Hello, I need your help.
The problem is like this. I use a LTC3589-1 as the power supply IC for iMX536. The NVCC_SRTC_POW is supplied by LTC3589-1's LDO1. Before power up of VIO_3.3V, LDO1 is 1.3V, but after Vio is powered on as 3.3V, LDO1's voltage becomes 1.87V. Disconnect the NVCC_SRTC_POW pad and LTC3589-1's LDO1, NVCC_SRTC_POW's voltage is 1.87V, and LDO1's voltage is 1.35V. It is my first time to use LTC3589-1 as a PMIC, Is there something fault and the fault information show out through the pad?
3x for your attention.
I cut off the LT3589-1's Regulator 4 through U-boot,that is to say,there is no 3.3V power on the board,then I can measure the NVCC_SRTC_POW pad's voltage is about 0.68V.
According to your description, It seems that there exists leakage of electricity at a certain place on your baord , and the issue should be caused by 3.3V output from LTC3589.
Could you tell me the following messages about your design ?
(1)Can the board normally boot ?
(2)Can SRTC normally work ?