An OTA-C filter for ECG acquisition systems with highly linear range and less passband attenuation*Project supported by the National Natural Science Foundation of China (Nos. 61161003, 61264001, 61166004) and the Guangxi Natural Science Foundation (No. 2013GXNSFAA019333). (May 2015)

• Record Type: Journal Article
• Authors: Duan, Jihai; Lan, Chuang; Xu, Weilin; Wei, Baolin
• Is Part Of: Journal of semiconductors. Volume 36:Number 5(2015:May)
• Page Start: 2584
• Publication Date: 2015-05
• Subjects: Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1674-4926/36/5/055006
• Languages: English
• ISSNs: 1674-4926

Abstract

<abstract> <title>Abstract</title> <p>A fifth order operational transconductance amplifier-C (OTA-C) Butterworth type low-pass filter with highly linear range and less passband attenuation is presented for wearable bio-telemetry monitoring applications in a UWB wireless body area network. The source degeneration structure applied in typical small transconductance circuit is improved to provide a highly linear range for the OTA-C filter. Moreover, to reduce the passband attenuation of the filter, a cascode structure is employed as the output stage of the OTA. The OTA-based circuit is operated in weak inversion due to strict power limitation in the biomedical chip. The filter is fabricated in a SMIC 0.18-μm CMOS process. The measured results for the filter have shown a passband gain of −6.2 dB, while the −3-dB frequency is around 276 Hz. For the 0.8 V_PP sinusoidal input at 100 Hz, a total harmonic distortion (THD) of −56.8 dB is obtained. An electrocardiogram signal with noise interference is fed into this chip to validate the function of the designed filter.</p> </abstract>