A 0.8 mu m CMOS testable switched-capacitor filter for video frequency applications
This paper presents the design of a fifth-order low-pass elliptic filter that employs a parallel connection of two all-pass sections to satisfy specifications commonly used in video frequency applications. Operating with a sampling frequency of 16 MHz, the IC prototype was implemented in a standard double-poly CMOS 0.8 mu m process. The experimental verification showed a passband frequency deviation smaller than 0.08 dB up to the passband edge frequency of 3.4 MHz, and an output noise power of 0.97 mu V-RMS / root Hz, resulting in a dynamic range of 49.1 dB. The filter structure enables multiple fault detection and suits modern automated testing configurations to allow accurate estimation of the actually implemented transfer function parameters, an issue of increasing importance in VLSI circuit design. The relative area required for testing the fifth-order filter is only 8% of the total filter area, and decreases as the filter order increases.
testing switched-capacitor filters filters all-pass circuits analog integrated circuits