<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">I don't think capacitance on the rails of the op amp will keep the output from spiking when the internal mux changes. The scope confirms this is certainly -happening-, but it's not clear to me if it actually affects the sample accuracy, or generally "matters" beyond creating unneeded transients. </div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><blockquote type="cite" class=""><blockquote type="cite" class="">my understanding is that you want to keep the thing driving the ADC input as<br class="">low impedance as possible in order to minimize the time...</blockquote></blockquote><br class=""></div><div class=""><br class=""></div><div class="">this was my understanding as well.</div><div class=""><br class=""></div><br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><b class="">Chris McDowell</b></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><a href="http://www.atxled.com" class="">ATXLED</a></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div><br class="Apple-interchange-newline"></div></div><br class="Apple-interchange-newline"><br class="Apple-interchange-newline">
</div>
<br class=""><div><blockquote type="cite" class=""><div class="">On Jul 29, 2019, at 1:02 PM, <a href="mailto:mskala@ansuz.sooke.bc.ca" class="">mskala@ansuz.sooke.bc.ca</a> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">On Mon, 29 Jul 2019, Vladimir Pantelic wrote:<br class=""><blockquote type="cite" class="">my understanding is that you want to keep the thing driving the ADC input as<br class="">low impedance as possible in order to minimize the time to charge the internal<br class=""></blockquote><br class="">Well, that's the point of including the capacitor, which will have a low<br class="">impedance at the relevant frequency. Seems to me that it'd make more<br class="">sense to put that capacitance on the op amp's power supply pins, though.<br class=""><br class="">-- <br class="">Matthew Skala<br class=""><a href="mailto:mskala@ansuz.sooke.bc.ca" class="">mskala@ansuz.sooke.bc.ca</a> People before tribes.<br class=""><a href="https://ansuz.sooke.bc.ca/" class="">https://ansuz.sooke.bc.ca/</a><br class="">_______________________________________________<br class="">Synth-diy mailing list<br class="">Synth-diy@synth-diy.org<br class="">http://synth-diy.org/mailman/listinfo/synth-diy<br class=""></div></div></blockquote></div><br class=""></body></html>