| Summary: | 碩士 === 國立臺灣大學 === 電子工程學研究所 === 99 === Since the life of human beings has been extended and social structure changed, biomedical application area has been fast developed and becomes a vital issue. Electrical engineers have turned their attention from consumer products to biomedical area. In order to follow this trend, we design ADCs that are suitable for biomedical application.
In this thesis, we have designed two ADCs. First, a sigma delta modulator is presented. Its structure is suitable for high-resolution application from the result of past references. We use TSMC CMOS 0.35um process. The structure is switch-capacitor second-order architecture. Target bandwidth is 22.05KHz and have sampling rate 2,56MHz, that means we have OSR of 56. Under 3-V power supply condition, the maximum SNDR is 49dB, which is about 7.8 ENOB, and achieving 54dB dynamic range. Total area is 0.98x0.68mm2 and power consumption is 3mW.
The second ADC is successive approximation ADC, the property of this circuit is low power consumption. This circuit is fabricated in TSMC 0.18um process and operates under 1-V power supply in order to save power. The target resolution is 10-bit. We use integer capacitor bridge to save chip area and maintain good capacitor mismatch. Our sampling frequency is 400KHz. Under Nyquist rate operation, maximum SNDR is 49.3dB, which is about 7.9 ENOB. Static testing performances INL is 2/-1.9 LSB and DNL is 1/-0.9 LSB. Power consumption is 9.5uW, FOM is 99fJ/conv., which is competitive among references.
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