A CBSC second-order sigma-delta modulator in 3μm LTPS-TFT technology

Author

Lin, Wei-Ming ; Lin, Chan-Fei ; Liu, Shen-Iuan

Author_Institution

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

fYear

2009

fDate

16-18 Nov. 2009

Firstpage

133

Lastpage

136

Abstract

A second-order sigma-delta modulator has been implemented in 3 μm low-temperature poly-silicon thin-film transistor (LTPS-TFT) technology. Since the LTPS-TFT operational amplifier has a low open-loop gain, a large offset voltage, and the poor linearity, the proposed comparator-based switched-capacitor integrator with correlated double sampling is adopted in the modulator. The whole modulator consumes 63.3 mW from an 11.2 V supply and occupies 26 mm² area. In a signal bandwidth of 1.56 kHz for the touch panel application, the measured input dynamic range is 69 dB and the measured peak signal-to-noise plus distortion ratio is 65.63 dB with the duty-cycle control technique.

Keywords

elemental semiconductors; modulators; silicon; thin film transistors; CBSC second-order sigma-delta modulator; LTPS-TFT operational amplifier; comparator-based switched-capacitor; duty-cycle control technique; signal bandwidth; signal-to-noise plus distortion ratio; Bandwidth; Charge transfer; Circuits; Delta-sigma modulation; Distortion measurement; Linearity; Operational amplifiers; Sampling methods; Thin film transistors; Threshold voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Solid-State Circuits Conference, 2009. A-SSCC 2009. IEEE Asian

Conference_Location

Taipei

Print_ISBN

978-1-4244-4433-5

Electronic_ISBN

978-1-4244-4434-2

Type

conf

DOI

10.1109/ASSCC.2009.5357196

Filename

5357196