MAX1402 Datasheet, PDF (28/40 Pages) Maxim Integrated Products – +5V, 18-Bit, Low-Power, Multichannel, Oversampling Sigma-Delta ADC

+5V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
Table 16b. MAX1402 Noise vs. Gain and Output Data Rate—Buffered Mode,
V_REF = 2.5V, f_CLKIN = 2.4576MHz
OUTPUT
DATA
RATE
(sps)
-3dB
FREQ.
(Hz)
x1
TYPICAL OUTPUT NOISE IN µV_RMS
PROGRAMMABLE GAIN
BIT
STATUS
x2
x4
x8
x16
x32
x64
x128
MF1:MF0 = 0
50
13.1
6.05
4.13
2.35
1.50
1.40
1.32
1.37
1.39
FS1:FS0 = 0
60
15.7
7.11
4.24
2.54
1.64
1.49
1.53
1.49
1.48
FS1:FS0 = 1
300
78.6
142.02 71.62
35.65
18.32
9.35
5.60
4.10
3.52
FS1:FS0 = 2
600
157.2 823.33 405.95 195.95 102.14 50.28
25.85
13.75
7.78
FS1:FS0 = 3
MF1:MF0 = 1
100
26.2
8.10
3.66
2.25
1.52
1.34
1.31
1.34
1.35
FS1:FS0 = 0
120
31.4
8.37
4.12
2.53
1.64
1.45
1.49
1.45
1.46
FS1:FS0 = 1
600
157.2 143.45 69.52
36.04
17.77
9.32
5.48
3.92
3.41
FS1:FS0 = 2
1200
314.4 830.30 408.48 201.87 101.39 52.39
26.77
13.50
7.87
FS1:FS0 = 3
MF1:MF0 = 2
200
52.4
6.55
3.21
1.92
1.35
1.24
1.16
1.16
1.10
FS1:FS0 = 0
240
62.9
7.40
3.89
2.24
1.47
1.35
1.29
1.22
1.25
FS1:FS0 = 1
1200
314.4 148.57 73.71
36.80
18.08
9.92
5.26
3.64
3.02
FS1:FS0 = 2
2400
628.8 851.32 408.09 202.57 105.18 52.98
25.71
13.33
7.97
FS1:FS0 = 3
MF1:MF0 = 3
400
104.8
6.60
3.83
2.21
1.38
1.28
1.21
1.17
1.21
FS1:FS0 = 0
480
125.7
7.58
4.14
2.28
1.58
1.40
1.34
1.30
1.31
FS1:FS0 = 1
2400
628.8 144.96 68.92
35.92
17.36
9.52
5.45
3.79
3.21
FS1:FS0 = 2
4800
1258 803.87 394.00 205.60 102.18 52.48
26.07
13.59
7.89
FS1:FS0 = 3
20
19
18
17
16
15
14
13
12
11
10
1
a) BUFF = 0
CLK = 1
FS1: FS0 = 0 OR 1
FS1: FS0 = 2
FS1: FS0 = 3
CLK = 1
BUFF = 0
2 4 8 16 32 64 128
GAIN (V/V)
Figure 8. Effective Resolution vs. Gain and Notch Frequency
Effective Resolution = (SNR_dB - 1.76dB) / 6.02
The maximum possible signal divided by the noise of
the device, SNR_dB, is defined as the ratio of the input
full-scale voltage (i.e., 2 · V_REFIN / GAIN) to the output
rms noise. Note that it is not calculated using peak-to-
20
19
18
17
16
15
14
13
12
11
10
1
b) BUFF = 1
FS1: FS0 = 0 OR 1
FS1: FS0 = 2
FS1: FS0 = 3
CLK = 1
BUFF = 1
2 4 8 16 32 64 128
GAIN (V/V)
peak output noise numbers. Peak-to-peak noise num-
bers 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.
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