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???
05/12/06 11:31
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 		 #116049 - Modified as per suggestions.
Responding to: ???'s previous message
Dear Kai,

I have modified the schematic and board layouts as per your suggestions. I am posting the modified layouts kindly have a look and post your suggestions. This is how I am deriving various supplues now.

Batt +9V ---47uF+100nF--- LM2937 ---10uF Tantallum + 10E + 470nF ---> opamp +Vcc

Batt +9V --- Pi Filter 2X47uF + 2X100nF + Ferrite Bead + 10 Ohms -- -LTC1044 [ Eqv to ICL7660 ] ---- -9V

-9V --- pi filter 47uFX2 + 100nFX2 + ferrite + 10E --- LM2990 -- 10u Tantallum + 10E+470nF --- Opamp -Vcc

Batt +9V --- Pi filter at AGND DGND crossing --- LM2937 -- 10uF tantallum -- +5V

+5V ---- 2E2 + Ferrite + 10uF Tantallum + 100nF --- Micro DVcc

+5V ---- 2E2 + Ferrite + 100nF --- Micro AVcc

img src="http://www.8052.com/users/prahlad/wcsch2.gif




Please note that LTC1044 pin 1 is for bossting the charge pump frequency which is connected to supply pin 8 of LTC1044. I have remvoed the AGND and DGND plane vias intentionally so that things can be seen clearly. I have placed vias all around the planes.

Kindly post further suggestions.

Thanks & Regards,
Prahlad Purohit



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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