High-frequency noise in boost DC-DC converters is a common pain point for industrial automation and electronic equipment manufacturers. It not only affects the stability and reliability of your products but also risks failing EMC certifications—delaying time-to-market and increasing development costs. As a trusted PCBA manufacturer specializing in industrial-grade solutions, we’ve helped hundreds of small and medium-sized enterprises (SMEs) resolve noise issues and deliver high-performance, compliant products. In this guide, we’ll share proven methods to suppress high-frequency noise in boost DC-DC converters, along with how our custom PCBA services can simplify your design and manufacturing process.
Boost DC-DC converters are widely used in industrial automation, telecom equipment, and power supply systems, but their high-speed switching operations often generate unwanted high-frequency noise. Left unaddressed, this noise can disrupt sensitive components, damage equipment, and lead to costly reworks. Below are practical, actionable strategies to mitigate this challenge—tailored for industrial applications where reliability and performance are non-negotiable.
1. Reduce Resonant Energy and Inductance to Lower High-Frequency Noise
To cut down high-frequency noise, the first step is to reduce the energy that causes ringing when the low-side switch turns ON/OFF. LC resonance occurs when energy transfers between inductive and capacitive components—eliminating either component would prevent resonance, but that’s not feasible in practical designs. Instead, reducing the inductance of the output loop minimizes stored energy, thereby suppressing LC resonance and high-frequency noise. Our PCBA engineering team optimizes inductor selection and loop design during the early stages to proactively reduce noise sources.
2. Improve Turn-On Speed and Minimize Reverse Recovery Current
To reduce ringing energy when the low-side switch turns OFF, minimize the overshoot of the switch node voltage (VSW). For faster turn-on of the high-side switch, choose high-speed diodes with minimal turn-on delay. When it comes to reducing ringing during low-side switch turn-on, minimizing reverse recovery current is key.
For diode rectification with low output voltage, Schottky barrier diodes (SBDs) are ideal. Unlike PN-junction silicon diodes, SBDs do not use holes for rectification, so no reverse recovery current flows. They also have a lower forward voltage (VF) than silicon diodes, boosting efficiency. However, SBDs have higher leakage current under reverse bias, so thermal runaway must be prevented when used at high output voltages and high temperatures.
For output voltages up to several hundred volts—where SBDs are impractical due to reverse voltage and thermal issues—fast recovery diodes (a type of silicon diode) are a better choice. They have small reverse recovery current, and while their VF is higher than ordinary silicon diodes, the impact on efficiency is minimal at high output voltages.
In synchronous rectification, the high-side switch FET has a parasitic diode that cannot be removed. This parasitic diode acts like a PN-junction silicon diode with poor performance, and current flows through it during dead time. Our PCBA design experts minimize dead time and optimize gate drive timing to reduce current through the parasitic diode, minimizing turn-on delay and reverse recovery current.
3. Minimize Inductance in the Output Loop
When the high-side switch turns ON, high-speed pulse current flows into the output capacitor. However, the equivalent series inductance (ESL) of the output capacitor generates back EMF, creating pulsed high voltage in the capacitor. The subsequent current stores magnetic energy in the ESL, which becomes a source of resonance. Choosing output capacitors with low ESL reduces the peak pulse voltage and stored energy, suppressing resonance and high-frequency noise.
Boost DC-DC converters require high-voltage, high-capacity capacitors, which are often physically large and hard to find with low ESL. In such cases, we recommend paralleling N capacitors each with 1/N capacity instead of using a single large capacitor. This reduces ESL by minimizing each capacitor’s size and further lowers ESL to 1/N through parallel connection. While effective, this method increases component costs with more capacitors—our PCBA team balances performance and cost to find the optimal solution for your project.
Adding small-capacity ceramic capacitors also reduces ESL in the output loop. High-speed current fluctuations in the output capacitor (lasting ns to tens of ns) when the high-side switch turns ON carry only about 100nC of charge at a few amps. Even small capacitors (below 1μF) with low ESL can handle this charge without significant voltage rise. For low-capacity power supplies, we suggest placing a ~0.1μF small ceramic capacitor between the high-side switch output and low-side switch ground, keeping the distance as short as possible to bypass the output capacitor’s high ESL and minimize loop inductance.
Figure 1Minimize Inductance
4. Minimize Output Loop Area Through Component Placement and Layout Design
ESL of the output capacitor accounts for the largest portion of inductance in the output loop. Paralleling small ceramic capacitors drastically reduces ESL-induced inductance, but PCB traces connecting components also generate inductance, and the output loop itself acts as an inductor. Minimizing trace length between components reduces trace-induced inductance.
Loop inductance is proportional to loop area, so component layout should prioritize minimizing this area. Expanding trace width to fill the loop space further reduces loop area. Additionally, resonant current in the output loop creates high-frequency changing magnetic fields, which can propagate as EMI (Electromagnetic Interference) and spread noise. The strength of these magnetic fields is also proportional to loop area—minimizing loop area not only reduces noise but also cuts down radiated EMI, making it a critical noise suppression measure.
Figure 2Minimize Output Loop Area
5. Add LC Filters for Unavoidable Resonance
Resonance cannot be eliminated entirely: the output capacitance (COSS) of the low-side switch FET and output loop inductance can never be zero, and switch turn-on/off speeds are getting faster. To prevent high-frequency noise from propagating to the load circuit, insert an LC low-pass filter in the power output line.
This LC filter uses ferrite beads (effective for eliminating noise in the hundreds of MHz range) and 1000pF small ceramic capacitors (with low ESL in the same frequency range). Ferrite beads are particularly effective: their impedance at high frequencies is mostly resistive, dissipating high-frequency energy as Joule heat to suppress noise.
At our PCBA manufacturing facility, we integrate these noise suppression strategies into every stage of design and production—from component selection and PCB layout to prototyping and testing. Our team of experts specializes in industrial PCBA solutions, offering custom PCB design, prototype assembly, small-batch and high-volume manufacturing, and turnkey services. Whether you’re struggling with high-frequency noise in boost DC-DC converters or need a reliable partner to bring your industrial electronic product to life, we have the expertise and capabilities to deliver compliant, high-quality PCBA solutions that meet your deadlines and budget.
Stop letting high-frequency noise derail your projects—partner with us for your next PCBA order and experience seamless design, reliable manufacturing, and exceptional support.
Figure 3Add LC Filters
