EVAL-AD7762EB View Datasheet(PDF) - Analog Devices

Part Name

Description

MFG CO.

EVAL-AD7762EB

625 kSPS, 24-Bit, 109 dB Σ−Δ ADC With On-Chip Buffer

Analog Devices 

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AD7762

Table 13 shows the hex values (in sign and magnitude format)

that are downloaded to the AD7762 to realize this filter. The

table is also split into the bytes that are all summed to produce

the checksum. The checksum generated from these coefficients

is 0x0E6B.

Table 13. Filter Hex Values

Word 1

Coefficient Byte 1 Byte 2

1

03

2B

2

01

BF

3

00

15

4

04

A8

5

04

5F

6

00

2C

7

00

50

8

00

10

9

04

2F

10

04

37

11

04

1B

12

04

04

Word 2

Byte 3 Byte 4

96

88

18

3C

66

26

1E

6A

2A

96

49

C2

E9

F6

DB

D8

DE

54

44

5A

7D

6E

3B

5F

Table 14 lists the 16-bit words the user would write to the

AD7762 to set up the ADC and download this filter, assuming

an output data rate of 625 kHz has already been selected.

Table 14.

Word

0x0001

0x8079

0x032B

0x9688

0x01BF

0x183C

…

0x0404

0x3B5F

0x0E6B

0x0001

0x0879

Description

Address of Control Register 1.

Control register data. DL filter, set filter length = 24,

set output data rate = 625 kHz.

First coefficient, Word 1.

First coefficient, Word 2.

Second coefficient, Word 1.

Second coefficient, Word 2.

Other coefficients.

Twelfth (final) coefficient, Word 1.

Final coefficient, Word 2.

Checksum. Wait (0.5 × tICLK × Number of Unused

Coefficients) for AD7762 to fill remaining unused

coefficients with 0s.

Address of control register.

Control register data. Set read status and maintain

filter length and decimation settings. Read contents

of status register. Check Bit 7 (DL_OK) to determine

that the filter was downloaded correctly.

Rev. 0 | Page 22 of 28

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