Heat Damage to Inductors

ote:

hese boards have a common problem: an 0603 sized inductor, a Coilcraft 0603 PS-392KLB, has been damaged. Visually, they look okay, but their value is m uch too low. I've confirmed that the inductors shipped to the assembler wer e of the correct value (I measured the spares) so I'm suspecting that the a ssembler may have overheated the board and the inductors were a casualty. I would not have expected these inductors to be a weak link on the board: it seems to me that some of my other components (e.g., RF MMICs) would fail a lso, but that has not happened; only the inductors are bad.

lnerable to heat?

nd measured them out of circuit. Again, I could not see any damage but meas urements with a LCR meter showed them way out of spec. I also compared the measurements with the spare inductors in case my meter was not accurate.

's

Does not sound like the ferrite, normally the change is not dramatic

Sounds like the insulation failed on the copper wire

Cheers

Klaus

and measured them out of circuit. Again, I could not see any damage but me asurements with a LCR meter showed them way out of spec. I also compared th e measurements with the spare inductors in case my meter was not accurate.

te's

e?

n't

KRW and I concur.

Cheers, James Arthur

On Sunday, February 7, 2016 at 1:28:47 AM UTC+1, snipped-for-privacy@yahoo.com wrote :

rote:

pe and measured them out of circuit. Again, I could not see any damage but measurements with a LCR meter showed them way out of spec. I also compared the measurements with the spare inductors in case my meter was not accurate .

Pete's

ybe?

FNs

esn't

Bytheway, to catch this before full scale production, it is a good idea to run the parts through the reflow oven at standard temp, standard temp +10, standard temp +20 and standard temp +30

That combats a design that is on the limit

Cheers

Klaus