PCA9306-Q1 has the capability of being used with its V_REF1 voltage equal to V_REF2. This essentially turns the device from a translator to a device which can be used as a switch, and in some situations this can be useful. The switch configuration is shown in Figure 9-5 and translation mode is shown in Figure 9-6.

Figure 9-5 Switch Configuration

Figure 9-6 Translation Configuration

When PCA9306-Q1 is in the switch configuration (V_REF1 = V_REF2), the propagation delays are different compared to the translator configuration. Taking a look at the propagation delays, if the pull up resistance and capacitance on both sides of the bus are equal, then in switch mode the PCA9306-Q1 has the same propagation delay from side one to two and side two to one. The propagation delays become lower when V_CC1/V_CC2 is larger. For example, the propagation delay at 1.8 V is longer than at 5 V in the switching configuration. When PCA9306-Q1 is in translation mode, side one propagate lows to side two faster than side two can propagate lows to side 1. This time difference increases as the difference between V_CC2 and V_CC1 becomes larger.