AD2S80A_closed loop bandwidth

Document created by analog-archivist Employee on Feb 23, 2016
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How could I choose the closed-loop bandwidth (fBW with the AD2S80A
Are there guidelines.
Resolution                 Ratio of Reference Frequency/Bandwidth
10                              2.5 : 1
12                              4 : 1
14                              6 : 1
16                             7.5 : 1
Could you please help to give some comments on it? Thanks.

 

That section is a little confusing I agree.

The data sheet states,
5. Closed-Loop Bandwidth Selection (C4, C5, R5)
a. Choose the closed-loop bandwidth (fBW) required
ensuring that the ratio of reference frequency to bandwidth
does not exceed the following guidelines:
Resolution Ratio of Reference Frequency/Bandwidth
10 2.5 : 1
12 4 : 1
14 6 : 1
16 7.5 : 1
Typical values may be 100 Hz for a 400 Hz reference frequency
and 500 Hz to 1000 Hz for a 5 kHz reference frequency.

This would be better interpreted as choose a bandwidth at least the ratios
mentioned.
For example with 12 bits resolution and a 5 kHz reference frequency the
bandwidth should be 1.25kHz maximum but down to 500Hz or a 10:1 ratio should be
fine.

If the customer continues to have trouble determining the component values I
can provide some assistance or I suggest the component selection program. It
can be found at
http://ez.analog.com/message/41875#41875
if you scroll down through the text.

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