Part Number: TPS65911
I am using the TPS6591133 to power a DM385. I am only using the VIO to power the DVDD_C, VDDA_1P8, VDDA_PCIE_1P8, VDDS_OSC0_1P8, VDDS_OSC1_1P8 of the DM385 and the DVDD of a TLV320AIC3101 audio CODEC. I have verified before getting the board booted that the VIO was 1.8V
I have had 2 boards now have the VIO go up to 3.5V even though the register setting was for 1.8V. When we tried to change it the only setting that works is 3.3V or off. Any of the other settings do nothing an the output stays at 3.5V.
I removed the output EMI filter to isolate it and see if it was the PMIC or something driving it. The output went to 4V with no load so I put a 100 OHM resistor in for a load and it still was 4V. All the other voltages are correct and can be changed.
What would cause this to happen? Any help or ideas would be great.
In reply to Jayanth Kruttiventi:
In reply to Brian Forster:
In reply to BrandonAzbell:
Can you please check when VCC6 voltage comes up. In the sequence you have sent, it looks like VCC6(3.3V) is high only after GPIO7 is high which is wrong. This would cause LDO1 and LDO2 to power up wrong.
Also can you disconnect the resistor between TPS_VDDA_1V8 net and VDDA_1V8 to check if the votlage is still shoots to 3.5V. Also, I would try to change voltages on other rails to check for feedback path between rails.
Good call on the VCC6. I am feeding it with the 3.3V that GPIO7 is turning on which explains the sequence mix up. We are trying to hack in a fix for this to see what else it might fix but I think the raised VIO voltage is a separate issue. I will post the results if we can get the board to work after our fix.
I have an EMI filter that is directly on the output of VIO that I have removed to check VIO when disconnected from the circuit. VIO actually rises to 4V when removed from the circuit.
We have successfully changed VDDctrl to 1.35V. Do you need me to try a different one?
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