A large dynamic‐range, high dB‐linearity VGA using switch arrays and second‐order mismatch‐shaping DEM technique. (26th May 2015)

• Record Type: Journal Article
• Authors: Li, Di; Yang, Yintang; Shi, Zuochen; Jing, Zhan
• Is Part Of: International journal of circuit theory and applications. Volume 44:Number 3(2016:Mar.)
• Page Start: 693
• Page End: 708
• Publication Date: 2015-05-26
• Subjects: variable gain amplifier -- dynamic element mismatching -- mismatch shaping -- thermometric decoding -- cascade structure -- linearity; Electric circuit analysis -- Periodicals; 621.319205
• DOI: 10.1002/cta.2101
• Languages: English
• ISSNs: 0098-9886

Abstract

Summary: A new large dynamic‐range variable gain amplifier (VGA) with improved dB linearity is presented. The traditional cascade VGA has the disadvantages of gain mismatch between sub‐stages and difficulty of employing mismatch cancelation or suppression algorithms. In this paper, switch arrays were used to make the sub‐stages or called gain cells in the coarse‐tuning stage (CTS) work independently and therefore prevent the integral operation of the gain errors. Then, a second‐order mismatch‐shaping DEM was applied conveniently to the CTS and shown to be a useful design technique in improving the dB‐linearity performance. The cascade VGA and its second‐order mismatch‐shaping DEM had been integrated in a 2.4‐GHz receiver chip which was fabricated in a 0.18‐µm CMOS technology with a supply voltage of 1.8 V. Measurement results showed that the gain errors were significantly reduced with second‐order mismatch‐shaping DEM with respect to the traditionally thermometric decoding over a temperature range of [−40, 80] °C. Copyright © 2015 John Wiley & Sons, Ltd. Abstract : The traditional cascade VGA has the disadvantages of gain mismatch between sub‐stages and difficulty of employing mismatch cancelation or suppression algorithms. In this paper, switch arrays were used to make the sub‐stages or called gain cells in the coarse‐tuning stage (CTS) work independently and therefore prevent the integral operation of the gain errors. Then, a second‐order mismatch‐shaping DEM was applied conveniently to the CTS and shown to be a useful design technique in improving the gain dB‐linearity performance.