10.1.1 Basic Interface Connections

Figure 18 shows the principle I²C connections for the TLA202x.

Figure 18. Typical Interface Connections of the TLA202x

The TLA202x interface directly to standard-mode or fast-mode I²C controllers. Any microcontroller I²C peripheral, including master-only and single-master I²C peripherals, operates with the TLA202x. The TLA202x do not perform clock-stretching (that is, the devices never pull the clock line low), so this function does not need to be provided for unless other clock-stretching devices are present on the same I²C bus.

Pullup resistors are required on both the SDA and SCL lines because I²C bus drivers are open-drain. The size of these resistors depends on the bus operating speed and capacitance of the bus lines. Higher-value resistors yield lower power consumption when the bus lines are pulled low, but increase the transition times on the bus, which limits the bus speed. Lower-value resistors allow higher interface speeds, but at the expense of higher power consumption when the bus lines are pulled low. Long bus lines have higher capacitance and require smaller pullup resistors to compensate. Do not use resistors that are too small because the bus drivers may be unable to pull the bus lines low.

See the I²C-Bus Specification and User Manual from NXP Semiconductors for more details on pullup resistor sizing.