Decoupling caps in MMIC amplifier

[carbon9]

Hi all,

I am working with SBB-5089 MMIC amplifier from Sirenza MD. In the datasheet attached, it is shown that three decoupling caps are used as 1uF, 1200pF and CB. Could anyone explain why there are three decoupling caps?

OK, they have values of 1uF, 1200pF and CB for .05-3.5GHz application but if MMIC is operated between 4-6GHz, how can we find the right values for decoupling caps?

Also, general question is: there are different MMIC amplifirs and on their datasheets, values of coupling, decoupling caps and value and choke inductor are given without explaination. According to which formula, can we calculate the right values for inductors and capacitors of MMIC amplifiers?

Thanks,
Carbon9

 

[tanuki]

You can start here to learn the basics.

http://www.edn.com/archives/1995/090195/18df5.htm


The power decoupling network is essentially a filter. To obtain complete results will require S parameters for the capacitors (Example: **broken link removed**) and complete PCB trace and power plane characterization ... and of course a good simulator.

The short answer: Generally in most application notes, the decoupling offered as an example will be sufficient for the entire device functional range; if not there is generally a section in the datasheet providing additional information about the extended requirements.

Another reasonable article: http://www.hottconsultants.com/techtips/decoupling.html