This application note presents guidelines for circuits utilizing Linear Technology's switched-capacitor filter family. These filters are faster, quieter, and lower in distortion, making them suitable for high-performance active filter designs.
Application Note 40 presents guidelines for designing circuits using Linear Technology's switched-capacitor filter family. It explains that newer devices offer faster speeds, lower noise, and reduced distortion compared to older models, making them suitable candidates to replace complex active RC filter designs in many applications.
The document emphasizes the critical importance of proper circuit board layout, specifically highlighting issues with breadboarding techniques. It compares improperly constructed protoboards against recommended setups using copper-clad boards with ground planes and shielded cables, demonstrating significant improvements in signal integrity, noise reduction, and offset voltage.
| Total Harmonic Distortion (THD) | below –76dB |
|---|---|
| Wideband Noise | below 55μV RMS |
| Stopband Attenuation (LTC1064-1) | -72dB at 1.5 x fCUTOFF |
They eliminate resistors, allowing full implementation on a chip with inherent accuracy based on capacitor value ratios rather than absolute values.
It is a phenomenon where circuit clock artifacts feed through to the filter output, though it is rarely a problem with newer Linear Technology devices.
Improper setups like protoboards without ground planes can introduce significant noise and offset voltage, degrading performance by factors of 5 to 10 times compared to good layouts.