2

AD7714

REV. C

–13–

BUFFERED MODE NOISE

Table III shows the typical output rms noise and effective resolution for some typical notch and –3 dB frequencies for the AD7714-

MHz and BUFFER = +5 V. The numbers given are for the bipolar input ranges and are generated with a differential analog input

brackets in each table are for the effective resolution of the part (rounded to the nearest 0.5 LSB). The effective resolution of the

device is defined as the ratio of the output rms noise to the input full scale (i.e., 2

× V

calculated using peak-to-peak output noise numbers. Peak-to-peak noise numbers can be up to 6.6 times the rms numbers while

effective resolution numbers based on peak-to-peak noise can be 2.5 bits below the effective resolution based on rms noise as quoted

in the tables.

Filter First

Typical Output RMS Noise in

V (Effective Resolution in Bits)

Notch & O/P

–3 dB

Gain of

Gain of

Gain of

Gain of

Gain of

Gain of

Gain of

Gain of

Data Rate

Frequency

1

2

4

8

16

32

64

128

5 Hz

1.31 Hz

0.99

(22.5)

0.68

(22)

0.46 (21.5) 0.26 (21)

0.26 (20)

0.26 (19)

0.26 (18)

0.26 (17)

10 Hz

2.62 Hz

1.5

(21.5)

0.95

(21.5)

0.63 (21)

0.41 (20.5) 0.39 (19.5) 0.36 (18.5) 0.36 (17.5) 0.36 (16.5)

25 Hz

6.55 Hz

2.5

(21)

1.7

(20.5)

0.88 (20.5) 0.75 (19.5) 0.57 (19)

0.57 (18)

0.57 (17)

0.56 (16)

30 Hz

7.86 Hz

2.9

(20.5)

1.8

(20.5)

1

(20)

0.87 (19.5) 0.75 (18.5) 0.72 (17.5) 0.72 (16.5) 0.71 (15.5)

50 Hz

13.1 Hz

4.2

(20)

2.5

(20)

1.5

(19.5) 1.1

(19)

0.94 (18.5) 0.94 (17.5) 0.94 (16.5) 0.87 (15.5)

60 Hz

15.72 Hz

6.1

(19.5)

2.9

(19.5)

2

(19.5) 1.2

(19)

1

(18.5) 0.97 (17.5) 0.95 (16.5) 0.94 (15.5)

100 Hz

26.2 Hz

13.8

(18.5)

6.5

(18.5)

3.5

(18.5) 2.2

(18)

1.3

(18)

1.2

(17)

1.3

(16)

1.1

(15)

250 Hz

65.5 Hz

87

(16)

56

(15.5)

25

(15.5) 11

(15.5) 5.7

(15.5) 3.6

(15.5) 2.4

(15)

2.1

(14)

500 Hz

131 Hz

508

(13.5)

241

(13.5)

117 (13.5) 73

(13)

34

(13)

16

(13)

8.5

(13)

5.2

(13)

1 kHz

262 Hz

2860 (11)

1700 (10.5)

745 (10.5) 480 (10.5) 197 (10.5) 94

(10.5) 53

(10.5) 23

(10.5)

Filter First

Typical Output RMS Noise in

V (Effective Resolution in Bits)

Notch & O/P

–3 dB

Gain of

Gain of

Gain of

Gain of

Gain of

Gain of

Gain of

Gain of

Data Rate

Frequency

1

2

4

8

16

32

64

128

5 Hz

1.31 Hz

1.16

(21)

0.76

(20.5)

0.34 (20)

0.29 (20)

0.29 (19)

0.28 (18)

0.26 (17)

0.26 (16)

10 Hz

2.62 Hz

1.7

(20.5)

1

(20.5)

0.7

(20)

0.46 (19.5) 0.45 (18.5) 0.4

(17.5) 0.4

(16.5) 0.4

(15.5)

25 Hz

6.55 Hz

3.5

(19.5)

1.8

(19.5)

1.1

(19)

0.74 (18.5) 0.63 (18)

0.6

(17)

0.6

(16)

0.6

(15)

30 Hz

7.86 Hz

3.7

(19.5)

2.2

(19)

1.3

(19)

0.76 (18.5) 0.68 (18)

0.66 (17)

0.66 (16)

0.66 (15)

50 Hz

13.1 Hz

4.5

(19)

3

(18.5)

1.7

(18.5) 1.0

(18)

0.92 (17.5) 0.9

(16.5) 0.89 (15.5) 0.89 (14.5)

60 Hz

15.72 Hz

5.3

(19)

3.3

(18.5)

1.8

(18.5) 1.1

(18)

1

(17)

0.96 (16.5) 0.96 (15.5) 0.96 (14.5)

100 Hz

26.2 Hz

10

(18)

4.9

(18)

3.1

(17.5) 1.5

(17.5) 1.2

(17)

1.2

(16)

1.2

(15)

1.2

(14)

250 Hz

65.5 Hz

47

(15.5)

29

(15.5)

15

(15.5) 7.5

(15.5) 4.7

(15)

2.6

(15)

2.5

(14)

1.6

(13.5)

500 Hz

131 Hz

300

(13.5)

171

(13)

74

(13)

35

(13)

21

(13)

8.6

(13)

5.6

(13)

3.1

(12.5)

1 kHz

262 Hz

1722 (10.5)

735

(10.5)

380 (10.5) 230 (10.5) 93

(10.5) 55

(10.5) 30

(10.5) 12

(10.5)