App note: Isolating analog and digital power supplies

Texas Instruments’ advice for isolating digital and analog power supplies in mixed signal circuits.

This application note recommends power supply and ground noise-reduction techniques through the use of bypass capacitors and ferrite beads in TI’s PLL-based clock distribution circuits (CDC) devices. This application note also includes a numeric  example, calculating the value of bypass and filter capacitors for a particular frequency of interest.

The article is written for PLL based clock distribution circuits, but the pointers can be applied to any mixed signal device.