10.2.2.2 V_ILC and Pullup Resistor Sizing

For the TCA9517 to function correctly, all devices on the B-side must be able to pull the B-side below the voltage input low contention level (V_ILC). This means that the V_OL of any device on the B-side must be below
0.4 V.

V_OL of a device can be adjusted by changing the I_OL through the device which is set by the pull-up resistance value. The pull-up resistance on the B-side must be carefully selected to ensure that logic levels will be transferred correctly to the A-side.

Figure 8. Typical Star Application

Multiple A sides of TCA9517 s can be connected in a star configuration, allowing all nodes to communicate with each other.

Figure 9. Typical Series Application

To further extend the I²C bus for long traces/cables, multiple TCA9517 s can be connected in series as long as the A-side is connected to the B-side. I²C bus slave devices can be connected to any of the bus segments. The number of devices that can be connected in series is limited by repeater delay/time-of-flight considerations on the maximum bus speed requirements.

Figure 10. Bus A (0.9 V to 5.5 V Bus) Waveform

Figure 11. Bus B (2.7 V to 5.5 V Bus) Waveform