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Questions about the power up Sequencing of MCF54452(Coldfire)

Question asked by Kelben Employee on Nov 23, 2014
Latest reply on Nov 24, 2014 by TomE

I read the DS of power up Sequencing, but I still do not understand the real sequency of EVDD/SDVDD and IVDD. Which one should be first? Or let's EVDD,SDVDD and IVDD power up together? One of our customers might have this potential issue. Now customer's power is slower than 50 V/millisecond. But I need to know the real power up Sequencing. Thanks.



 

3.3 Supply Voltage Sequencing

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3.3.1 Power-Up Sequence

If EVDD/SDVDD are powered up with the IVDD at 0 V, the sense circuits in the I/O pads cause all pad output drivers connected

to the EVDD/SDVDD to be in a high impedance state. There is no limit on how long after EVDD/SDVDD powers up before IVDD

must power up. The rise times on the power supplies should be slower than 50 V/millisecond to avoid turning on the internal

ESD protection clamp diodes.

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