Datasheet

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SBAS312B − JANUARY 2005 − REVISED AUGUST 2007
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11
TYPICAL CHARACTERISTICS (continued)
AV
DD
= 5V, BV
DD
= 3V, CH x+ = 0.5V to 4.5V, CH x− = 2.5V, REFIN = REFOUT = internal +2.5V, CLKIN = 20MHz, and 16-bit Sinc
3
filter with
decimation by 256, unless otherwise noted.
Figure 20
FREQUENCY SPECTRUM
(4096 point FFT f
IN
=1kHz,4V
PP
)
0
−
20
−
40
−
60
−
80
−
100
−
120
−
140
−
160
Magnitude (dB)
Frequency (kHz)
0246
8 10 12 14 16 18 19
Figure 21
FREQUENCY SPECTRUM
(4096 point FFT f
IN
=5kHz,4V
PP
)
0
−
20
−
40
−
60
−
80
−
100
−
120
−
140
−
160
Magnitude (dB)
Frequency (kHz)
0246
8 10 12 14 16 18 19
Figure 22
EFFECTIVE NUMBER OF BITS
vs DECIMATION RATIO
10 100 1k
Decimation Ratio (OSR)
ENOB (Bits)
16
14
12
10
8
6
4
2
SNR (dB)
98
86
74
62
50
38
26
14
Sinc
2
Filter
Sinc
3
Filter
Figure 23
POWER−SUPPLY CURRENT
vs TEMPERATURE
−
40
−
20 0 20 40 60 80 100
Temperature (
_
C)
Current (mA)
16
15
14
13
12
11
10
9
8
CLKSEL = 1
CLKSEL = 0, CLKIN = 20MHz
CLKSEL = 0, CLKIN = 32MHz
Figure 24
COMMON−MODE REJECTION RATIO
vs FREQUENCY
100 1k 10k 100k 1M
Input Frequency (kHz)
CMRR (dB)
130
120
110
100
90
Figure 25
POWER−SUPPLY REJECTION RATIO
vs FREQUENCY
100 1k 10k
Frequency of Power Supply (kHz)
PSRR (dB)
100
90
80
70
60