Rainbow Electronics MAX1402 - Manual (Page 28)

MAX1402
+5V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
28 ______________________________________________________________________________________
Table 16b. MAX1402 Noise vs. Gain and Output Data Rate—Buffered Mode,
V
REF = 2.5V, f CLKIN = 2.4576MHz
PROGRAMMABLE GAIN
x1 x2 x4 x8 x16 x32 x64 x128 MF1:MF0 = 0
FS1:FS0 = 3 7.89 13.59 26.07 52.48 102.18 205.60 394.00 803.87 1258 4800
FS1:FS0 = 3 7.97 13.33 25.71 52.98 105.18 202.57 408.09 851.32 628.8 2400
FS1:FS0 = 2 3.02 3.64 5.26 9.92 18.08 36.80 73.71 148.57 314.4 1200
FS1:FS0 = 1 1.25 1.22 1.29 1.35 1.47 2.24 3.89 7.40 62.9 240
FS1:FS0 = 0 1.10 1.16 1.16 1.24 1.35 1.92 3.21 6.55 52.4 200
MF1:MF0 = 2
FS1:FS0 = 3 7.87 13.50 26.77 52.39 101.39 201.87 408.48 830.30 314.4 1200
FS1:FS0 = 2 3.41 3.92 5.48 9.32 17.77 36.04 69.52 143.45 157.2 600
FS1:FS0 = 1 1.46 1.45 1.49 1.45 1.64 2.53 4.12 8.37 31.4 120
FS1:FS0 = 2 3.21 3.79 5.45 9.52 17.36 35.92 68.92 144.96 628.8 2400
FS1:FS0 = 1 1.31 1.30 1.34 1.40 1.58 2.28 4.14 7.58 125.7 480
FS1:FS0 = 0 1.21 1.17 1.21 1.28 1.38 2.21 3.83 6.60 104.8 400
MF1:MF0 = 3
FS1:FS0 = 0 1.35 1.34 1.31 1.34 1.52 2.25 3.66 8.10 26.2 100
MF1:MF0 = 1
FS1:FS0 = 3 7.78 13.75 25.85 50.28 102.14 195.95 405.95 823.33 157.2 600
FS1:FS0 = 2 3.52 4.10 5.60 9.35 18.32 35.65 71.62 142.02 78.6 300
FS1:FS0 = 1 1.48 1.49 1.53 1.49 1.64 2.54 4.24 7.11 15.7 60
FS1:FS0 = 0
BIT
STATUS
1.39
TYPICAL OUTPUT NOISE IN µV RMS
1.37 1.32 1.40 1.50 2.35
OUTPUT
DATA
RATE
(sps)
4.13 6.05 13.1 50
-3dB
FREQ.
(Hz)
10
12
11
14
13
16
15
17
19
18
20
1 4 8 2 16 32 64 128
GAIN (V/V) b) BUFF = 1 a) BUFF = 0
EFFECTIVE RESOLUTION (BITS)
10
12
11
14
13
16
15
17
19
18
20
1 4 8 2 16 32 64 128
GAIN (V/V)
EFFECTIVE RESOLUTION (BITS)
FS1: FS0 = 0 OR 1
FS1: FS0 = 2
FS1: FS0 = 3
CLK = 1
FS1: FS0 = 0 OR 1
FS1: FS0 = 2
FS1: FS0 = 3
CLK = 1
BUFF = 1 CLK = 1
BUFF = 0
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-
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.