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<DIV dir=ltr align=left><SPAN class=248123117-15082018><FONT color=#0000ff
size=2 face=Arial>Thanks for the great response, Roman.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=248123117-15082018><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=248123117-15082018><FONT color=#0000ff
size=2 face=Arial>Possibly stupid follow-up question: </FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=248123117-15082018><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=248123117-15082018><FONT color=#0000ff
size=2 face=Arial>Why would ESD have an effect on a JFET-input opamp? I
thought that only CMOS was susceptible to ESD, because of the oxide gate
insulator, but not JFET. The LF444 should be no more susceptible to
handling issues than TL074. The handling would have to have been
unbelievably abusive to damage the chips, I would have
thought.</FONT></SPAN></DIV>
<DIV><SPAN class=248123117-15082018><FONT color=#0000ff size=2
face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=248123117-15082018><FONT color=#0000ff size=2 face=Arial>If I'm
wrong about this, please disabuse me!</FONT></SPAN></DIV>
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<FONT size=2 face=Tahoma><B>From:</B> Roman [mailto:modular@go2.pl]
<BR><B>Sent:</B> Wednesday, August 15, 2018 9:10 AM<BR><B>To:</B> David G
Dixon; synth-diy@synth-diy.org<BR><B>Subject:</B> Odp: [sdiy] low input bias
current opamps<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV>The answer to A) is no, because of 1)<BR></DIV>
<DIV>Recently I made some THT design and was just so happy about it until I
found how many parts that I freely use in SMD are simply not made in THT, so
the choice usually comes to one part if any.<BR></DIV>
<DIV><BR></DIV>
<DIV>The answer to B) is usually Mouser, but they have sometimes errors in
describing parameters, or take different values to the table, like "typical"
for one part and "minimum" for the other part. Sometimes I use DigiKey, mostly
because they seem to have more refined parameters to search and I can type the
quantity of interest, and then sort by the price. Mouser sorts only at qty 1
which is useless.<BR></DIV>
<DIV>And obviously all manufacturer's websites contain parametric search,
which is the most accuratre, but still I prefer Mouser because it gives me
guidance of the price and availability.<BR></DIV>
<DIV><BR></DIV>
<DIV>And if it's for some S&H, why don't you stick with TL0xx? Are you
sure your switching key has lower leakage than bias of TL0xx opamp? Or try
LF347 maybe but it's inferior to LF444 in this application anyway.<BR></DIV>
<DIV><BR></DIV>
<DIV>Give LF444 a chance, get new ones, maybe they were handled very badly and
inputs were damaged by ESD because of bad storage. They would still work but
bias may be in range of nA instead of pA.<BR></DIV>
<DIV><BR></DIV>
<DIV>Roman<BR></DIV>
<DIV class=nh_extra>
<P>Dnia 15 sierpnia 2018 05:48 David G Dixon <dixon@mail.ubc.ca>
napisał(a):<BR></P>
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<DIV id=gwp3c8fd2db>
<DIV>Hey Team,<BR></DIV>
<DIV><BR></DIV>
<DIV>I'm looking for opamps with the following properties:<BR></DIV>
<DIV><BR></DIV>
<DIV>1) Through-hole<BR></DIV>
<DIV>2) Quad opamp<BR></DIV>
<DIV>3) 14-DIP package<BR></DIV>
<DIV>4) High power range (+/-18V, say)<BR></DIV>
<DIV>5) Low input bias current (10 pA or less typical)<BR></DIV>
<DIV>6) Pin-compatible with TL074, etc.<BR></DIV>
<DIV>7) Not LF444 (cuz they all seem to be defective)<BR></DIV>
<DIV><BR></DIV>
<DIV>So, basically, I'm looking for a suitable alternative for
LF444.<BR></DIV>
<DIV><BR></DIV>
<DIV>So, here are my questions:<BR></DIV>
<DIV><BR></DIV>
<DIV>A) Do you know of such a thing<BR></DIV>
<DIV>B) How does one go about finding such a thing, generally?<BR></DIV>
<DIV><BR></DIV>
<DIV>Thanks in advance!<BR></DIV>
<DIV>Dave (Floating VCA) Dixon<BR></DIV>
<DIV><BR></DIV>
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