cs5317 Cirrus Logic, Inc., cs5317 Datasheet - Page 16

• Manufacturer Part Number: cs5317
• Description: 16-bit, 20 Khz Oversampling A/d Converter
• Manufacturer: Cirrus Logic, Inc.

Full - scale signal - to - noise - plus - distortion
[S/(N+D)] is calculated as the ratio of the rms
power of the fundamental to the sum of the rms
power of the FFT’s other frequency bins, which
include both noise and distortion. For the
CS5317, signal-to-noise-plus-distortion is shown
to be better than 81 dB for an input frequency
range of 0 to 9.6 kHz (fs/2).
Harmonic distortion characteristics of the CS5317
are excellent at 80 dB full scale signal to THD
(typical), as are intermodulation distortion char-
acteristics, shown in Figure 8. Intermodulation
distortion results from the modulation distortion
of two or more input frequencies by a non-linear
transfer function.
DNL Test
Figure 9 shows a plot of the typical differential
non-linearity (DNL) of the CS5317. This test is
done by taking a large number of conversion re-
sults, and counting the occurrences of each code.
A perfect A/D converter would have all codes of
equal size and therefore equal numbers of occur-
rences. In the DNL test, a code with the average
number of occurrences is considered ideal and
plotted as DNL = 0 LSB. A code with more or
less occurrences than average will appear as a
DNL of greater than or less than zero. A missing
code has zero occurrences, and will appear as a
DNL of -1 LSB.
16
+1/2
-1/2
+1
-1
0
0
Figure 9. CS5317 DNL Plot
Codes
32,768
Signal
Amplitude
Relative to
Full Scale
The plot below illustrates the typical DNL per-
formance of the CS5317, and clearly shows the
part easily achieves no missing codes.
Figure 8. CS5317 Intermodulation Distortion
-100dB
-120dB
-20dB
-40dB
-60dB
-80dB
Schematic & Layout Review Service
C a l l : ( 5 1 2 ) 4 4 5 - 7 2 2 2
0dB
Confirm Optimum
Confirm Optimum
Schematic & Layout
Schematic & Layout
Before Building Your Board.
Before Building Your Board.
For Our Free Review Service
For Our Free Review Service
Call Applications Engineering.
Call Applications Engineering.
dc
800
1450
Input Frequency (Hz)
S/I.M.D.: 84.7 dB
CS5317
65,535
DS27F4
9600