The Problem :

Switch Mode Power Supplies (SMPS) are efficient, but they often generate output noise—tiny voltage ripples that can interfere with sensitive analog circuits, sensors, or audio systems. This high-frequency noise can cause unpredictable behavior in microcontrollers or signal drift in ADCs.

The Solution :

To reduce output noise, use low ESR capacitors, ferrite beads, and LC filters at the SMPS output. A small LC filter smooths out switching spikes, while ceramic capacitors placed close to load points help suppress high-frequency noise.

Practical Example :

Imagine you’re building a precision temperature sensor project powered by a 12V SMPS. The readings jitter due to ripple noise. By adding a 47µH inductor in series and a 100µF low ESR capacitor to ground, you filter out the unwanted ripple. Your sensor now gives stable, accurate readings.

Sample Calculation :

LC cutoff frequency:

f = 1 / (2π√(L×C)) = 1 / (2π√(47µH × 100µF)) ≈ 73Hz

Perfect for filtering out high-frequency switching noise (typically >100kHz).

Product Suggestions :

Use Made in India filter parts:

• Ferrite Bead

• Low ESR Capacitor

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