Decoupling or Bypass Capacitors

[0by1]

Hello,

I have following doubts about Decoupling or Bypass Capacitors, please clarify

(1) Different b/w Decoupling or Bypass Capacitor in one line.

(2) For a MPU or any IC having 'N' Vcc (say 3V) pins how many caps i have to use ??


Thanks in advance.

 

[muthuselvam]

hi 0by1,

It is better to use separate caps for each VCC Pins.... i.e 'N' no of caps for 'N' VCC Pins...Please note that the Caps should be close to the VCC Pin of the IC.

Regards,
Muthu

 

[Pete.York]

What do you mean "one line" ?
About how many caps to use depends on the speed of your device. Usually on digital CMOS/TTL I put 100n and this is enough, some times 1n//100n . Some analog circuits require 10u,,, It all depends on application. Try using caps as it stated in datasheet.

 

[0by1]

Thanks for your reply.

What do you mean "one line" ?

I mean "explain in one line", mathematical equations:|

 

[FvM]

In usual technical terminology, bypass and decoupling capacitor are just alternate names.

 

[0by1]

Thank you FvM ,
According to me both are capacitors with different name depending on
-their frequency characteristics (diff. value)
-place where it is used.
am I right???

 

[Syncopator]

In usual technical terminology, bypass and decoupling capacitor are just alternate (sic) names.

Alternative names actually.