When do you have enough decoupling capacitors on your PCB?

We all struggle with creating a stable and fine-looking power supply for our IC’s and for the functionalities in our designs. High frequency noise caused by other circuit elements must be taken care of before effecting other parts of the design. Different values are used to block different frequencies. The lower capacitance, the higher frequencies it can block. In most cases we just throw a bunch of 100nF capacitors into the schematic and hope for the best. It might work, but how do you know you have the right amount and the right values?

Wouldn’t it be great to see the entire Impedance of the PCB you’re working on? To see if you are overengineering your design or not? Are the capacitors in the right place and are you using the correct values for your unique design? With CST Studio you can run this analysis repeatedly, tweaking your design until you’re satisfied.

By doing this type of simulation you will ensure that the impedance throughout the board is at an acceptable level, and you will also make sure to keep the optimal number of capacitors. It’s so easy to add way too many capacitors, but that increases both cost and production time and you still not be sure they actually do the trick or if you have the correct values.

Zellaco is the official distributor for Dassault Systemes CST Studio Suite® in the Nordic countries. Get in contact with our team of software and hardware experts for a demo or simulation of your hardware.
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