In page number 5 of the MAX19777 datasheet, Figure 1 shows the timing diagram where the DOUT data timing parameters t7 and t4 together with the SCLK period, define the interval where stable DOUT should be read. The definition may seem a bit confusing at first due to overlap, but at 48MHz, DOUT will be stable during a window between 2.166ns and 5ns after the SCLK falling edge.
The MAX19777 supports 3MSps throughput at SCLK = 48MHz, where DOUT should be sampled during the interval between 2.166ns and 5ns after the SCLK falling edge.