EVAL-AD7715-3EBZ View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'EVAL-AD7715-3EBZ' PDF : 40 Pages View PDF
AD7715
OUTPUT NOISE
AD7715-5
Table 15 shows the AD7715-5 output rms noise for the selecta-
ble notch and −3 dB frequencies for the part, as selected by FS1
and FS0 of the setup register. The numbers given are for the
bipolar input ranges with a VREF of 2.5 V. These numbers are
typical and are generated at a differential analog input voltage
of 0 V with the part used in unbuffered mode (BUF bit of the
setup register = 0). Table 16 meanwhile shows the output peak-
to-peak noise for the selectable notch and −3 dB frequencies
for the part. It is important to note that these numbers represent
the resolution for which there is no code flicker. They are not
calculated based on rms noise but on peak-to-peak noise. The
numbers given are for the bipolar input ranges with a VREF of
2.5 V and for the BUF bit of the setup register = 0. These num-
bers are typical, are generated at an analog input voltage of 0 V
and are rounded to the nearest LSB.
Meanwhile, Table 17 and Table 18 show rms noise and peak-
to-peak resolution respectively with the AD7715-5 operating
under the same conditions as above except that now the part is
operating in buffered mode (BUF bit of the setup register = 1).
Table 15. Output RMS Noise vs. Gain and Output Update Rate for AD7715-5 (Unbuffered Mode)
Filter First Notch and Output Data Rate −3 dB Frequency
Typical Output RMS Noise (μV)
MCLK IN =
2.4576 MHz
50 Hz
60 Hz
250 Hz
500 Hz
MCLK IN =
1 MHz
20 Hz
25 Hz
100 Hz
200 Hz
MCLK IN =
2.4576 MHz
13.1 Hz
15.72 Hz
65.5 Hz
131 Hz
MCLK IN =
1 MHz
5.24 Hz
6.55 Hz
26.2 Hz
52.4 Hz
Gain = 1
3.8
4.8
103
530
Gain = 2
1.9
2.4
45
250
Gain = 32
0.6
0.6
3.0
18
Gain = 128
0.52
0.62
1.6
5.5
Table 16. Peak-to-Peak Resolution vs. Gain and Output Update Rate for AD7715-5 (Unbuffered Mode)
Filter First Notch and Output Data Rate −3 dB Frequency
Typical Peak-to-Peak Resolution in Bits
MCLK IN =
MCLK IN =
MCLK IN =
MCLK IN =
2.4576 MHz
1 MHz
2.4576 MHz 1 MHz
Gain = 1 Gain = 2 Gain = 32
50 Hz
20 Hz
13.1 Hz
5.24 Hz
16
16
16
60 Hz
25 Hz
15.72 Hz
6.55 Hz
16
16
16
250 Hz
100 Hz
65.5 Hz
26.2 Hz
13
13
13
500 Hz
200 Hz
131 Hz
52.4 Hz
10
10
10
Gain = 128
14
13
12
10
Table 17. Output RMS Noise vs. Gain and Output Update Rate for AD7715-5 (Buffered Mode)
Filter First Notch and Output Data Rate −3 dB Frequency
Typical Output RMS Noise (μV)
MCLK IN = MCLK IN =
MCLK IN =
MCLK IN =
2.4576 MHz 1 MHz
2.4576 MHz 1 MHz
Gain = 1
Gain = 2
Gain = 32
50 Hz
20 Hz
13.1 Hz
5.24 Hz
4.3
2.2
0.9
60 Hz
25 Hz
15.72 Hz
6.55 Hz
5.1
3.1
1.0
250 Hz
100 Hz
65.5 Hz
26.2 Hz
103
50
3.9
500 Hz
200 Hz
131 Hz
52.4 Hz
550
280
18
Gain = 128
0.9
1.0
2.1
6
Table 18. Peak-to-Peak Resolution vs. Gain and Output Update Rate for AD7715-5 (Buffered Mode)
Filter First Notch and Output Data Rate −3 dB Frequency
Typical Peak-to-Peak Resolution in Bits
MCLK IN =
MCLK IN =
MCLK IN =
MCLK IN =
2.4576 MHz
1 MHz
2.4576 MHz 1 MHz
Gain = 1 Gain = 2 Gain = 32
50 Hz
20 Hz
13.1 Hz
5.24 Hz
16
16
15
60 Hz
25 Hz
15.72 Hz
6.55 Hz
16
16
15
250 Hz
100 Hz
65.5 Hz
26.2 Hz
13
13
13
500 Hz
200 Hz
131 Hz
52.4 Hz
10
10
10
Gain = 128
13
13
12
10
Rev. D | Page 16 of 40
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