[sdiy] Odp: low input bias current opamps

[Tim Ressel]

agreed


On 8/15/2018 10:11 AM, Justin Herrmann wrote:
> That might be your most limiting factor here, that the component must 
> be through hole. There's so much more selection available in SMD, it's 
> not even funny.
>
> Justin
> On 08/15/2018, 11:48 AM Pete Hartman <pete.hartman at gmail.com> wrote:
>
>     Is an SMD -> TH adapter an option, Dave?
>
>     That would save you having to do any SMD layout, but let you get
>     the advantage of the better/newer SMD parts....
>
>     On Wed, Aug 15, 2018 at 11:10 AM, Roman <modular at go2.pl
>     <mailto:modular at go2.pl>> wrote:
>
>         The answer to A) is no, because of 1)
>         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.
>
>         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.
>         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.
>
>         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.
>
>         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.
>
>         Roman
>
>         Dnia 15 sierpnia 2018 05:48 David G Dixon <dixon at mail.ubc.ca
>         <mailto:dixon at mail.ubc.ca>> napisał(a):
>
>             Hey Team,
>
>             I'm looking for opamps with the following properties:
>
>             1) Through-hole
>             2) Quad opamp
>             3) 14-DIP package
>             4) High power range (+/-18V, say)
>             5) Low input bias current (10 pA or less typical)
>             6) Pin-compatible with TL074, etc.
>             7) Not LF444 (cuz they all seem to be defective)
>
>             So, basically, I'm looking for a suitable alternative for
>             LF444.
>
>             So, here are my questions:
>
>             A) Do you know of such a thing
>             B) How does one go about finding such a thing, generally?
>
>             Thanks in advance!
>             Dave (Floating VCA) Dixon
>
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-- 
--Tim Ressel
Circuit Abbey
timr at circuitabbey.com

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