smd 0402 layout

Hi, No problem. 0805 work OK upto 1.5 GHz for low value capacitors, resistors is also no problem. 0603 is upto 3 GHz and 0402 some 5.5 GHz.

Paul.

As PaulHolland said there is no problem.
Only if is any critical component you must know that the reactance of the component change.

I think the 0805 inductor have higher Q value than 0402 one.
So no problem for inductor.

Could anyone please help me explaining that how does the performance varies with varying component sizes as mentioned above?

Shoaibali what exactly do u need?

David

hi,

There is non problem if you change your component size but you have to take carea of your RF layout in such a mannaer that it does not aid spurious emissions which would interfere with your circuit . Norm,ally it is advisable not o change your component size

Added after 27 seconds:

hi,

There is non problem if you change your component size but you have to take carea of your RF layout in such a mannaer that it does not aid spurious emissions which would interfere with your circuit . Normally it is advisable not to change your component size

For capacitors, the larger the part, the more inductance, which means a lower self resonance. Also means more pad area which means more shunt capacitance. Smaller capacitors need either a higher Er dielectric or thinner layers which means a higher breakdown material. The tradeoff to these properties is a higher loss tangent so the Q is reduced.

It's similar for inductors. Larger air-core parts will have high Q but usually have a lower self resonance due to inter-winding capacitance. As the size decreases they are wound on a ferrite core which yields a lower Q, but now you have less capacitance so a higher SRF. This is why the 0603 parts usually have higher Q than 0402, but lower SRF.

I still like to go with 0402 since the higher SRF and layout density usually outweigh the lower Q, which is not lower by much. It's pretty cool that all these miniature components (i.e. 0201 wire wound inductors) allow lumped element designs well into the microwave region, something you could not get away with in the past.

Many thanks everyone for your replies and knowledge sharing...