div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Keywords : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>CMOS integrated circuits; asynchronous circuits; cellular radio; code division multiple access; continuous time systems; coupled circuits; sigma-delta modulation; CMOS; WCDMA-GSM-EDGE cellular systems; ac-coupled push-pull stage; asynchronous SAR quantizer; digital truncation technique; digital truncator; frequency 65 MHz; high-frequency driving capability; power 1.91 mW; size 40 nm; successive approximation register; third-order single-loop continuous-time sigma-delta modulator; voltage 1.2 V; Delays; Frequency modulation; GSM; Multiaccess communication; Noise; Spread spectrum communication; AC-coupled push-pull; EDGE; GSM; WCDMA; asynchronous successive approximation register (ASAR); continuous-time sigma–delta modulator (CTSDM); digital <formula formulatype=)
$Delta Sigma$ truncator; dynamic element matching (DEM); low sampling frequency;
fLanguage :
English
Journal_Title :
Solid-State Circuits, IEEE Journal of
Publisher :
ieee
ISSN :
0018-9200
Type :
jour
DOI :
10.1109/JSSC.2013.2274852
Filename :
6578611
Link To Document :
