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Power Sequence on LS1012A Dev Board(XFRWY-LS1012A-PA)

Question asked by Joe Lindula on Mar 1, 2019
Latest reply on Mar 4, 2019 by Joe Lindula

Hello, I am curious how the power up sequence on the LS1012A board is done. I see there are two power devices the MC34713P that generates the 3.3V. It looks like that comes up as soon as the 5V is applied. I also see the MC34VR5100 which powers the 0.9V, 1.8V and the 1.35V.  I don't see where the VLDO2 1.55V is generated can you please help me find that?

 

Now onto the control of the sequencing, how is the VR5100 setup to delay the power on of the 2.5V and the 0.9V? I understand that is has an I2C interface but that is to the LS1012A and that can't program it until it is powered up. Is the VR5100 programmed before it is placed on the PCB?

 

Thank you,

Joe

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