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Mitsutoshi SUGAWARA Kenji MORI Zule XU Masaya MIYAHARA Kenichi OKADA Akira MATSUZAWA
We propose a synthesis and automatic layout method for mixed-signal circuits with high regularity. As the first step of this research, a resistive digital-to-analog converter (RDAC) is presented. With a size calculation routine, the area of this RDAC is minimized while satisfying the required matching precision without any optimization loops. We propose to partition the design into slices comprising of both analog and digital cells. These cells are programmed to be synthesized as similar as custom P-Cells based on the calculation above, and automatically laid out to form one slice cell. To synthesize digital circuits, without using digital standard cell library, we propose a versatile unit digital block consisting of 8 transistors. With one or several blocks, the transistors' interconnections are programmed in the units to realize various logic gates. By using this block, the slice shapes are aligned so that the layout space in between the slices are minimized. The proposed mixed-signal slice-based partition facilitates the place-and-route of the whole RDAC. The post-layout simulation shows that the generated 9-bit RDAC achieves 1GHz sampling frequency, -0.11/0.09 and -0.30/0.75 DNL and INL, respectively, 3.57mW power consumption, and 0.0038mm2 active area.
Mitsutoshi SUGAWARA Zule XU Akira MATSUZAWA
We propose a statistical processing method to reduce the time of chip test of high-resolution and low-speed analog-to-digital converters (ADCs). For this kinds of ADCs, due to the influence of noise, conventional histogram or momentum method suffers from long time to collect required data for averaging. The proposed method, based on physically weighing the ADC, intending to physical weights in ADC/DAC under test. It can suppress white noise to 1/22 than conventional method in a case of 10bit binary ADC. Or it can reduce test data to 1/8 or less, which directly means to reduce measuring time to 1/8 or less. In addition, it earns complete Integrated Non-Linearity (INL) and Differential Non-linearity (DNL) even missing codes happens due to less data points. In this report, we theoretically describe how to guarantee missing codes at lacked measured data points.