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From: Tilmann Reh
Subject: Re: Current Source Multiplexer
Date: Thu, 21 Nov 2002 16:04:26 +0100
Organization: Autometer GmbH
NNTP-Posting-Date: 21 Nov 2002 15:04:10 GMT
X-Mailer: Mozilla 4.78 [de] (Windows NT 5.0; U)
> I have a project about to start that requires the use of a current
> multiplexer. Specifically there are N current sources ranging between 1 nA
> and 10 mA, only one of which should appear at the output.
> Has anyone ever had to deal with a circuit like this? I am hoping for a
> circuit that will not degrade bandwidth or introduce error, even at 1 nA
> (impossible I know, but I can always hope:)
> Typical multiplexers I have seen are intended to operate on voltage sources
> and would have too high of a crosstalk (~25 dB) to be of much use for this
You could try using discrete JFETs but as others already pointed to,
the range of seven decades will probably arise some problems.
However, I think with discrete JFETs you'll get at least the most of
what you can get at all.
Dipl.-Ing. Tilmann Reh
Autometer GmbH Siegen - Elektronik nach Maß.
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