JAJSLC0 March 2024 ADC3683-SP
PRODMIX
The PDN/SYNC pin can be used to synchronize multiple devices using an external SYNC signal. The PDN/SYNC pin can be configured via SPI (SYNC EN bit) from power down to synchronization functionality, and is latched in by the rising edge of the sampling clock as shown in Figure 7-33.
The synchronization signal is only required when using the decimation filter. Either using the SPI SYNC register or the PDN/SYNC pin. The internal clock divider is reset and used in the decimation filter. Aligning the internal clocks as well as I and Q data within the same sample. If no SYNC signal is given, the internal clock dividers are not synchronized. Leading to a fractional delay across different devices. The SYNC signal also resets the NCO phase, and loads the new NCO frequency (same as the MIXER RESTART bit).
When trying to resynchronize during operation, the SYNC toggle occurs at 64*K clock cycles, where K is an integer. This provides a phase continuity of the clock divider.