SCPS267B March 2017 – February 2020 TCA9803
Selecting the pull-up resistor required for the A-side (Bus A) is well documented already, see the I2C Bus Pullup Resistor Calculation application report. The rest of this section deals only with selection of a device based on the B-side design requirements.
Selection process of each device is identical to the procedure described in the Device Selection Guide section, except that it must be done for each individual TCA980x. This section jumps straight to the selection graphs to show the selection process. See the Detailed Design Procedure section for single device for detailed information.
Based on Figure 32, the TCA9802 or the TCA9803 are the devices which are able to meet the design requirements. The TCA9802 is the most optimized selection, but the TCA9803 can be used without issue.
Based on Figure 33, all 4 variants of the TCA980x family meet the design requirements. The TCA9800 is the most optimized selection, but any of the variants can be used without issue.
As the system designer, the choice can be made to go for the most optimized part selections (TCA9802 for bus B and TCA9800 for bus C), but it is also ok to use the TCA9802 or the TCA9803 on both busses, because they both satisfy the design requirements of both busses.