Dear all,
I have a question about the ADC.
If I use a ADC chip and a MUX etc., and the ADC has the internal MUX and internal sample and hold, do I still need a sample and hold after the MUX before the ADC?
Many thanks,
Regards
ADC, Do I need a sample and hold chip?
Sep 22, 2007
2 Replies
No; it already has a s/h, right? But anyhow, if the chip has an integrated mux and s/h, how could you get between them to add another s/h?
The two common integrated adc architectures, these days, are delta-sigma and charge-balance successive approximation, and neither neeeds an external s/h.
A little anti-aliasing filtering is always prodent.
John
True, but for a 30 Hz low pass filter, the scan rate would have to be Bloody Slow - a half second per channel might work. And the OP now says he wants to scan all 24 channels in 50 mS.
Peter Bennett, VE7CEI
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