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???
05/04/06 16:20
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 		 #115595 - Answers
Responding to: ???'s previous message
Prahlad said:
Do you mean that I need to put a pi-filter in between the LDO input pin and ICL7660 inverted output?

Yes, insert a ferrite bead and some suited resistance between C12 and C13.

Prahlad said:
How do I replace C1 by a PI filter I mean the datasheet says a capacitor should be connected?

Haha! Just add a ferrite bead, suited resistance and additional cap, so that this, in combination with C1, looks like a pi-filter.

Prahlad said:
In case I connect AVcc directly to AVREF and connect a LM336-2.5 to get actual value of AVREF. How frequency is it required to read the LM336 channel. Is it ok to read the reference channel once at startup or it will be required to read reference channel every time I read my signal input and scale appropriately.

I do it every time, to cancel drift effects.

Kai

List of 42 messages in thread
TopicAuthorDate
Battery powered hand hel mixed signal            01/01/70 00:00      
   Be prepared to make a mistake            01/01/70 00:00      
      Re: Prepared to make a mistake            01/01/70 00:00      
         We're all learning            01/01/70 00:00      
   Some points...            01/01/70 00:00      
      Re: Some Points.            01/01/70 00:00      
         Answers            01/01/70 00:00      
            Re: Answers.            01/01/70 00:00      
               then...            01/01/70 00:00      
                  How much error can it cause.            01/01/70 00:00      
                     Negligible            01/01/70 00:00      
      10uH inductor + 100n            01/01/70 00:00      
         No big time delay is allowed            01/01/70 00:00      
   Modified as per suggestions.            01/01/70 00:00      
      No Cap At SV1.            01/01/70 00:00      
         Voltage drops?            01/01/70 00:00      
            Drop only 0.16V*2=0.32V            01/01/70 00:00      
               F+5V ?            01/01/70 00:00      
                  Re: F+5V & F-5V            01/01/70 00:00      
                     Good, that I aksed...            01/01/70 00:00      
                        Re: What else need changes            01/01/70 00:00      
                        why r7 to avcc.            01/01/70 00:00      
                           Ok            01/01/70 00:00      
                              Re: Capacitor with LM336            01/01/70 00:00      
                              You could do...            01/01/70 00:00      
                                 re: you could do.            01/01/70 00:00      
                                    What I meant            01/01/70 00:00      
                                       re: what i meant.            01/01/70 00:00      
                                          Present layout            01/01/70 00:00      
                                             Additionally...            01/01/70 00:00      
                              How do i connect protection diode to AVc            01/01/70 00:00      
                                 Like D3            01/01/70 00:00      
                                    Why do I need a diode.            01/01/70 00:00      
                                       credit for design            01/01/70 00:00      
                                          Thanks!            01/01/70 00:00      
                                       From ADC7-input to AVCC            01/01/70 00:00      
         Is needed            01/01/70 00:00      
            Re: Cap needed.            01/01/70 00:00      
   Modified final layouts.            01/01/70 00:00      
   I fixed your layout            01/01/70 00:00      
      Looks nice...            01/01/70 00:00      
   Design sent for PCB making            01/01/70 00:00      

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