DS90LV048A: DS90LV047A DS90LV011A DS90LV012A

This depends on the propagation delays and the clock frequency. You need a feedback clock when the four propagation delays (logic-to-LVDS and LVDS-to-logic for MOSI plus logic-to-LVDS and LVDS-to-logic for MISO) are so large that the signal edges at the master's MISO pin arrive later than the current clock pulse.