We are using the DLPA3005DPFD and do not require the 2.5V output from the PWR3 LDO. Because of this, we did not connect the PWR3_VIN and PWR3_OUT to anything and this has caused our system to now power up properly. We connected the PWR3_VIN to 3.3V and this now allows everything to power up. Based on the DMD Monitoring section of the datasheet, it appears as though the PWR3_VOUT is monitored and will generate an PG_Fault error if the 2.5V is not present. Is this the reason why our system was not powering up?
Is the 2.5V used internally on the DLPA?
Is there any way to ignore this PG_Fault error and allow the system to power up?
With the modification to connect PWR3_VIN to 3.3V, we will have one input capacitor that is shared between PWR3_VIN and PWR4_VIN. There is no output load on PWR3_OUT. Because there is no load, is a 10uF input cap for both PWR3_VIN and PWR4_VIN sufficient? Also, without a load, can we leave the PWR3_OUT floating and without 10uF output cap?
This mod would be limited to a small number of boards (30) and the questions I ask is to reduce the re-work and its complexity. We will re-design our board to properly connect PWR3_VIN to 3.3V with an input cap and PWR3_OUT with an output cap.