Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
References: <3D760B64.CC303206@scs.uiuc.edu> <3D763949.4B6D795E@scs.uiuc.edu> <firstname.lastname@example.org> <email@example.com>
Subject: Re: High impedance low noise
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Date: Thu, 12 Sep 2002 07:42:22 +0100
NNTP-Posting-Date: Thu, 12 Sep 2002 07:42:24 BST
"James Meyer" wrote in message
> On Wed, 11 Sep 2002 15:07:19 +0200, "fred bartoli"
> >> > Also don't forget the TI winners
> >> > f_T e_n Cin max Vcc
> >> > (MHz) (nV) (pF) (+/-V)
> >> > ----- ----- ---- ------
> >> > THS4021 350 1.5 1.5 +/-16 stable G>10
> >> > THS4031 100 1.6 1.5 +/-16 stable G>2
> >> > THS4011 290 7.5 1.2 +/-16
> >> Indeed those are nice amplifers, but they aren't JFET input
> >> oamps, and they have an input current of up to 6uA, which
> >> would be a killer for Jim, I suspect!!
> >I just found those amps for my VNA IF amplifier and their nice perfs
> >forget this point.
> How about using the best op-amp you can find regardless of its input
> circuit and adding a junction FET like the matched, dual, U430 from
> a front end? You won't find a lower noise device than the U430. It's
I have not checked it data sheet for this one, but does it beat the
2sk162 (dual) which generates only 0.65 nv/rthz, with a very low 1/f
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.