The Spectral Analysis tool (Figure 6-4) is intended to evaluate the dynamic performance (SNR, THD, SFDR, SINAD, and ENOB) of the ADS7953 SAR ADC through the use of a single-tone, sinusoidal signal fast Fourier transform (FFT) analysis, using the 7-term Blackman-Harris window setting. Alternatively, the window setting of None can be used to search for noise spurs over frequency in DC inputs.

For dynamic performance evaluation, the external, single-ended source must have better specifications than the ADC to make sure that the measured system performance is not limited by the performance of the signal source. Therefore, the external reference source must meet the source requirements listed in Table 6-1. Alternately, the user can use the Precision Signal Injector EVM that provides a low-distortion, low-noise, 2-kHz input signal for driving the input of the ADC, and pairs with most of the TI SAR ADC evaluation modules (EVMs). The board is powered over a USB, which also provides a user-interface connection to a PC.

Figure 6-4 Spectral Analysis Tool