COMBOSMARTMETER datasheet(21/60 Pages) TI1

21 / 60 page

100

120

140

NormalizedFrequency(f /f

)

IN MOD

0.01

0.07

0.02

0.03

0.04

0.05

0.06

DR[2:0]=000

DR[2:0]=110

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] = 110

DR[2:0] = 000

-20

-40

-60

-80

-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

ADS131E04

ADS131E06

ADS131E08

www.ti.com

SBAS561A – JUNE 2012 – REVISED APRIL 2013

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 23 shows the sinc filter frequency response and Figure 24

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

the START signal, the filter takes tSETTLE time to output settled data. The filter settling times at various data rates

are discussed in the START subsection of the SPI Interface section. Figure 25 and Figure 26 show the filter

transfer function until fMOD / 2 and fMOD / 16, respectively, at different data rates. Figure 27 shows the transfer

function extended until 4 fMOD. It can be seen that the ADS131E0x passband repeats itself at every fMOD. The

input R-C antialiasing filters in the system should be chosen such that any interference in frequencies around

multiples of fMOD are attenuated sufficiently.

Figure 23. Sinc Filter Frequency Response

Figure 24. Sinc Filter Roll-Off

Figure 25. Transfer Function of On-Chip

Figure 26. Transfer Function of On-Chip

Decimation Filters Until fMOD / 2

Decimation Filters Until fMOD / 16

Submit Documentation Feedback

Product Folder Links: ADS131E04 ADS131E06 ADS131E08

COMBOSMARTMETER Datasheet(PDF) 21 Page - Texas Instruments

COMBOSMARTMETER Datasheet(HTML) 21 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

Datasheet Download

Link URL