Texas Instruments ADS9224REVM-PDK, User Manual, Page: 17 / 34

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17 SBAU315A – July 2018 – Revised June 2019
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ADS9224REVM-PDK
6.4 Spectral Analysis Tool
The spectral analysis tool evaluates the dynamic performance (SNR, THD, SFDR, SINAD, and ENOB) of
the ADS9224R SAR ADC. Evaluation is done through single-tone sinusoidal signal FFT analysis using the
7-term Blackman-Harris window setting. The window setting of
None can be used to search for noise
spurs over frequency in dc inputs.
For dynamic performance evaluation, the external differential source must have better specifications than
the ADC. The measured system performance must not be limited by the performance of the signal source.
Therefore, the external reference source must meet the source requirements mentioned in
Table 6 .
Table 6. External Source Requirements for Evaluation of the ADS9224R
Specification Description Specification Value
Signal frequency Less than f
S
/ 2
External source type Balanced differential
External source common-mode voltage 0 V or floating
Source differential signal
(V
PP
amplitude for –0.5 dBFS)
±3.875 V
P
OR 7.75 V
PP
Maximum noise 20 µV
RMS
Minimum SNR 103.2 dB
Maximum THD –120 dB
For 2-kHz SNR and ENOB evaluation at a maximum throughput of 3 MSPS, the number of samples must
be a minimum of 65536.
Figure 13. Spectral Analysis Tool