Regarding Decoupling Capacitor

[KRK]

What is a decoupling capacitor? Where is it placed? Why it should be placed near to I.C.? If the trace length is increased what is the effect?
If it is Compulsory to place a decoupling capacitor to place little far, what precautions has to be taken?

 

[Harald Kapp]

Do you know Google?
It may be easy to flood us with questions, but you should show some effort on your side. Your questions are rather basic and are explained on many a website.
One last link.

 

[KRK]

Do you know Google?
It may be easy to flood us with questions, but you should show some effort on your side. Your questions are rather basic and are explained on many a website.
One last link.

Yes. I already know about google. But these information all are theoretical based. But i need some more explanation for practical things. Thats only i asked

 

[Harald Kapp]

You're asking questions that can be answered by studying the information that's easily found on the net.
This forum is meant to help when you don't get along anymore, e.g. to explain a particular detail which you don't understand. Not to give you a crash course in electronics.

Wel'l gladly help when we see there is some effort on your side.
Currently I don't see that effort

 

[OBW0549]

What is a decoupling capacitor?

A small (usually between 10 nF and 100 nF) capacitor connected between a power pin of an IC (Vcc, Vdd, Vee, etc.) and its ground pin. In digital circuits, it acts primarily to keep the IC's supply voltage constant during logic state transitions, during which IC supply current typically spikes. With analog ICs, such as op amps, the decoupling capacitor acts to minimize power supply impedance at high frequencies, helping to prevent spurious oscillations.

Where is it placed? Why it should be placed near to I.C.?

It is placed as close to the power and ground pins as possible, to minimize the inductance of the traces connecting the decoupling capacitor to the chip.

If the trace length is increased what is the effect?

If decoupling capacitors are placed too far away from an associated digital IC, false operation (e.g., "glitches") may result. With analog ICs, the circuit may oscillate.

If it is Compulsory to place a decoupling capacitor to place little far, what precautions has to be taken?

Re-arrange things so that you do NOT have to place the decoupling capacitor far from its associated IC.

Finally, do read the tutorial linked to in HK's post #2, and heed its recommendations.

 

[KRK]

A small (usually between 10 nF and 100 nF) capacitor connected between a power pin of an IC (Vcc, Vdd, Vee, etc.) and its ground pin. In digital circuits, it acts primarily to keep the IC's supply voltage constant during logic state transitions, during which IC supply current typically spikes. With analog ICs, such as op amps, the decoupling capacitor acts to minimize power supply impedance at high frequencies, helping to prevent spurious oscillations.


It is placed as close to the power and ground pins as possible, to minimize the inductance of the traces connecting the decoupling capacitor to the chip.


If decoupling capacitors are placed too far away from an associated digital IC, false operation (e.g., "glitches") may result. With analog ICs, the circuit may oscillate.


Re-arrange things so that you do NOT have to place the decoupling capacitor far from its associated IC.

Finally, do read the tutorial linked to in HK's post #2, and heed its recommendations.

Thank a lot !!!