Figure 9-2 depicts how the ADS131B04-Q1 can be configured for the minimum number of interface pins. This configuration is useful when using data isolation to minimize the number of isolation channels required or when the microcontroller (MCU) pins are limited.

The CLKIN pin requires an LVCMOS clock that can be either generated by the MCU or created using a local LVCMOS output oscillator when the device is configured for use with an external clock. Otherwise tie the CLKIN pin to DGND if the internal oscillator is used. Tie the SYNC/RESET pin to DVDD in hardware if unused. The DRDY pin can be left floating if unused. Connect either SYNC/RESET or DRDY to the MCU to make sure the MCU stays synchronized to ADC conversions. If the MCU provides CLKIN, the CLKIN periods can be counted to determine the sample period rather than forcing synchronization using the SYNC/RESET pin or monitoring the DRDY pin. Synchronization cannot be regained if a bit error occurs on the clock and samples can be missed if the SYNC/RESET or DRDY pins are not used. CS can be tied low in hardware if the ADS131B04-Q1 is the only device on the SPI bus. Make sure the data input and output CRC are enabled and are used to guard against faulty register reads and writes if CS is tied low permanently.

Figure 9-2 Minimum Connections Required to Operate the ADS131B04-Q1