[sdiy] Question about LM301A

[Paul Maddox (QinetiQ)]

Hi,

surely it would be better to use something along the lines of a TL081/071 ?
or even one of the DG series from Maxim?

something like a noise gen you would want as high an input impedance as
possible so as not to load the source.

Paul
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----- Original Message -----
From: "patchell" <patchell at silcom.com>
To: "Ken MacBeth" <macbeth2600 at yahoo.co.uk>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, July 16, 2002 3:08 PM
Subject: Re: [sdiy] Question about LM301A


>     The LM301A is more or less just an improved 741.  It has better DC
> specs than the 741, as I recall (i.e. much better Vos drift, lower bias
> current).  It also has external compensation.  If you are running the
> 301 invertered, you can use feed forward compensation and get something
> like 10V/us Slew rate out of it (compared to the 0.5V/us using the
> standard compensation, which makes it have pretty much the same AC
> characteristics as the 741).  However, I have found that you need to be
> careful using the feed forward as in some applications it causes more
> problems than it cures.
>
>     The LM108 is the military temp range version of the LM308, so, they
> are identical.  The LM308 has much better DC characteristics than the
> LM301 (very low bias current, very low Vos drift).  However, it has very
> poor AC performance.  It is only suitable for DC and Very low frequency
> AC (5KHz is about tops).
>
> Ken MacBeth wrote:
>
> >     Hi! I am just wondering what is so special about the LM301A? I see
> > it used in many designs- I use it in an Arp noise gen. copy. I've
> > replaced it with the basic 741 and the results have been unusable...
> > Also, I have a stack 'gold and white' LM108's- can I use them in
> > circuits that use the 308?
> > Any answers appreciated! Regards, Ken
>
> --
>  -Jim
> ------------------------------------------------
> * Visit:http://www.silcom.com/~patchell/
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> *I'm sure glad Merry Christmas comes just once a year
> * -Yogi Yorgensen
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