Designing a Low-Noise Power Supply for Precision Sensor Project

[patrickdam]

Hello everyone,

I’m currently working on a project that involves precision analog sensors (temperature and strain gauges), and I’ve run into a challenge regarding the power supply design. The sensors require a very stable and low-noise supply; otherwise, the signal drifts and introduces measurement errors.

Here’s the situation:

The system runs primarily on a 12 V DC source.

I need to generate a clean 5 V (and possibly 3.3 V) rail for the sensors and ADC.

I tried a few switching regulators with LC filtering, but the ripple is still noticeable in the output readings.

Linear regulators help reduce noise, but efficiency and heat dissipation become a concern, especially in a compact enclosure.

My questions:

Has anyone designed a low-noise power supply specifically for sensitive analog circuits?

Would a hybrid approach (switching pre-regulator + low-dropout linear regulator) be the best compromise here?

Are there recommended regulator ICs or filter topologies that work well for this type of application?

Any PCB layout tips to minimize the coupling of noise from digital/microcontroller circuits into the analog rails?

I’d love to hear from those who have tackled similar challenges. Any suggestions, references, or even example schematics would be a huge help.

Thanks in advance for your insights!

[Magnethicc]

You said switching regulator with LC filtering is not good enough but if its ripple that is your problem then why not increase the output capacitance? why not another stage for the LC filter? (just make sure to damp them correctly).

You said LDO only solution has a heat concern but what are the losses? you need to provide more information.
if you could post your already tried solutions with schematic, values and results that could help you get more accurate responses.

If current is low enough maybe you could try the BJT capacitance multiplier circuit to reduce ripple RMS with this clever circuit.
LT has some low-noise switching regulations like the SilentSwitcher.
Switching Pre-regulator + Linear Regulator is good, tried and tested solution with commercially available products that use this topology to achieve low noise but maybe there is a simpler solutions.

[Halcyon]

OP is a previous commercial spammer/ban evader. First post made to look legit, but really, just preparing for SEO spam for a dodgy app. Tried to hide their advertising in their signature using a small/white font. Amateur hour.