A Gm-C Filter Using Multiple-Output Linearized Transconductors

Tadashi ARAI  Tetsuro ITAKURA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E87-A   No.2   pp.384-389
Publication Date: 2004/02/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
Category: 
Keyword: 
Gm-C filter,  multiple-input transconductor,  multiple-output transconductor,  linearization,  

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Summary: 
A Gm-C filter using multiple-output transconductors suitable for reducing the chip area and power consumption is presented. The novel multiple-output transconductor is based on a translinear gain cell with a linearized input stage. Making good use of the linearized input stage, a simple common-mode feedback is also proposed for this multiple-output transconductor. Using the proposed technique, a 5th-order lowpass filter with two transmission zeros was designed and fabricated as a main part of a lowpass channel selection filter for UMTS receivers. A channel of the filter consumes 7 mA from a 2.7 V power supply and the integrated input-referred noise was 21 dBuV with 20 dB pass band gain. The proposed multiple-output technique saves roughly half the number of transconductors compared with the typical active ladder filter design. The proposed multiple-output transconductors achieve linearization and effective reduction while saving linearized input stages. They are suitable for a filter with small power consumption and small area.