Decoupling Capacitors

Hi guys,
How to calculate the decoupling capcitor vaules? For example, we will take an voltage measurement module. It consists of input over voltage production, amplifier(OPAMP), 12bitADC in analog section.

1. What are the values has to be used?
2. How many capacitors has to be used?
3. Placement detail?

Help me to find the answers.

By,
Vinoth. E

I'd more consider on putting an external voltage reference rather than crude VDD & VSS when dealing with AD measurements

In roughly placing a 0.1uF very closer to VDD & VSS pin is a must.

Thanks for the reply. Presently i am just following the previous design.
So i am putting the capacitors without any knowledge. I want learn the about the Decopling capacitor. so that it will be very usefull to do proper design.

If you have any study material, please share me.




Vinoth

I wouldn't call it crude to bypass any IC's power supply with a cap of 100nF.

I'd call it crude to sit in the toilette sink, pull the chain and say "Good bye, cruel world".