CS5012A, CS5014, CS5016
100 dB
80 dB
60 dB
40 dB
20 dB
0 dB
0dB
-20dB
-40dB
-60dB
-80dB
-100dB
-120dB
Sampling Rate: 56 kHz
Full Scale: 9V p-p
S/(N+D): 24.1 dB
1 kHz
12 kHz
24 kHz
Input
Frequencies
Signal
Amplitude
Relative to
Full Scale
-100 dB -80 dB -60 dB -40 dB -20 dB
0 dB
1 kHz
28 kHz
dc
Analog Input Amplitude
Input Frequency
Figure 27. CS5014 FFT plot with 1 kHz
-60 dB Input
Figure 26. CS5014 S/(N+D) vs. Input Amplitude
(9Vp-p Full-Scale Input)
100 dB
0dB
1 kHz
12 kHz
Sampling Rate: 50 kHz
Full Scale: 9V p-p
S/(N+D): 9.6 dB
-20dB
-40dB
80 dB
24 kHz
Input
60 dB
40 dB
20 dB
0 dB
Frequency
-60dB
Signal
Amplitude
Relative to
Full Scale
-80dB
-100dB
-120dB
1 kHz
25 kHz
-100 dB -80 dB -60 dB -40 dB -20 dB
0 dB
dc
Input Frequency
Analog Input Amplitude
Figure 28. CS5016 S/(N+D) vs. Input Amplitude
(9Vp-p Full-Scale Input)
Figure 29. CS5016 FFT plot with 1 kHz
-80 dB Input
rms with a 4.5V reference in both modes. Figure
30 shows a histogram plot of output code occur-
rences obtained from 5000 samples taken from a
CS5016 in the bipolar mode. Hexadecimal code
80CD was arbitrarily selected and the analog in-
put was set close to code center. With a noiseless
converter, code 80CD would always appear. The
histogram plot of the CS5016 has a "bell" shape
with all codes other than 80CD due to internal
noise.
Signal to Noise + Distortion vs Signal Level
As illustrated in Figures 26 - 29, the CS5014/16’s
on-chip self-calibration provides very accurate bit
weights which yield no degradation in quantiza-
tion noise with low-level input signals. In fact,
quantization noise remains below the noise floor
in the CS5016, which dictates the converter’s sig-
nal-to-noise performance.
CS5016 Noise Considerations
In a sampled data system all information about the
analog input applied to the sample/hold appears in
the baseband from dc to one-half the sampling rate.
This includes high-frequency components which
alias into the baseband. Low-pass (anti-alias) filters
All analog circuitry in the CS5016 is wideband in
order to achieve fast conversions and high
throughput. Wideband noise in the CS5016 inte-
grates to 35 µV rms in unipolar mode (70 µV rms
in bipolar mode). This is approximately 1/2 LSB
2-34
DS14F6
CIRRUS [ CIRRUS LOGIC ]
