Hello Goya-san, If you're using the ADS1278 in an isolated system you may consider operating the product in TDM mode to reduce the number of digital lines required to cross the isolation barrier. This will limit the data throughput versus using the 8 DOUT lines in discrete data mode. Figure 77 below shows the interface in TDM mode and Figure 80 shows the discrete mode interface. In TDM mode you'll need three isolator channels (SCLK, DOUT, and DRDY/FSYNC). In SPI mode DRDY is an output and in frame-sync mode it is an input to the ADS1278 . In discrete mode you'll need 10 isolation channels (SCLK, DOUT1-8, DRDY/FSYNC) SCLK will be an input, DOUT1-8 are outputs, and in SPI mode DRDY is an output and in frame-sync mode FSYNC is an input. The ISO77xx family of digital isolators will work well for this application and there are 6/4/3/2/1 channel variants depending on the communication mode you choose.
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