Simulation Method of SMD Capacitor Impedance in Power Distribution Network

Abstract

The invention discloses an impedance simulation method for a chip capacitor in a power-supply distribution network. The problem that the capacitor impedance is unknown and accordingly the usage is influenced is mainly solved. The impedance simulation method comprises the steps of 1 manufacturing a capacitor clamp and a calibration part; 2 using a general standard part and an electrical characteristic file of the general standard part to calibrate a vector network analyzer, measuring the electrical characteristics of the manufactured standard part and saving the electrical characteristic file; 3 using the manufactured standard part and the electrical characteristic file to calibrate a vector network analyzer and measuring a scattering parameter of the capacitor; 4 converting a reverse transmission coefficient obtained through measurement into a total impedance parameter and removing installation inductive impedance to obtain the capacitor impedance; 5 adopting a vector fitting method to performing fitting on the capacitor impedance so as to obtain a high-order expression; 6 calculating the high-order expression to obtain impedance and obtaining the impedance of the capacitor with no tag parameters. The impedance simulation method achieves accurate capacitor impedance simulation, is simple and quick and can be used for obtaining an impedance parameter of the capacitor.

Description

Technical field [0001] The invention belongs to the field of computer simulation technology, and more specifically is a simulation method for realizing the impedance of a patch capacitor through scattering parameter measurement and a vector fitting algorithm, and can be applied to the design of a power distribution network decoupling system. Background technique [0002] With the high-speed and high-density development of electronic systems, power integrity problems have become increasingly serious. The power distribution network not only needs to provide a pure and stable power supply voltage for the system, but also provides a low impedance return path for the signals in the system. Therefore, a good power distribution network is the basis for the normal operation of the system. The main decoupling component in the power distribution network is the capacitor, so capacitor simulation is the prerequisite for the design of the pre-simulation stage of the power distribution network...

AI Technical Summary

Problems solved by technology

The advantage of this simulation method is that the calculation is simple, the model is intuitive, and the simulation error is small when the parasitic resistance of the capacitor is small. The disadvantage is that the simulation error of the large capacitor is large, and the resonance point measurement is difficult when the self-resonance point of the capacitor is high.

This is due to the large package volume of large capacitors, so the parasitic inductance is large, and the bottom of the impedance curve is relatively flat. It is difficult to accurately describe the impedance characteristics of capacitors using a simple first-order RLC equivalent circuit.

At the same time, since the resonance point is usually measured with a frequency sweeper or an oscilloscope, when the resonance point exceeds the measurement bandwidth, the corresponding resistance R and inductance L cannot be calculated because the resonance point cannot be measured, and an accurate first-order RLC equivalent cannot be given. Circuit to calculate the impedance expression of a capacitor

Images