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</o:shapelayout></xml><![endif]--></head><body lang=FR-CA link=blue vlink=purple><div class=WordSection1><p class=MsoPlainText><span lang=FR style='mso-fareast-language:FR-CA'>Hi list,<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>I’m in the process of design for 16 bits ADC/DAC circuits.<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>This circuit will receive a 0-8vdc CV voltage, drop it down to 0-5vdc, process it through a MAX11100 16 bits ADC (reference voltage REF02 +5.00v)<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>Then process the cpu data out to a LTC2641 16 bits DAC (reference voltage REF02 +5.00v).<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>The DAC’s 0-5vdc will then be amplified back to 0-8vdc.<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>To keep as much as LSB precision I’m wondering if the voltage dividers<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>Should be fixed or adjustable..<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>See the attached schematic. The 5v to 8v amplification on the DAC section<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>Is made using U19B , R3 & R4 (<b><u>fixed</u></b> gain of 1.6)<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>And the ADC attenuation is made using U19A, R1, P1, R2. (<b><u>adjustable</u></b> attenuation of 5/8).<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>What would you use for a 16 bits ADC/DAC transfer like this ?<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'>Fixed resistor values (shown in DAC) or 2 resistors with a center trimmer (shown in ADC)?<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:#1F497D'> </span><span style='color:#1F497D;mso-fareast-language:FR-CA'><img width=815 height=614 id="Image_x0020_1" src="cid:image001.jpg@01D7021C.55BBF480"></span><span lang=EN-CA style='color:#1F497D'><o:p></o:p></span></p></div></body></html>