
2
AD7714
REV. C
–13–
BUFFERED MODE NOISE
Table III shows the typical output rms noise and effective resolution for some typical notch and –3dB frequencies for the AD7714-
5 with f
CLKIN
= 2.4576MHz and BUFFER = +5 V. Table IV gives the information for the AD7714-3 again with f
CLK IN
= 2.4576
MHz and BUFFER = +5V. The numbers given are for the bipolar input ranges and are generated with a differential analog input
voltage of 0V. For the AD7714-5, the V
REF
voltage is +2.5V while for the AD7714 the V
REF
voltage is +1.25V. The numbers in
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
REF
/GAIN). It should be noted that it is not
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.
Table III. AD7714-5 Buffered Mode Output Noise/Resolution for f
CLK IN
= 2.4576MHz
Filter First
Notch & O/P
Data Rate
Typical Output RMS Noise in
m
V (Effective Resolution in Bits)
Gain of
Gain of
Gain of
2
4
8
–3dB
Frequency
Gain of
Gain of
16
Gain of
32
Gain of
64
Gain of
128
1
5Hz
10Hz
25Hz
30Hz
50Hz
60Hz
100Hz
250Hz
500Hz
1kHz
1.31Hz
2.62Hz
6.55Hz
7.86Hz
13.1Hz
15.72Hz
26.2Hz
65.5Hz
131Hz
262Hz
0.99
1.5
2.5
2.9
4.2
6.1
13.8
87
508
2860 (11)
(22.5)
(21.5)
(21)
(20.5)
(20)
(19.5)
(18.5)
(16)
(13.5)
0.68
0.95
1.7
1.8
2.5
2.9
6.5
56
241
1700 (10.5)
(22)
(21.5)
(20.5)
(20.5)
(20)
(19.5)
(18.5)
(15.5)
(13.5)
0.46 (21.5)
0.63 (21)
0.88 (20.5)
1
(20)
1.5
(19.5)
2
(19.5)
3.5
(18.5)
25
(15.5)
117 (13.5)
745 (10.5)
0.26 (21)
0.41 (20.5) 0.39 (19.5) 0.36 (18.5) 0.36 (17.5) 0.36 (16.5)
0.75 (19.5) 0.57 (19)
0.57 (18)
0.87 (19.5) 0.75 (18.5) 0.72 (17.5) 0.72 (16.5) 0.71 (15.5)
1.1
(19)
0.94 (18.5) 0.94 (17.5) 0.94 (16.5) 0.87 (15.5)
1.2
(19)
1
(18.5) 0.97 (17.5) 0.95 (16.5) 0.94 (15.5)
2.2
(18)
1.3
(18)
1.2
11
(15.5) 5.7
(15.5) 3.6
73
(13)
34
(13)
16
480 (10.5) 197 (10.5) 94
0.26 (20)
0.26 (19)
0.26 (18)
0.26 (17)
0.57 (17)
0.56 (16)
(17)
(15.5) 2.4
(13)
(10.5) 53
1.3
(16)
(15)
(13)
(10.5) 23
1.1
2.1
5.2
(15)
(14)
(13)
(10.5)
8.5
Table IV. AD7714-3 Buffered Mode Output Noise/Resolution for f
CLK IN
= 2.4576MHz
Filter First
Notch & O/P
Data Rate
Typical Output RMS Noise in
m
V (Effective Resolution in Bits)
Gain of
Gain of
Gain of
2
4
8
–3dB
Frequency
Gain of
Gain of
16
Gain of
32
Gain of
64
Gain of
128
1
5Hz
10Hz
25Hz
30Hz
50Hz
60Hz
100Hz
250Hz
500Hz
1kHz
1.31Hz
2.62Hz
6.55Hz
7.86Hz
13.1Hz
15.72Hz
26.2Hz
65.5Hz
131Hz
262Hz
1.16
1.7
3.5
3.7
4.5
5.3
10
47
300
1722 (10.5)
(21)
(20.5)
(19.5)
(19.5)
(19)
(19)
(18)
(15.5)
(13.5)
0.76
1
1.8
2.2
3
3.3
4.9
29
171
735
(20.5)
(20.5)
(19.5)
(19)
(18.5)
(18.5)
(18)
(15.5)
(13)
(10.5)
0.34 (20)
0.7
1.1
1.3
1.7
1.8
3.1
15
74
380 (10.5)
0.29 (20)
0.46 (19.5) 0.45 (18.5) 0.4
0.74 (18.5) 0.63 (18)
0.76 (18.5) 0.68 (18)
1.0
(18)
0.92 (17.5) 0.9
1.1
(18)
1
1.5
(17.5) 1.2
7.5
(15.5) 4.7
35
(13)
21
230 (10.5) 93
0.29 (19)
0.28 (18)
0.26 (17)
0.26 (16)
(20)
(19)
(19)
(18.5)
(18.5)
(17.5)
(15.5)
(13)
(17.5) 0.4
(17)
(16.5) 0.4
(16)
(15.5)
(15)
0.6
0.66 (17)
0.6
0.66 (16)
0.6
0.66 (15)
(16.5) 0.89 (15.5) 0.89 (14.5)
0.96 (16.5) 0.96 (15.5) 0.96 (14.5)
1.2
(16)
1.2
(15)
2.6
(15)
2.5
(14)
8.6
(13)
5.6
(13)
(10.5) 55
(10.5) 30
(17)
(17)
(15)
(13)
1.2
1.6
3.1
(14)
(13.5)
(12.5)
(10.5)
(10.5) 12