Can any share the knowledge on PCB mountable capacitors types and where to use which type of capacitors.
Like for decoupling we use ceramic caps & for storage we use electrolytic and tantalum caps. Can any one tell me on what basis we select the other type of capacitors like film caps(polyester, polypropylene etc)..
Hi, Bharath Gilla,
I suggest you to use DigiKey (http://www.digikey.com/) to find different surface mount capacitors.
Use tantalum capacitors and X7R for power sources, X7R capacitors for IC decoupling, C0G capacitors for analog signal processing.
Dear Rujun Chen
Thanks for reply.
Can I know why we use C0G caps for analog signal processing.Why not we use other caps like film capacitors(polyester or Polypropylene film). In which application we use them.
Also can you please tell me why we go for X7R for decoupling and C0G for analog signals circuits. what are the main difference between them
Regards
Dear Gilla,
Ceramic capacitor are the default choice in nearly anything. They're cheap, stable, widely available, compact, available in many sizes, and well resist reflow soldering temperatures.
C0G are more stable vs temperature and have better Q than X7R.
I think (but i'm not sure) that generally you can find smaller X7R than C0G for the same capacitance.
Here is an interesting comparison http://www.cde.com/resources/catalogs/ceramperf.pdf
Dear Bortolami
Thank you for your valuable information.
Can you please tell me why we use C0G caps for analog signal processing.Why not we use other caps like film capacitors(polyester or Polypropylene film).
Regards
Dear Bharath,
Polypropylene film capacitor is good choice for analog signal processing. However, it's usually not PCB mountable capacitor. Polypropylene film capacitor is much big than C0G capacitor. Polypropylene film capacitor is usually needed in condition requiring high quality capacitor with high capacitance and high voltage. Polyester capacitor is usually used in circuit for power supply.
If we consider the frequency range for analog signal conditioning. C0G capacitor is good choice if signal's frequency > 1000 Hz. Polypropylene film capacitor is used if signal's frequency < 1000 Hz.
Good luck!
Dear Gilla,
It's not necessary. If the behavior of your circuit depends on the capacitance of your capacitors you probably want more stable and precise capacitors, and thus you should coose C0G.
Maybe your analog circuit is a filter with very low requirements for precision and you don't care. In that case any ceramic capacitor will do.
It depends. As always it's a compromise between specifications, quality, price etc etc..
Thank you Davide & Rujun Chen for your information. It helped me a lot.
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