<HTML><FONT FACE=arial,helvetica><HTML><FONT SIZE=2 PTSIZE=10 FAMILY="SANSSERIF" FACE="Arial" LANG="0">Yeah, 100% of the Motorola-brand 4046s worked on 50mv! I tested 2 tubes of them (50 units) and all were okee-dokee on 50mv.<BR>
<BR>
I wasn't worried about the change in amplitude for the product design I did. I ended up approving all the popular manufacturer's parts and simply changed the production spec for a level adjustment elsewhere in the system. I had spec'd 200mv and there was plenty of reserve to simply have the level jacked up higher. Cake. Once in a while one gets to thumb their nose at Murphy ... but not very often! Now the time I misread a spec sheet and put in a part that was 1.5 orders of magnitude too slow ... uh, never mind. That didn't happen. It was only a dream. Really. Didn't happen! <grin><BR>
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Peace.<BR>
Tom Farrand<BR>
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In a message dated 1/6/2006 11:11:04 AM Central Standard Time, harrybissell@prodigy.net writes:<BR>
<BR>
<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">I think it would be wrong to call the input stage 'amplifier'... buffer<BR>
is probably better as it would not have any gain.<BR>
<BR>
The usual input voltage transition point should be 1/2Vdd... but the logic<BR>
'high' and 'low' levels from that point are not guaranteed.<BR>
<BR>
You're lucky if you were really using a 50mV signal... there is no guarantee<BR>
but if it works, it works.<BR>
<BR>
The point of manufacturer differences is VERY important. Sometimes they<BR>
make equivalent chips are ARE different. One counter chip had an input<BR>
with schmitt triggers on two inputs, which were then AND'ed. Another<BR>
manufacturer used the AND gate first, and schmitt triggered the output.<BR>
DUH... what good does the schmitt trigger do, if it is not the first<BR>
stage.<BR>
<BR>
Anyone using the 4046 would be wise to use a comparator or other signal<BR>
conditioner to guarantee logic levels first, before the signal input... and especially<BR>
if using phase comparator II (which you all will :^)<BR>
<BR>
H^) harry<BR>
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