Guru
Joined: 05/03/2018
Location: NetherlandsPosts: 6103
| Posted: 12:10pm 03 Nov 2025 |
Hi Peter,
This is the audio filter (similar to pico buddy) tailored to use JLC basic components. The JLC part numbers are added. The only part that is not JLC is the opamp. You can use MCP6002 for mono, and 2 MCP6002 for stereo, or a single MCP6004.
In case PAM8302 (mono 2W) you couple the 2 PWM outputs through R5 and R8 to 1 audio filter.
In case PAM8406 (stereo 5W) you have to build 2 filters, one for each L and R.
Regards,
Volhout
P.S. the picobuddy used a diode clamp between PWM and the input of the active filter. That diode clamp improves the power rail noise immunity (noise from the pico switcher). But when using a linear 3V3 power supply that may not give any improvement.
P.P.S. I did not prototype this circuit. Pure simulation. If you need me to, then I'll have to order parts first. But in essence it is (values changes) same as the picobuddy circuit.
Edited 2025-11-03 22:19 by Volhout
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