will PSoC be damaged?

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Anonymous
Not applicable

Test set up is : 

   

one power module (to generate 5v) generates V1 = 5V.

   

one PSoC5 (both analog and digital voltages are at V1).

   

and a input signal to PSoC at the level of (V1) *1/2. This signal comes almost simultaneously with V1.

   

Test case 1 :

   

At the begining, power module starts but due to some reason generates V1 = 2.5V and stucked.

   

Test case 2 :

   

At the begining, power module starts but due to some reason generates V1 = 1.5V and stucked.

   

Test case 3 :

   

At the begining, power module starts but due to some reason generates V1 = 2.5V and after some retry it generates 5V.

   

In all cases, will PSoC be damaged?

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7 Replies
Anonymous
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As long as the voltage at the pin is between 0V and the VCC, it should be OK. Notice there are VCC to all 4 quardants of the chip.

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ETRO_SSN583
Level 9
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You have to sequence Vdda first before Vddd if theyu are not the same.

   

 

   

GPIO are limited in spec sheet -

   

 

   

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ETRO_SSN583
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Screenshot attached.

   

 

   

Note if you violate these restrictions you can get latchup which can damage a part.

   

 

   

    

   

          http://en.wikipedia.org/wiki/Latchup

   

 

   

Regards, Dana.

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Anonymous
Not applicable

VCCD wont take long to rump up so if  Vsignal is V1*1/2 all the time then you wont have any problem as long as V1*1/2 is lower than VCCIO and  VCCIO is lower than VCCA/VCCD

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Anonymous
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 In datasheet at "DC Specifications" recommended min value of VDDA is 1.8V, that's why I put second test case.

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ETRO_SSN583
Level 9
Level 9
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Use a DSO to establish timing of ramp to see if you are violating

   

specs.

   


   

Note bulk caps like tants and electrolytics have large C tolerances,

   

influence power ramp timing, and should be trialed at tolerance

   

extremes to make sure ramp of one supply will not be in violation

   

of chip specs.

   


   

Regards, Dana.

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Anonymous
Not applicable

 pratik, if VDDA <1.8v , the PSOC might not work properly or might not work at all but it won't be damaged as long as there is no other higher voltage signal or power rail.

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