A Differential Sallen-Key Low-Pass Filter in Amorphous-Silicon Technology

Author

Wu, Chien-Han ; Hsieh, Hsieh-Hung ; Ku, Po-Chih ; Lu, Liang-Hung

Author_Institution

Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan

Volume

6

Issue

6

fYear

2010

fDate

6/1/2010 12:00:00 AM

Firstpage

207

Lastpage

214

Abstract

In this paper, the design and implementation of a second-order low-pass filter (LPF) utilizing an amorphous-silicon (a-Si) thin-film-transistor (TFT) process technology is presented. In order to boost the gain of the amplifiers, a positive-feedback technique is developed for the design of a differential operational amplifier (OPAMP) and a differential-difference amplifier (DDA). Based on the Sallen-Key filter structure, DDAs with the proposed gain-enhancement technique are employed for the implementation of the LPF such that the chip area and power consumption can be minimized. Using an 8 μm a-Si technology, the DDA and the LPF are realized for demonstration. Consuming a dc power of 9.5 mW from a 25-V supply, the fabricated LPF exhibits a 3-dB bandwidth of 0.3 Hz. For an input frequency of 0.3 Hz, the measured THD and SFDR are and 23.76 dB, respectively.

Keywords

amorphous semiconductors; differential amplifiers; elemental semiconductors; harmonic distortion; low-pass filters; operational amplifiers; silicon; thin film transistors; Si; THD; amorphous-silicon technology; chip area consumption; differential Sallen-key low-pass filter design; differential operational amplifier; differential-difference amplifier; frequency 0.3 Hz; gain-enhancement technique; positive-feedback technique; power 9.5 mW; power consumption; size 8 mum; thin-film-transistor process technology; voltage 25 V; Active matrix technology; CMOS technology; Circuits; Differential amplifiers; Fabrication; Frequency; Liquid crystal displays; Low pass filters; Operational amplifiers; Thin film transistors; Amorphous silicon (a-Si); Sallen-Key low-pass filter; differential-difference amplifiers (DDAs); gain-enhancement feedback; system on panel (SoP); thin-film transistors (TFTs);

fLanguage

English

Journal_Title

Display Technology, Journal of

Publisher

ieee

ISSN

1551-319X

Type

jour

DOI

10.1109/JDT.2010.2044631

Filename

5466479