LNK605DG output current tolerance
I have a LED driver using LNK605DG as the controller, now I have produced 5000 pcs products. I checked 24 pcs, the output power is set to 4 watts, most of them is within +/-10% tolerance, but 6 units are out the 10% tolerance, failure units listed as below:
No.: Output power(W)
#5 4.9
#10 4.6
#14 4.7
#16 2.0
#18 5.0
#22 4.7
If I replace a good LNK605 with these units, its output power will back to normal, thus, that shows no other problem on those circuit board. Does anybody know what cause the problem?
Note: I use the same load for all units testing.
Comments
Two feedback resistor values are really in 1% tolerance. I heard that the date code older than 2011 may have a wider tolerance, is that true? my device date code is "K921".
Hi
We did not change the specification of the IC, so ICs before 2011 should have the same tolerance. All parts get 100% tested to be within datasheet limits.
I saw on a response you gave that you use 1% resistors for the feedback. Can you give me your complete spec? Can you also deliver info on your transformer?
Thanks in advance.
Wesley
I made adjustment to the transformer from "PIXls Designer 8" software. what I wonder is the higher tolerance can be easyly fixed by replace an IC.
in LNK 605 the total output wattage depends upon the two feedback resistor values and its tolerance, and also the resistor placement on the pcb, please check the layout and whether the resistors are really in 1% tolerance