Question on SAW filter

[abcyin]

Hi, all,

There is a performance parameter called maximum input power level of the SAW filter, I am wondering that if the input power exceeds this value, then what will happen to the SAW filter? will it be broken?

thanks in advance.

 

[davenn]

That begs the question .... How much RF power did you fed into it ? sounds like you were almost admitting that thats what you have done

it would appear ... looking at a few data sheets ... that the 15 - 20dBm is a common max power level. I would suspect if you seriously exceeded that level that the filter could be physically damaged ie. it might ***** the substrate/ceramic

Dave

did some one edit that ? did I accidentally say a word I didnt intend for public print ?
oops sorry if so

 

[biff44]

They have very fine metal fingers deposited onto the saw material. So if you exceed the RF input voltage you can either vaporize the fingers, or screw up the contact metal-to-saw material.

That said, the data sheet rating is probably for long term exposure. If you accidentally over powered the input for a few seconds, it probably survived. If you left the power on continuously for a while, it might have degraded the fingers.

Some researchy type saws (like the type deliberately made for low phase noise oscillators) have beefier fingers to handle much more RF power (see Leeson's equation!).

Rich