ADS9813 datasheet(28/66 Pages) TI1

28 / 66 page

6.3.6.2 ADC Output Data Randomizer

The ADS9813 features a data output randomizer. When enabled, the ADC conversion result is bit-wise

exclusive-ORed (XOR) with either the LSB of the conversion result (Figure 6-9) or XOR_PRBS bit that can

be appended to the ADC data output (Figure 6-8). The LSB of the ADC conversion result and XOR_PRBS have

equal probability of being either 1 or 0. As a result of the XOR operation, the data output from the ADS9813 is

randomized. The ground bounce created by the transmission of this randomized result over the data interface is

uncorrelated with the analog input voltage. This uncorrelated transmission helps minimize interference between

data transmission and analog performance of the ADC when the PCB layout does not minimize ground bounce.

MSB

MSB - 1

MSB - 2

LSB + 1

LSB

MSB

MSB - 1

MSB - 2

LSB + 1

LSB

ADC Conversion

Result

Bit-wise

XOR

Randomized

Result

PRBS bit

PRBS bit is appended after LSB of conversion result

Figure 6-8. Bit-Wise XOR Operation with PRBS Bit

MSB

MSB - 1

MSB - 2

LSB + 1

LSB

MSB

MSB - 1

MSB - 2

LSB + 1

LSB

ADC Conversion

Result

Bit-wise

XOR

Randomized

Result

LSB of conversion result is used for XOR operation

Figure 6-9. Bit-Wise XOR Operation with ADC LSB

6.3.6.3 Data Averaging

The ADS9813 features two modes of data averaging to improve SNR - simple average and moving average.

Simple averaging reduces the output data rate by a factor of 2 whereas moving average does not affect the

output data rate. Table 6-10 and Table 6-11 show the register operations to enable and disable the simple

average and moving average respectively.

Table 6-10. Register Operations for Simple Average

STEP #

ENABLE SIMPLE AVERAGE

DISABLE SIMPLE AVERAGE

REG_BANK_SEL

EN_AVG

AVG_CFG3

AVG_CFG2

AVG_CFG1

AVG_CFG4

Table 6-11. Register Operations for Moving Average

STEP #

ENABLE SIMPLE AVERAGE

DISABLE SIMPLE AVERAGE

REG_BANK_SEL

EN_AVG

EN_MVG_AVG

ADS9813, ADS9811, ADS9810

SBASAQ6A – JULY 2024 – REVISED NOVEMBER 2024

www.ti.com

Submit Document Feedback

Product Folder Links: ADS9813 ADS9811 ADS9810

ADS9813 Datasheet(PDF) 28 Page - Texas Instruments

ADS9813 Datasheet(HTML) 28 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

Datasheet Download

Link URL