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TPS659039-Q1: fail to power up (after power on and power off quickly)

Part Number: TPS659039-Q1

Hi team,

My customer use TPS659039-Q1 power for TDA2S, but they meet one issue as follows:

1. Issue background

  • The board can be started normally when it is powered on for the first time, and then it can be powered off quickly and TPS659039 has a 60% probability that it cannot output normally
  • TPS659039 specific version model O9039A385IZWSRQ1
  • A total of about 50pcs of patches, only one failure was encountered

2. Test have done

  • Measure TPS659039 input when abnormal: 5V, 3.3V input voltage is normal, RST is normal, BOOT is normal.
  • Test TPS659039 output when abnormal: LDOVRTC_OUT=1.1V (normal startup should be 1.8V); LDO2_OUT=0.2V (normal startup 3.3V); other outputs are all 0V.
  • After testing, it is determined that LDOVRTC_OUT and LDO2_OUT have fallen to 0V when the power is off, and the wrong voltage (not the residual voltage) will be output after the power is turned on again.
  • Delete R62 to ensure that LDOVRTC_OUT and LDO2_OUT are only connected to TDA2S, and the fault still exists.
  • After an exception occurs, manually reset the RST of TPS659039, and it will not return to normal.
  • After an abnormality occurs, short-circuit LDOVRTC_OUT to ground, and TPS659039 will resume normal operation 100%.
  • After an abnormality occurs, short-circuit LDO2_OUT to ground, and TPS659039 will not return to normal.
  • After checking the TPS659039 DS 6.4.11.1 chapter, pull down the 4.3K resistor on LDOVRTC_OUT, the fault still exists. And when power is off, make sure that LDOVRTC_OUT has reached 0V and then power on.

3. Support need

Could you kindly tell me how it happened and how to debug next?

Regards 

Jiawei