Help designing a low-noise TIA

[George Herold]

On Wednesday, June 12, 2019 at 11:06:35 AM UTC-4, Jan Panteltje wrote:

On a sunny day (Wed, 12 Jun 2019 05:49:54 -0700 (PDT)) it happened George
Herold <gherold@teachspin.com> wrote in
9fc32656-f716-43e5-86c8-99b12f4f8248@googlegroups.com>:

On a sunny day (Tue, 11 Jun 2019 10:11:45 GMT) it happened Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote in <qdnup7$odi$1@dont-email.me>:
So.. after a night sleep...
And thinking about the FM modulator and audio like bandwidth low noise thing
a quick search with google for
'microphone preamplifier integrated circuit 80dB'
found this as first hit:
http://www.thatcorp.com/press34.shtml

I downloaded the datasheet from
http://www.thatcorp.com/1510-1512_Audio_Preamplifier_ICs.shtml

Hmm, I wonder about the input bias current and offset. ~1 uA
=~ 200uV, x1000 is 200mV... or is that not a problem?

I think for a reasonable temperature range subtracting a few hundred mV and setting zero before the measurement
is not a problem.


JL's low noise int amp had a bunch of bias current too...
so maybe that isn't a problem.

One could look for better mike pre-amps chips.
Also can we use AC ? We will see a pulse AFAIK?

Right, I think it's a tiny pulse that lasts for a second,
myabe a bit less.

GH

I see that 1512 on ebay, 2 for 20 $, plus shipping from US source:
https://www.ebay.com/itm/262773847594