The MAX11190 uses a modified 3-wire digital interface, but is compatible with the standard SPI protocol. The three connections are DOUTx (MISO equivalent) and SCLK, and CS. Master-to-slave communication, which is limited to entering shutdown mode, is controlled by the rising edge of CS. Standard SPI protocol pulls CS high after the last SCLK pulse, which will allow you to read data, but could limit the sampling rate to lower than the maximum 3Msps. To achieve the full sampling rate, CS should be pulled high after the 10th clock pulse and before the 16th. To enter shutdown mode, CS must be pulled high after the 2nd clock pulse and before the 10th. This slight modification to SPI protocol is easy to implement by controlling the CS line directly in your host processor program.
