ADS1292 datasheet(24/69 Pages) TI

24 / 69 page

100

120

140

Normalized Frequency (f /f

)

IN DR

0.5

4.5

3.5

2.5

1.5

0.5

1.5

2.5

Normalized Frequency (f /f

)

IN DR

0.05

0.1

0.15

0.35

0.2

0.25

0.3

100

120

140

Normalized Frequency (f /f

)

IN MOD

0.05

0.1

0.5

0.15

0.2

0.25

0.3

0.35

0.4

0.45

DR[2:0] = 000

DR[2:0] = 110

100

120

140

Normalized Frequency (f /f

)

IN MOD

0.01

0.07

0.02

0.03

0.04

0.05

0.06

DR[2:0] = 110

DR[2:0] = 000

110

130

Normalized Frequency (f /f

)

IN MOD

0.5

1.5

2.5

3.5

DR[2:0] = 000

DR[2:0] = 110

ADS1291

ADS1292

ADS1292R

SBAS502A – DECEMBER 2011 – REVISED MARCH 2012

www.ti.com

The sinc filter has notches (or zeroes) that occur at the output data rate and multiples thereof. At these

frequencies, the filter has infinite attenuation. Figure 26 shows the sinc filter frequency response and Figure 27

shows the sinc filter roll-off. With a step change at input, the filter takes 3 tDR to settle. After a START signal

rising edge, the filter takes tSETTLE time to give the first data output. The filter settling times at various data rates

are discussed in the START subsection of the SPI Interface section. Figure 28 and Figure 29 show the filter

transfer function until fMOD/2 and fMOD/16, respectively, at different data rates. Figure 30 shows the transfer

function extended until 4 fMOD. It can be seen that the ADS1291, ADS1292, and ADS1292R passband repeats

itself at every fMOD. The input R-C anti-aliasing filters in the system should be chosen such that any interference

in frequencies around multiples of fMOD are attenuated sufficiently.

Figure 26. Sinc Filter Frequency Response

Figure 27. Sinc Filter Roll-Off

Figure 28. Transfer Function of On-Chip

Figure 29. Transfer Function of On-Chip

Decimation Filters Until fMOD/2

Decimation Filters Until fMOD/16

Figure 30. Transfer Function of On-Chip Decimation Filters

Until 4fMOD for DR[2:0] = 000 and DR[2:0] = 110

Submit Documentation Feedback

Product Folder Link(s): ADS1291 ADS1292 ADS1292R

ADS1292 Datasheet(PDF) 24 Page - Texas Instruments

ADS1292 Datasheet(HTML) 24 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69

Datasheet Download

Link URL