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LMK04826: The chip is hot

Jifei Chen
Prodigy 20 points
Part Number: LMK04826
Other Parts Discussed in Thread: LMK61E2

Tool/software:

Hello,

The attached are the schematic and the related PCB layout file.

Our design circuits for LMK04826 application circuits are simple, but we don't know why the chip LMK04826 on the PCBA board is very hot. We make sure that there is no Power/3.3V short to GND.

Two days ago we wrote an email to seek for tech hlep, the inquiry case is CS2529887: myTI account assistance. But it seems you didn't receive this email from our response, so we send you the tech issue again and hope you see it.

Thanks you in advance!

Jifei

  • 0 in reply to Jifei Chen
    TI__Mastermind 31510 points

    Do you have the register programming as well? May we see it?

    The layout or layout image did not make it into E2E, and we haven't received the CSC inquiry yet. Can you also please include the layout here?

    Can you confirm that the pin1 location for LMK04826 and the pin1 location for the PCB are aligned? We have occasionally seen unintentional rotation of the package by the user, which can cause extreme heating.

    ---

    Likely unrelated to the heating issue, but worth mentioning: CLKin0 is provided from the LMK61E2 oscillator, and OSCin is provided from what appears to be a 125MHz standalone oscillator. Neither CPout1 or CPout2 in your schematic snippet are connected to loop filter components, or in the case of CPout1, the 125MHz oscillator for PLL1. Is this intentional? As drawn above, the input to CLKin0 cannot ever be phase-locked to the input to OSCin, so it's not clear how the LMK61E2 would be used or needed; and PLL2 will not be able to lock in the absence of external loop filter components on CPout2.