SCPS275A July 2021 – December 2021 TCA9536
PRODUCTION DATA
When an I/O is configured as an input, FETs Q1 and Q2 are off, creating a high-impedance input with a weak pull-up (100 kΩ typical with roughly 20% tolerance) to VCC. This internal weak pull-up can be disabled via the special function register if desired. The input voltage may be raised above VCC to a maximum of 5.5 V.
If the I/O is configured as an output, Q1 or Q2 is enabled, depending on the state of the output port register. In this case, there are low-impedance paths between the I/O pin and either VCC or GND. The external voltage applied to this I/O pin should not exceed the recommended levels for proper operation.