JAJSIB2 December 2019 ADC3421-Q1
PRODUCTION DATA.
The devices are equipped with an internal chopper front-end. Enabling the chopper function swaps the ADC noise spectrum by shifting the 1/f noise from dc to fS / 2. Figure 43 shows the noise spectrum with the chopper off and Figure 44 shows the noise spectrum with the chopper on. This function is especially useful in applications requiring good ac performance at low input frequencies or in dc-coupled applications. The chopper can be enabled via SPI register writes and is recommended for input frequencies below 30 MHz. The chopper function creates a spur at fS / 2 that must be filtered out digitally.
SNR = 71.1 dBFS, SINAD = 71.1 dBFS
SFDR = 97 dBc ,THD = 95 dBc |
SNR = 71 dBFS, SINAD = 71 dBFS
SFDR = 96 dBc, THD = 97 dBc |