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SMPSU on 1446

Question asked by drugoimir on Jun 18, 2014
Latest reply on Feb 10, 2015 by ColemanR

Hello,

 

i've developed a multi-dsp board and it is running fine.

The point is that the 1.8V transistor used for core voltage regulation, is getting quite hot.

I've used a SOT223 device for each DSP, it is running at half its maximum dissipation capability (about 0.7W over 1.6W maximum)

and its temperature is rising about 35°C over room temperature: it is within its specifications also for tbe highest working temperature expected.

 

Now i've to design a new PCB release and, instead of using a bigger DPAK bipolar, i was curious if

i could use a small SMPSU to generate a 1.8V core voltage separately to power all DSPs.

 

My question is mostly centered if i have to follow any power-up / power-down timing procedure for the 3.3V and 1.8V lines

(eg: on power up first apply 3.3V, then apply 1.8V, for power down take 1.8V off then 3.3V....or something).

 

EDIT:

Ok, quick "datasheet tour" and first question should be cleared:

1.Power on the IC and bring it out of reset.

The order of the  power supplies (DVDD, IOVDD, and AVDD) does not matter

 

Other points? Let's cook these DSPs with a test?

 

Many thanks.

Tom

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