Datasheet

Data Sheet AD7176-2
Rev. A | Page 31 of 68
ENHANCED 50 HZ AND 60 HZ REJECTION FILTERS
The enhanced filters are designed to provide rejection of 50 Hz
and 60 Hz simultaneously and to allow the user to trade off
settling time and rejection. These filters can operate up to
27.27 SPS or can reject up to 90 dB of 50 Hz ± 1 Hz and 60 Hz
± 1 Hz interference. These filters are realized by post filtering
the output of the Sinc5 + Sinc1 filter. For this reason, the Sinc5
+ Sinc1 filter must be selected when using the enhanced filters.
Table 20 shows the output data rates with the accompanying
settling time, rejection, and rms noise. Figure 39 to Figure 46
show the frequency domain plots of the responses from the
enhanced filters.
Table 20. AD7176-2 Enhanced Filters Output Data Rate, Noise, Settling Time (t
SETTLE
), and Rejection Using the Enhanced Filters
Output Data Rate
(SPS)
Settling Time
(ms)
Simultaneous Rejection of
50 Hz ± 1 Hz and 60 Hz ± 1 Hz
(dB)
1
Noise
(μV rms)
Peak-to-Peak
Resolution (Bits)
Comments
27.27 36.67 47
0.45 21.7
See
Figure 39 and Figure 40
25 40.0 62
0.45 21.7
See
Figure 41 and Figure 42
20 50.0 85
0.44 22
See
Figure 43 and Figure 44
16.667 60.0 90
0.44 22
See
Figure 45 and Figure 46
1
Master clock = 16 MHz.