I'm in the process of designing a mixed signal circuit powered by USB. Power supply requirements: 0-5V and 0-3.3V for a microcontroller and an audio codec (ADC/DAC), -5V to +11.5V (ground at +5V) to an analog IC. A step-up converter boosts +5V to 11.5V I understand that between the digital and analog supply a ferrite bead filters high frequency noise. An LM137 converts 5V to 3.3V. The analog and digital ground are connected to their own ground planes. Do I need more ferrite beads for the supply rails? Is there a way to improve this circuit? Thank you for your help in advance.
Ferrite beads are only necessary in certain situations and most of those are to do with layout rather than electrical design.
Understand that by 'high frequency noise' we generally mean frequencies much higher than audible ones so they probably are not needed in your design.
Ferrite beads are only necessary in certain situations and most of those are to do with layout rather than electrical design.
Understand that by 'high frequency noise' we generally mean frequencies much higher than audible ones so they probably are not needed in your design.