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Decoupling capacitor... how to?

@xi@g@me

Dec 15, 2016
86
Joined
Dec 15, 2016
Messages
86
Hell all, again :)

Since I started learning digital electronics, I rapidly went into the notion of decoupling capacitor. I understand that the role of such a capacitor is to prevent the power supply of protected chip from rapid voltage changes due to internal usage of said chip, because usually power supply electronics are not able to adapt fast enough.

First time I had to use it, I asked a colleague who told me to simply use a pair of capacitors, one non-polarized (ceramic) with small capacity, and another polarized (electrolytic) with more capacity (around 10x more), which worked fine for me. However, a question remains. How should I calculate the needed values? If I want to use a more sensible IC, I may need to know which capacitors to use!

For example, in this schematic, the GL850G chip is protected by many decoupling capacitors (and even a coil, dunno the purpose of it). The datasheet (and design guidelines document, in Chinese), do not state at all which decoupling capacitors to use.

In a further research, I found this topic on stack exchange. The large answer gives a piece of information about different profiles and how they select decoupling capacitors, but with no specific answer. An other answer states that I should "Find or estimate the amount of the max current and max time that the load will take its 'excursion' from the nominal value of the voltage rail.".

The question is: how do I get this information? Is there a step by step method to get such information and search for the best suited decoupling capacitor? Is it really needed for hobbyist electronics, or too complex to be needed or treated by an amateur as me?
 

@xi@g@me

Dec 15, 2016
86
Joined
Dec 15, 2016
Messages
86
Thanks, I'll have a look there. The topic seems quite resourceful :)
 
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