ADS54J20 Datasheet, PDF (27/81 Pages) Texas Instruments – Dual-Channel, 12-Bit, 1.0-GSPS, Analog-to-Digital Converter

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ADS54J20
SBAS766A – MAY 2016 – REVISED MAY 2016
Feature Description (continued)
8.3.2.1 Decimate-by-2 Filter
This decimation filter has 41 taps. The stop-band attenuation is approximately 90 dB and the pass-band flatness
is ±0.05 dB. Table 1 shows corner frequencies for the low-pass and high-pass filter options.
Table 1. Corner Frequencies for the Decimate-by-2 Filter
CORNERS (dB)
–0.1
–0.5
–1
–3
LOW PASS
0.202 × f_S
0.210 × f_S
0.215 × f_S
0.227 × f_S
HIGH PASS
0.298 × f_S
0.290 × f_S
0.285 × f_S
0.273 × f_S
Figure 60 and Figure 61 show the frequency response of the decimate-by-2 filter from dc to f_S / 2.
5
-20
-45
-70
-95
-120
0
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Frequency Response
D013
0.5
0
-0.5
-1
-1.5
-2
-2.5
-3
0
0.05
0.1
0.15
0.2
Frequency Response
0.25
D014
Figure 60. Decimate-by-2 Filter Response
Figure 61. Decimate-by-2 Filter Response (Zoomed)
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