Best 5V Input Filter for a Board with ADS1115

[muhammed12]

Hi everyone

What is the best 5V input filter circuit to reduce ripple and noise before powering a mixed-signal board with an ADC like ADS1115?

I want to clean the 5V input at the power entry point. Any recommended capacitor values, types, or LC filter suggestions?

any suggestions or example schematics are highly appreciated.

Thanks in advance

[eriksl]

If you want a very clean 5 V, I'd start with a switched mode power supply at around 7 V. If you don't have one, use a DC/DC converter to go down to 5 V. Then add a lineair voltage converter to do the last inch from 7 V to 5 V. Make sure you have enough headroom for the LVC to do it's job properly, e.g. don't feed it 5.5 V

On both sides of the LVC add both a (large) electrolytic capacitor and a small solid state capacitor (e.g. ceramic or MKT) in parallel. The second capacitor will prolong the first capacitor's lifetime considerately and it will also remove high frequency spikes better than the first.

[ahsrabrifat]

You can design a simple LC low-pass power filter designed to clean a 5V input supply.You can use A ferrite bead or inductor (L1) that blocks high-frequency interference. Two capacitors 10 µF, bulk and C2,100 nF, high-frequency bypass—shunt noise to ground at different frequency ranges. Together, they provide a stable and clean 5V output (“+5V CLEAN”) ideal for analog sections like ADCs or op-amps, improving signal accuracy and reducing digital interference. You can also see this project:

https://www.pcbway.com/project/sharepro ... S1115.html

This project is designed to amplify and measure very small voltage differences using an operational amplifier (op-amp) in conjunction with the ADS1115 analog-to-digital converter (ADC).

[muhammed12]

If you want a very clean 5 V, I'd start with a switched mode power supply at around 7 V. If you don't have one, use a DC/DC converter to go down to 5 V. Then add a lineair voltage converter to do the last inch from 7 V to 5 V. Make sure you have enough headroom for the LVC to do it's job properly, e.g. don't feed it 5.5 V

On both sides of the LVC add both a (large) electrolytic capacitor and a small solid state capacitor (e.g. ceramic or MKT) in parallel. The second capacitor will prolong the first capacitor's lifetime considerately and it will also remove high frequency spikes better than the first.

Thanks for the clear explanation

[muhammed12]

You can design a simple LC low-pass power filter designed to clean a 5V input supply.You can use A ferrite bead or inductor (L1) that blocks high-frequency interference. Two capacitors 10 µF, bulk and C2,100 nF, high-frequency bypass—shunt noise to ground at different frequency ranges. Together, they provide a stable and clean 5V output (“+5V CLEAN”) ideal for analog sections like ADCs or op-amps, improving signal accuracy and reducing digital interference. You can also see this project:

https://www.pcbway.com/project/sharepro ... S1115.html

This project is designed to amplify and measure very small voltage differences using an operational amplifier (op-amp) in conjunction with the ADS1115 analog-to-digital converter (ADC).

Thanks for the practical filter idea and the project link!