AD7323 Decoupling

Hello All,

In the data sheet for the AD7323 it states: "Good decoupling is also important. All analog supplies should be decoupled with 10 μF tantalum capacitors in parallel with 0.1 μF capacitors to AGND....These low ESR, low ESI capacitors provide a low impedance path to ground at high frequencies to handle transient currents due to internal logic switching."

I read on another site (Choosing between ceramic and tantalum capacitors - 31 October 2007 - Avnet Kopp - Dataweek and the section I am referring to is a few paragraphs into 'Advantages of MLCCs' though it specifically states PSU's) that I can replace this technique of a tantalum capacitor in parallel with another smaller capacitor if I use a multilayer ceramic.

Which of these techniques ould be considered 'best practice' or recommended for this component?  Are either (or both) of these techniques antiquated?

 

Attached is the datasheet for the AD7323.

Thanks, Cam

AD7323.pdf
  • Hi Cam,

         Thank you for your question. This looks interesting topic. Capacitors are one of the common components used in the circuit designs. While there are types of capacitor exist nowadays like as what you have mentione the MLCC and tantalum.

         Most of the electronic device today uses the MLCC because of its advantages one of it is small and low ESR and ESL and many others as mentioned from the aticle from your post. The recommended 10uf tantalum capacitor and 0.1uf ceramic on the AD7323 since this combination was proven to have a good result.
         Each capacitor technology has its advantage and disadvantage. To answer your inquiry of what would be the best , I think that it need to consider what application the circuit will be use.

         Here is an article that summarizes the capacitor technology, its pros and cons. This can be your reference or may help you decide what type of capacitor technology be use for your application.

    http://www.analog.com/static/imported-files/application_notes/AN-1099.pdf

    Regards,

    Jonathan