Research on resonance reduction method of CQFN ceramic package

Based on the theory and full-wave electromagnetic simulation software, the resonance problem of the Ceramic Quad Flat No-lead package is analyzed. The research contents include explaining the resonance behavior of the CQFN package from the electromagnetic field theory, using the full-wave electromagnetic software to quickly find the resonance frequency, and a method of reducing resonance by adjusting the internal structure without changing the external structure of the package. For a 48-wire CQFN package with resonance frequency in the DC~8GHz frequency band, an optimized product was prepared based on the above theory and method. The test results show that the resonance point of the optimized product is eliminated. The test and simulation are in good agreement, which proves that the analysis method can be used to solve the resonance problem of the CQFN package, and is also suitable for the analysis of the resonance problem of various surface mount high-density ceramic packages.