Lpc2000

This seems to be a power supply decoupling problem because the ADC seems to
draw more current during the conversion process. Did you follow the basic
rules for high resolution ADCs regarding board layout (ground planes,
massive power traces, sufficient high frequency decoupling capacitors 100n
in closest proximity to the ADC, electrolytics somewhat further from the
device)? You could also try LC filtering the supply lines for the ADC and
reference IC.

Regards,

Jan

----- Original Message ----- 
From: "Leighton Rowe" <leightonsrowe@...>
To: <lpc2000@yahoogroups.com>
Sent: Wednesday, February 09, 2005 3:41 PM
Subject: [lpc2000] External ADC Problem


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> I need a little advice with using external ADC's with lpc
> processors.
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> Apparently, the reference, analog ground, and input signals looks
> somewhat distorted (spiky) on the oscilloscope whenever the 16-bit
> (unipolar) Converter is busy converting. As a result, the readings
> don't come out as consistent as it should (even when both inputs are
> grounded). Is there any way to avoid this problem?
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> Yahoo! Groups Links
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