Thd+N Vs Frequency (600Ω Load) Using X7R Input Caps; Fft Spectrum With -60Dbfs Tone - Texas Instruments DRV600EVM User Manual

DRV600EVM Performance
The DRV600EVM uses a 1μF film capacitor for ac-coupling of the input signal. If a lower cost ceramic
capacitor such as an X7R is used, higher THD at low frequencies should be expected. Y5V capacitors will
show even higher THD performance and should not be used.
Figure 8. THD+N vs Frequency (600Ω load) Using X7R Input Caps
The X7R capacitors raises the 20Hz THD from 0.02% to 0.1%—five times higher.
4.3.1 FFT Spectrum with –60dBFS Tone
Reference voltage is 2V
This spectrum corresponds to a dynamic range of 110dB, A-weighted. SNR measures at 110dB,
A-weighted.
8 DRV600EVM User's Guide
10
1
0.1
0.01
0.001
20 100
Frequency (Hz)
, FFT size 16k.
RMS
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
0 2k 4k 6k 8k
Frequency (Hz)
Figure 9. FFT Spectrum with –60dBFS Tone
Right
Left
1k 10k 20k
10k 12k 14k 16k 18k 20k 22k
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SLOU205 – July 2007
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