Anybody got a working AD592 interface circuit?
Hi all:
Does anyone have a worked-out practical circuit they can share
which will interface an AD592 temp. probe to a BS2[noparse][[/noparse]|e|sx|p]?
FYI The AD592 is a two terminal device to which you apply 4-30VDC,
and regardless of voltage, it will always pass 1uA per degree Kelvin,
or in other words between 248uA (@ -25C) to 378uA (@ +105C), linearly.
So how to convert a narrow range of very small current flow into
something either rctime or an A/D can deal with.
I'm looking for at least 8 bits of resolution over this range.
Thanks for any cookbook examples anyone can share...
Ken N2TIA
Does anyone have a worked-out practical circuit they can share
which will interface an AD592 temp. probe to a BS2[noparse][[/noparse]|e|sx|p]?
FYI The AD592 is a two terminal device to which you apply 4-30VDC,
and regardless of voltage, it will always pass 1uA per degree Kelvin,
or in other words between 248uA (@ -25C) to 378uA (@ +105C), linearly.
So how to convert a narrow range of very small current flow into
something either rctime or an A/D can deal with.
I'm looking for at least 8 bits of resolution over this range.
Thanks for any cookbook examples anyone can share...
Ken N2TIA
Comments
>From: Ken Stamm <n2tia@a...>
>Reply-To: basicstamps@egroups.com
>To: basicstamps@egroups.com
>Subject: [noparse][[/noparse]basicstamps] Anybody got a working AD592 interface circuit?
>Date: Tue, 23 Jan 2001 14:26:02 -0500
>
>Hi all:
>
>Does anyone have a worked-out practical circuit they can share
>which will interface an AD592 temp. probe to a BS2[noparse][[/noparse]|e|sx|p]?
>
>FYI The AD592 is a two terminal device to which you apply 4-30VDC,
>and regardless of voltage, it will always pass 1uA per degree Kelvin,
>or in other words between 248uA (@ -25C) to 378uA (@ +105C), linearly.
>
>So how to convert a narrow range of very small current flow into
>something either rctime or an A/D can deal with.
>I'm looking for at least 8 bits of resolution over this range.
>
>Thanks for any cookbook examples anyone can share...
>
>Ken N2TIA
>
>
>
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>
>Does anyone have a worked-out practical circuit they can share
>which will interface an AD592 temp. probe to a BS2[noparse][[/noparse]|e|sx|p]?
>
>FYI The AD592 is a two terminal device to which you apply 4-30VDC,
>and regardless of voltage, it will always pass 1uA per degree Kelvin,
>or in other words between 248uA (@ -25C) to 378uA (@ +105C), linearly.
>
>So how to convert a narrow range of very small current flow into
>something either rctime or an A/D can deal with.
>I'm looking for at least 8 bits of resolution over this range.
>
>Thanks for any cookbook examples anyone can share...
>
>Ken N2TIA
Hi Ken,
I have a write-up on my web site at
http://www.emesys.com/OWL2face.htm#AD590
Also the AD590 is the subject of unit 3 in the stampsinclass Earth
Measurements text:
http://www.emesys.com/EarthM/em3.pdf
http://www.emesys.com/EarthM/emapps.pdf <--contruction of waterproof probe
The AD590 and AD592 have been on distributer allocation recently.
The newer TMP17 is an identical part electrically, but mounted in an
8 pin SOIC instead of a TO92 or TO52. I have heard the '17 is made
on a different fab line.
-- Tracy Allen
electronically monitored ecosystems
http://www.emesystems.com