MC34708 PMIC regulator Vcore voltage problem

[venkatesh_pvsm]

Hi,

  I was used mc4708 pmic Power management chip but i having some  problem in mc34708 VCORE(K3) voltage not came properly.

VCORE (K3)         -   0V

VCOREREF(N1)  -  1.21V

VCOREDIG(J3)   - 1.21V

VDDLP (J4)         - 3.89V

   This above voltage status were present in  our customised board of IMX537 Processor.what is the reason for VCORE voltage came 0V and how to rectify this issue.

Advance thanks,

by

Venkat

[winstonwang]

Hi Venkat,

Do you have test VSRTC?

[venkatesh_pvsm]

hello Winston

i was check VSRTC voltage level and it came 1.20V

other status are

VCORE (K3)         -   0V

VCOREREF(N1)  -  1.21V

VCOREDIG(J3)   - 1.21V

VDDLP (J4)         - 3.89V

Thanks by

Venkat

[JorgeRama_rezRi]

Hi Venkat,

That regulator should come up by default in all cases. Do you have anything connected to it? VCORE is a very low current regulator that's use as voltage reference only, it can't be used to supply any other circuitry, so if you have anything connected, you should remove it and supply it with a different regulator. Also, if you are using it as reference by placing pull-up resistors to different signals, make sure these pull-up resistors are big enough so the current consumption doesn't exceed the spec. Besides that, please also make sure the output capacitor value is the recommended one (please see latest MC34708 datasheet in the web page) and that everything is properly soldered. Is this issue happening in all of your boards? If not, the issue could be manufacturing or soldering.

Hope this helps!

Best regards.

Jorge.

[venkatesh_pvsm]

thanks for your reply i was checked my board soldering is ok .This issue is their still and their is no pull up in VCORE.