emmanuel63
Well-known member
Hi,
I have been using pam8304 class D amp for many of my projects. This amp delivers a lot of power from 5V.
But it is a pain to reject noise. Digital noise tends to leak in power rails (I think).
I would like to know what are the best practices to limit digital "leaks". I need advices for :
- PCB ground planes design
- power rails design
- decoupling
- and also advices to avoid ground loops
I join the schematic of a little synth project. It works "as is" pretty well, but I would like to improve noise rejection.
I would appreciate comments about this schematic, and advices to get a well designed PCB. I use a Teensy 4.0, an i2s dac (uda1334) and a pam8302.
The red dots on the schematic are capacitive pads, for notes triggering.
I use a resistive ladder to add a lot of switches with only 1 input. It is working well, no problem on this side.
Pots readings are noisy. Digital noise leaks again. Some analog inputs are almost free of noise, others are very noisy (+- 10 on 1024). But it is ok with basic filtering.
Thank you,
Emmanuel
View attachment Schematic_MiniTouch.pdf
I have been using pam8304 class D amp for many of my projects. This amp delivers a lot of power from 5V.
But it is a pain to reject noise. Digital noise tends to leak in power rails (I think).
I would like to know what are the best practices to limit digital "leaks". I need advices for :
- PCB ground planes design
- power rails design
- decoupling
- and also advices to avoid ground loops
I join the schematic of a little synth project. It works "as is" pretty well, but I would like to improve noise rejection.
I would appreciate comments about this schematic, and advices to get a well designed PCB. I use a Teensy 4.0, an i2s dac (uda1334) and a pam8302.
The red dots on the schematic are capacitive pads, for notes triggering.
I use a resistive ladder to add a lot of switches with only 1 input. It is working well, no problem on this side.
Pots readings are noisy. Digital noise leaks again. Some analog inputs are almost free of noise, others are very noisy (+- 10 on 1024). But it is ok with basic filtering.
Thank you,
Emmanuel
View attachment Schematic_MiniTouch.pdf