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Re: [Amps] help diagnosing a bad 8450a probe ?

To: Dan Sawyer <dansawyer@earthlink.net>, g3rzp@g3rzp.wanadoo.co.uk
Subject: Re: [Amps] help diagnosing a bad 8450a probe ?
From: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Reply-to: g3rzp@g3rzp.wanadoo.co.uk
Date: Fri, 9 Dec 2005 20:40:17 +0100 (CET)
List-post: <mailto:amps@contesting.com>
>From memory, the original diodes are matched to a 5mV forward drop at 1mA. You 
>can get some funny results if they aren't matched, as you get some of the 
>switching signal coming through - from memory. teh effects will be at maximum 
>sensitivity.
As Steve says, getting diodes from the same batch will probably do it. It's 
just that matched diodes come from about the same place on the wafer: it is not 
uncommon to get a variation across a wafer, although it's probably more 
apparent with the 12 inch wafers used these days for CMOS. This semiconductor 
processing stuff is far more of a black art than the manufacturers would have 
you believe - you have to have the right person spit in the mixture!
Not that  27 years working in the semiconductor business has made me cynical - 
and no comments from GM3SEK on that!

73
Peter G3RZP
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