A 0.8 μm CMOS switched-capacitor video filter

The very low sensitivity properties of switched-capacitor filtering structures implemented as a parallel connection of two allpass sections has already been demonstrated theoretically and verified by computer simulation. This paper describes the design of a fifth-order low pass elliptic filter using this technique, 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 μm process. The experimental results obtained with the fabricated IC 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 μV_RMS/√(Hz), resulting in a dynamic range of 49.1 dB.