What is the max freq. of normal SMD resistor and cap?

[7rots51]

0603 cap max frequency

What is the max. operation frequency of normal SMD resistors and capacitors for RF circuits?

(0805 and smallers)

Can we use them up to 2.5GHZ?

 

[rfgeek]

No sweat at 2.5 GHz and above. At these frequencies before building you are adviced to do some modeling first. Model in the parasitic inductance, capacitance to ground, and effects of pads of each component. Depends on the circuit sensitivity to the extent of modeling effort of course.

Mostly common sense but the smaller the parts the less parasitics. For instance, 0805 cap has 1.05 nH inductance while 0603 cap has 0.87 nH inductance, roughly.

Also increasing substrate hieght, i.e. distance to the ground plane, and/or lower dielectric constant εr lessens the effect of component-to-ground and pad capacitance. However via inductance increases with substrate thickness. It helps to choose a component size whose pad size is approximately the same as the 50 ohm line width.

Lots of information on the web. A couple of my favorite:
h**p://www.avxcorp.com/docs/techinfo/parasitc.pdf#search=%22avx%20parasitic%20inductance%20of%20multilayer%20capacitor%22

http://www.sigcon.com/Pubs/edn/ParasiticInductance.htm#fig

Cheers

 

[nxing]

check your manufacture's website, most of time you will find those parameter online with them.

 

[hasmir]

Based on my experience in a lot of circuits that I have made, there would be no problem in using resistors and capacitors by 2.5 GHz and even more above. ( I have used 0603 resistors by about 6Ghz and by removing their metalalization in parallel faces by above 10GHz).
But I strongly recommend that you use the smaller size (0603 instead of 0805 size).

If you have any data available or any measurement devices, for capacitors the series resonance frequency is the maximum reliable frequency that they may be used.

 

[PaulHolland]

Hi, I you do not do simulation (something that is needed above 2 GHz) you can use normal SMD 0603 capacitors upto 1 GHz, SMD 0805 some 600 MHz resistors a bit higher. These numbers are from Philips !!. The lower the value of a capacitor the higher it can go in frequency. 1 GHz is the max for 1 pF !.