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This paper presents an energy-efficient 12-bit successive approximation-register A/D converter (ADC). The D/A converter (DAC) plays a crucial role in ADC linearity, which can be enhanced by using larger capacitor arrays. The binary-window DAC switching scheme proposed in this paper effectively reduces DAC nonlinearity and switching errors to improve both the spuriousfree dynamic range and signal-to-noise-and-distortion ratio. The ADC prototype occupies an active area of 0.12 mm 2 in the 0.18-μm CMOS process and consumes a total power of 0.6 mW from a 1.5-V supply. The measured peak differential nonlinearity and integral nonlinearity are 0.57 and 0.73 least significant bit, respectively. The ADC achieves a 64.7-dB signal-tonoise-and-distortion ratio and 83-dB spurious-free dynamic range at a sampling rate of 10 MS/s, corresponding to a peak figure-of-merit of 43 fJ/conversion-step. KEYWORDSA/D converter (ADC), binary window, D/A converter (DAC), successive approximation register (SAR)

In this brief, we demonstrate that high-quality-factor and low-power-loss transformers can be obtained if the optimized pattern ground shields (OPGS) of polysilicon is adopted and the CMOS processcompatible backside inductively coupled-plasma (ICP) deep-trench technology is used to selectively remove the silicon underneath the transformers completely. OPGS means that the redundant PGS of a traditional complete PGS, which is right below the spiral metal lines of the transformer, is removed for the purpose of reducing the large parasitic capacitance. The results show that, if the OPGS was adopted and the backside ICP etching was done, a 69.3% and a 253.6% increase in quality factor, a 10.5% and a 14% increase in magnetic-coupling factor (k Im ), a 17.2% and a 51.1% increase in maximum available power gain (G A max ), and a 0.682-and a 1.79-dB reduction in minimum noise factor (NF min ) were achieved at 5 and 8 GHz, respectively, for a bifilar transformer with an overall dimension of 230 × 215 µm 2 . Index Terms-Micromachined, optimized pattern ground shield (OPGS), power gain, quality-factor, radio frequency integrated circuits (RFICs), transformer.