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???
12/04/12 20:14
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 		 #188964 - (dV/dt) examples
Responding to: ???'s previous message
Richard Erlacher said:

I'm still anxious to find some sort of specification that actually sets a minimum on safe rise and fall of the positive supply to 805x-core MCU's.


You will not find a generic spec, but I have found this example
in the NXP P89LPC970/971/972 data
www.nxp.com/documents/data_sheet/P89LPC97X.pdf


(dV/dt)r rise rate of VDD; to ensure power-on reset signal 5 - 5000 V/S
(dV/dt)f fall rate of VDD - - 50 mV/μs
VPOR power-on reset voltage - - 0.5 V

That VPOR spec I guess is without the BrownOut detector operating ?

I have found a useful reality(stress) test is to feed a Signal Generator into the control pin of a LM317 thru a resistor.

Using Freq and DC offsets on the generator, you can generate ANY Vcc dip you want to, and some devices really do not like the 1-2V region, as a MinVcc
( so you can see where that Vpor 0.5V comes from )


Richard Erlacher said:

Without a manufacturer's specification, we're all on our own.


Even with it, you are still on your own ;)

List of 33 messages in thread
TopicAuthorDate
C8051F231 experiences            01/01/70 00:00      
   another solution            01/01/70 00:00      
   The probabilities are low...            01/01/70 00:00      
      think about what happens when you add a finger            01/01/70 00:00      
         The point is ...            01/01/70 00:00      
            Yes ... the underlying issue is the flash ...             01/01/70 00:00      
               Out of my office, but...            01/01/70 00:00      
                  Don't think in Vcc, ESD or hum...            01/01/70 00:00      
   Apparently several C8051F2xx parts have the same pinout            01/01/70 00:00      
   Characteristic for in system programmable flash micros...            01/01/70 00:00      
      All too true ... sadly ...             01/01/70 00:00      
         Power-on slope rate...            01/01/70 00:00      
            Sorry, my post should be here, no up there...            01/01/70 00:00      
            Have you any basis for that rate?            01/01/70 00:00      
               Vdd ramp time            01/01/70 00:00      
               Some datasheets show numbers...            01/01/70 00:00      
                  Those aren't the "usual" 805x-core MCU's            01/01/70 00:00      
                     There aren't many "usual" 8051-cores anymore...            01/01/70 00:00      
                        How dangerous power ups can be...            01/01/70 00:00      
                           I believe it            01/01/70 00:00      
                              (dV/dt) examples            01/01/70 00:00      
                                 They don't know it either...            01/01/70 00:00      
                                    dV/dT etc             01/01/70 00:00      
                                       reset request...            01/01/70 00:00      
                                          That's what disturbs me greatly            01/01/70 00:00      
                                             It IS disturbing!            01/01/70 00:00      
                                                Where this began ... at least for me ...             01/01/70 00:00      
                                                   So, you took the hard road...            01/01/70 00:00      
                                                      We've all had that experience             01/01/70 00:00      
   probable cause            01/01/70 00:00      
      Brent, this is very nice            01/01/70 00:00      
         forum no longer down            01/01/70 00:00      
      Thank you!            01/01/70 00:00      

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