CS5012A, CS5014, CS5016
0dB
-20dB
-40dB
-60dB
-80dB
-100dB
-120dB
0dB
-20dB
-40dB
-60dB
-80dB
-100dB
-120dB
Sampling Rate: 50 kHz
Full Scale: 9V p-p
S/(N+D): 92.4 dB
S/(N+D): 97.5 dB
Signal
Signal
Amplitude
Relative to
Full Scale
Amplitude
Relative to
Full Scale
1 kHz
25 kHz
dc
f /2
s
dc
Input Frequency
Input Frequency
Figure 24. CS5016 FFT plot with 1 kHz
Full Scale Input
Figure 23. Plot of Ideal 16-bit ADC
CS5012A High Frequency Performance
analysis with the Discrete Fourier Transform",
Proc. IEEE, Vol. 66, No. 1, Jan 1978, pp.51-83.
This is available on request from Crystal Semi-
conductor.
The CS5012A performs very well over a wide
range of input frequencies as shown in Figure 25.
The figure depicts the CS5012A-KP7 tested un-
der four different conditions. The conditions
include tests with the voltage reference set at 4.5
and at 2.5 volts with input signals at 0.5 dB down
from full scale and 6.0 dB down from full scale.
The sample rate is at 100 kHz for all cases. The
plots indicate that the part performs very well
even with input frequencies above the Nyquist
rate. Best performance at the higher frequencies
is achieved with a 2.5 volt reference.
Figures 19, 22, and 24 show the performance of
the CS5012A/14/16 with 1kHz full scale inputs.
Figure 20 shows CS5012A performance with
12kHz full scale inputs. Notice that the perform-
ance CS5012A/14/16 closely approaches that of
the corresponding ideal ADC.
75
f =100 kHz
s
CS5012A-KP7
VREF
Signal
1.
2.
3.
4.
4.5
2.5
4.5
2.5
FS-0.5dB
FS-0.5dB
FS-6.0dB
FS-6.0dB
1
70
65
60
55
Signal to
Noise +
Distortion
2
(dB)
4
3
0
20
40
60
80
100
s
120
140
160
180
200
f
/2
f
s
Input Frequency (kHz)
Figure 25. CS5012A High Frequency Input Performance
DS14F6
2-33
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